/* Alias analysis for trees.
- Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009
+ Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
-#include "rtl.h"
#include "tm_p.h"
-#include "hard-reg-set.h"
+#include "target.h"
#include "basic-block.h"
#include "timevar.h"
-#include "expr.h"
#include "ggc.h"
#include "langhooks.h"
#include "flags.h"
#include "function.h"
-#include "diagnostic.h"
+#include "tree-pretty-print.h"
#include "tree-dump.h"
#include "gimple.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "convert.h"
#include "params.h"
-#include "ipa-type-escape.h"
#include "vec.h"
#include "bitmap.h"
#include "vecprim.h"
{
struct ptr_info_def *pi;
- /* ??? During SCCVN/PRE we can end up with *&x during valueizing
- operands. Likewise we can end up with dereferencing constant
- pointers. Just bail out in these cases for now. */
- if (TREE_CODE (ptr) == ADDR_EXPR
- || TREE_CODE (ptr) == INTEGER_CST)
+ /* Conversions are irrelevant for points-to information and
+ data-dependence analysis can feed us those. */
+ STRIP_NOPS (ptr);
+
+ /* Anything we do not explicilty handle aliases. */
+ if ((TREE_CODE (ptr) != SSA_NAME
+ && TREE_CODE (ptr) != ADDR_EXPR
+ && TREE_CODE (ptr) != POINTER_PLUS_EXPR)
+ || !POINTER_TYPE_P (TREE_TYPE (ptr))
+ || (TREE_CODE (decl) != VAR_DECL
+ && TREE_CODE (decl) != PARM_DECL
+ && TREE_CODE (decl) != RESULT_DECL))
return true;
- gcc_assert (TREE_CODE (ptr) == SSA_NAME
- && (TREE_CODE (decl) == VAR_DECL
- || TREE_CODE (decl) == PARM_DECL
- || TREE_CODE (decl) == RESULT_DECL));
+ /* Disregard pointer offsetting. */
+ if (TREE_CODE (ptr) == POINTER_PLUS_EXPR)
+ {
+ do
+ {
+ ptr = TREE_OPERAND (ptr, 0);
+ }
+ while (TREE_CODE (ptr) == POINTER_PLUS_EXPR);
+ return ptr_deref_may_alias_decl_p (ptr, decl);
+ }
+
+ /* ADDR_EXPR pointers either just offset another pointer or directly
+ specify the pointed-to set. */
+ if (TREE_CODE (ptr) == ADDR_EXPR)
+ {
+ tree base = get_base_address (TREE_OPERAND (ptr, 0));
+ if (base
+ && (TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF))
+ ptr = TREE_OPERAND (base, 0);
+ else if (base
+ && DECL_P (base))
+ return base == decl;
+ else if (base
+ && CONSTANT_CLASS_P (base))
+ return false;
+ else
+ return true;
+ }
/* Non-aliased variables can not be pointed to. */
if (!may_be_aliased (decl))
The caller is responsible for applying TBAA to see if accesses
through PTR1 and PTR2 may conflict at all. */
-static bool
+bool
ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
{
struct ptr_info_def *pi1, *pi2;
- /* ??? During SCCVN/PRE we can end up with *&x during valueizing
- operands. Likewise we can end up with dereferencing constant
- pointers. Just bail out in these cases for now. */
- if (TREE_CODE (ptr1) == ADDR_EXPR
- || TREE_CODE (ptr1) == INTEGER_CST
- || TREE_CODE (ptr2) == ADDR_EXPR
- || TREE_CODE (ptr2) == INTEGER_CST)
- return true;
+ /* Conversions are irrelevant for points-to information and
+ data-dependence analysis can feed us those. */
+ STRIP_NOPS (ptr1);
+ STRIP_NOPS (ptr2);
+
+ /* Disregard pointer offsetting. */
+ if (TREE_CODE (ptr1) == POINTER_PLUS_EXPR)
+ {
+ do
+ {
+ ptr1 = TREE_OPERAND (ptr1, 0);
+ }
+ while (TREE_CODE (ptr1) == POINTER_PLUS_EXPR);
+ return ptr_derefs_may_alias_p (ptr1, ptr2);
+ }
+ if (TREE_CODE (ptr2) == POINTER_PLUS_EXPR)
+ {
+ do
+ {
+ ptr2 = TREE_OPERAND (ptr2, 0);
+ }
+ while (TREE_CODE (ptr2) == POINTER_PLUS_EXPR);
+ return ptr_derefs_may_alias_p (ptr1, ptr2);
+ }
+
+ /* ADDR_EXPR pointers either just offset another pointer or directly
+ specify the pointed-to set. */
+ if (TREE_CODE (ptr1) == ADDR_EXPR)
+ {
+ tree base = get_base_address (TREE_OPERAND (ptr1, 0));
+ if (base
+ && (TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF))
+ return ptr_derefs_may_alias_p (TREE_OPERAND (base, 0), ptr2);
+ else if (base
+ && DECL_P (base))
+ return ptr_deref_may_alias_decl_p (ptr2, base);
+ else
+ return true;
+ }
+ if (TREE_CODE (ptr2) == ADDR_EXPR)
+ {
+ tree base = get_base_address (TREE_OPERAND (ptr2, 0));
+ if (base
+ && (TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF))
+ return ptr_derefs_may_alias_p (ptr1, TREE_OPERAND (base, 0));
+ else if (base
+ && DECL_P (base))
+ return ptr_deref_may_alias_decl_p (ptr1, base);
+ else
+ return true;
+ }
- gcc_assert (TREE_CODE (ptr1) == SSA_NAME
- && TREE_CODE (ptr2) == SSA_NAME);
+ /* From here we require SSA name pointers. Anything else aliases. */
+ if (TREE_CODE (ptr1) != SSA_NAME
+ || TREE_CODE (ptr2) != SSA_NAME
+ || !POINTER_TYPE_P (TREE_TYPE (ptr1))
+ || !POINTER_TYPE_P (TREE_TYPE (ptr2)))
+ return true;
/* We may end up with two empty points-to solutions for two same pointers.
In this case we still want to say both pointers alias, so shortcut
return pt_solutions_intersect (&pi1->pt, &pi2->pt);
}
-/* Return true if STMT is an "escape" site from the current function. Escape
- sites those statements which might expose the address of a variable
- outside the current function. STMT is an escape site iff:
-
- 1- STMT is a function call, or
- 2- STMT is an __asm__ expression, or
- 3- STMT is an assignment to a non-local variable, or
- 4- STMT is a return statement.
-
- Return the type of escape site found, if we found one, or NO_ESCAPE
- if none. */
+/* Return true if dereferencing PTR may alias *REF.
+ The caller is responsible for applying TBAA to see if PTR
+ may access *REF at all. */
-enum escape_type
-is_escape_site (gimple stmt)
+static bool
+ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref)
{
- if (is_gimple_call (stmt))
- {
- if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
- return ESCAPE_TO_PURE_CONST;
-
- return ESCAPE_TO_CALL;
- }
- else if (gimple_code (stmt) == GIMPLE_ASM)
- return ESCAPE_TO_ASM;
- else if (is_gimple_assign (stmt))
- {
- tree lhs = gimple_assign_lhs (stmt);
-
- /* Get to the base of _REF nodes. */
- if (TREE_CODE (lhs) != SSA_NAME)
- lhs = get_base_address (lhs);
-
- /* If we couldn't recognize the LHS of the assignment, assume that it
- is a non-local store. */
- if (lhs == NULL_TREE)
- return ESCAPE_UNKNOWN;
+ tree base = ao_ref_base (ref);
- if (gimple_assign_cast_p (stmt))
- {
- tree from = TREE_TYPE (gimple_assign_rhs1 (stmt));
- tree to = TREE_TYPE (lhs);
+ if (TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF)
+ return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0));
+ else if (DECL_P (base))
+ return ptr_deref_may_alias_decl_p (ptr, base);
- /* If the RHS is a conversion between a pointer and an integer, the
- pointer escapes since we can't track the integer. */
- if (POINTER_TYPE_P (from) && !POINTER_TYPE_P (to))
- return ESCAPE_BAD_CAST;
- }
-
- /* If the LHS is an SSA name, it can't possibly represent a non-local
- memory store. */
- if (TREE_CODE (lhs) == SSA_NAME)
- return NO_ESCAPE;
-
- /* If the LHS is a non-global decl, it isn't a non-local memory store.
- If the LHS escapes, the RHS escape is dealt with in the PTA solver. */
- if (DECL_P (lhs)
- && !is_global_var (lhs))
- return NO_ESCAPE;
-
- /* FIXME: LHS is not an SSA_NAME. Even if it's an assignment to a
- local variables we cannot be sure if it will escape, because we
- don't have information about objects not in SSA form. Need to
- implement something along the lines of
-
- J.-D. Choi, M. Gupta, M. J. Serrano, V. C. Sreedhar, and S. P.
- Midkiff, ``Escape analysis for java,'' in Proceedings of the
- Conference on Object-Oriented Programming Systems, Languages, and
- Applications (OOPSLA), pp. 1-19, 1999. */
- return ESCAPE_STORED_IN_GLOBAL;
- }
- else if (gimple_code (stmt) == GIMPLE_RETURN)
- return ESCAPE_TO_RETURN;
-
- return NO_ESCAPE;
+ return true;
}
fprintf (file, "\n\nAlias information for %s\n\n", funcname);
fprintf (file, "Aliased symbols\n\n");
-
- FOR_EACH_REFERENCED_VAR (var, rvi)
+
+ FOR_EACH_REFERENCED_VAR (cfun, var, rvi)
{
if (may_be_aliased (var))
dump_variable (file, var);
fprintf (file, "\nESCAPED");
dump_points_to_solution (file, &cfun->gimple_df->escaped);
- fprintf (file, "\nCALLUSED");
- dump_points_to_solution (file, &cfun->gimple_df->callused);
fprintf (file, "\n\nFlow-insensitive points-to information\n\n");
{
tree ptr = ssa_name (i);
struct ptr_info_def *pi;
-
+
if (ptr == NULL_TREE
|| SSA_NAME_IN_FREE_LIST (ptr))
continue;
/* Dump alias information on stderr. */
-void
+DEBUG_FUNCTION void
debug_alias_info (void)
{
dump_alias_info (stderr);
}
-/* Return the alias information associated with pointer T. It creates a
- new instance if none existed. */
-
-struct ptr_info_def *
-get_ptr_info (tree t)
-{
- struct ptr_info_def *pi;
-
- gcc_assert (POINTER_TYPE_P (TREE_TYPE (t)));
-
- pi = SSA_NAME_PTR_INFO (t);
- if (pi == NULL)
- {
- pi = GGC_CNEW (struct ptr_info_def);
- pt_solution_reset (&pi->pt);
- SSA_NAME_PTR_INFO (t) = pi;
- }
-
- return pi;
-}
-
/* Dump the points-to set *PT into FILE. */
void
if (pt->escaped)
fprintf (file, ", points-to escaped");
+ if (pt->ipa_escaped)
+ fprintf (file, ", points-to unit escaped");
+
if (pt->null)
fprintf (file, ", points-to NULL");
/* Dump points-to information for VAR into stderr. */
-void
+DEBUG_FUNCTION void
debug_points_to_info_for (tree var)
{
dump_points_to_info_for (stderr, var);
}
+
+/* Initializes the alias-oracle reference representation *R from REF. */
+
+void
+ao_ref_init (ao_ref *r, tree ref)
+{
+ r->ref = ref;
+ r->base = NULL_TREE;
+ r->offset = 0;
+ r->size = -1;
+ r->max_size = -1;
+ r->ref_alias_set = -1;
+ r->base_alias_set = -1;
+ r->volatile_p = ref ? TREE_THIS_VOLATILE (ref) : false;
+}
+
+/* Returns the base object of the memory reference *REF. */
+
+tree
+ao_ref_base (ao_ref *ref)
+{
+ if (ref->base)
+ return ref->base;
+ ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size,
+ &ref->max_size);
+ return ref->base;
+}
+
+/* Returns the base object alias set of the memory reference *REF. */
+
+static alias_set_type
+ao_ref_base_alias_set (ao_ref *ref)
+{
+ tree base_ref;
+ if (ref->base_alias_set != -1)
+ return ref->base_alias_set;
+ if (!ref->ref)
+ return 0;
+ base_ref = ref->ref;
+ while (handled_component_p (base_ref))
+ base_ref = TREE_OPERAND (base_ref, 0);
+ ref->base_alias_set = get_alias_set (base_ref);
+ return ref->base_alias_set;
+}
+
+/* Returns the reference alias set of the memory reference *REF. */
+
+alias_set_type
+ao_ref_alias_set (ao_ref *ref)
+{
+ if (ref->ref_alias_set != -1)
+ return ref->ref_alias_set;
+ ref->ref_alias_set = get_alias_set (ref->ref);
+ return ref->ref_alias_set;
+}
+
+/* Init an alias-oracle reference representation from a gimple pointer
+ PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the
+ size is assumed to be unknown. The access is assumed to be only
+ to or after of the pointer target, not before it. */
+
+void
+ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size)
+{
+ HOST_WIDE_INT t1, t2;
+ ref->ref = NULL_TREE;
+ if (TREE_CODE (ptr) == ADDR_EXPR)
+ ref->base = get_ref_base_and_extent (TREE_OPERAND (ptr, 0),
+ &ref->offset, &t1, &t2);
+ else
+ {
+ ref->base = build2 (MEM_REF, char_type_node,
+ ptr, null_pointer_node);
+ ref->offset = 0;
+ }
+ if (size
+ && host_integerp (size, 0)
+ && TREE_INT_CST_LOW (size) * 8 / 8 == TREE_INT_CST_LOW (size))
+ ref->max_size = ref->size = TREE_INT_CST_LOW (size) * 8;
+ else
+ ref->max_size = ref->size = -1;
+ ref->ref_alias_set = 0;
+ ref->base_alias_set = 0;
+ ref->volatile_p = false;
+}
+
/* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
decide. */
if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2))
return 1;
- /* ??? Array types are not properly unified in all cases as we have
+ /* ??? Array types are not properly unified in all cases as we have
spurious changes in the index types for example. Removing this
causes all sorts of problems with the Fortran frontend. */
if (TREE_CODE (type1) == ARRAY_TYPE
&& TREE_CODE (type2) == ARRAY_TYPE)
return -1;
+ /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
+ object of one of its constrained subtypes, e.g. when a function with an
+ unconstrained parameter passed by reference is called on an object and
+ inlined. But, even in the case of a fixed size, type and subtypes are
+ not equivalent enough as to share the same TYPE_CANONICAL, since this
+ would mean that conversions between them are useless, whereas they are
+ not (e.g. type and subtypes can have different modes). So, in the end,
+ they are only guaranteed to have the same alias set. */
+ if (get_alias_set (type1) == get_alias_set (type2))
+ return -1;
+
/* The types are known to be not equal. */
return 0;
}
/* Determine if the two component references REF1 and REF2 which are
based on access types TYPE1 and TYPE2 and of which at least one is based
- on an indirect reference may alias. */
+ on an indirect reference may alias. REF2 is the only one that can
+ be a decl in which case REF2_IS_DECL is true.
+ REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
+ are the respective alias sets. */
static bool
-nonaliasing_component_refs_p (tree ref1, tree type1,
- HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
- tree ref2, tree type2,
- HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2)
+aliasing_component_refs_p (tree ref1,
+ alias_set_type ref1_alias_set,
+ alias_set_type base1_alias_set,
+ HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
+ tree ref2,
+ alias_set_type ref2_alias_set,
+ alias_set_type base2_alias_set,
+ HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
+ bool ref2_is_decl)
{
/* If one reference is a component references through pointers try to find a
common base and apply offset based disambiguation. This handles
struct A { int i; int j; } *q;
struct B { struct A a; int k; } *p;
disambiguating q->i and p->a.j. */
+ tree base1, base2;
+ tree type1, type2;
tree *refp;
int same_p;
+ /* Choose bases and base types to search for. */
+ base1 = ref1;
+ while (handled_component_p (base1))
+ base1 = TREE_OPERAND (base1, 0);
+ type1 = TREE_TYPE (base1);
+ base2 = ref2;
+ while (handled_component_p (base2))
+ base2 = TREE_OPERAND (base2, 0);
+ type2 = TREE_TYPE (base2);
+
/* Now search for the type1 in the access path of ref2. This
would be a common base for doing offset based disambiguation on. */
- /* Skip the outermost ref - we would have caught that earlier. */
- refp = &TREE_OPERAND (ref2, 0);
+ refp = &ref2;
while (handled_component_p (*refp)
&& same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0)
refp = &TREE_OPERAND (*refp, 0);
HOST_WIDE_INT offadj, sztmp, msztmp;
get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
offset2 -= offadj;
+ get_ref_base_and_extent (base1, &offadj, &sztmp, &msztmp);
+ offset1 -= offadj;
return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
}
/* If we didn't find a common base, try the other way around. */
- refp = &TREE_OPERAND (ref1, 0);
+ refp = &ref1;
while (handled_component_p (*refp)
&& same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0)
refp = &TREE_OPERAND (*refp, 0);
HOST_WIDE_INT offadj, sztmp, msztmp;
get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp);
offset1 -= offadj;
+ get_ref_base_and_extent (base2, &offadj, &sztmp, &msztmp);
+ offset2 -= offadj;
return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
}
+
/* If we have two type access paths B1.path1 and B2.path2 they may
- only alias if either B1 is in B2.path2 or B2 is in B1.path1. */
+ only alias if either B1 is in B2.path2 or B2 is in B1.path1.
+ But we can still have a path that goes B1.path1...B2.path2 with
+ a part that we do not see. So we can only disambiguate now
+ if there is no B2 in the tail of path1 and no B1 on the
+ tail of path2. */
+ if (base1_alias_set == ref2_alias_set
+ || alias_set_subset_of (base1_alias_set, ref2_alias_set))
+ return true;
+ /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
+ if (!ref2_is_decl)
+ return (base2_alias_set == ref1_alias_set
+ || alias_set_subset_of (base2_alias_set, ref1_alias_set));
return false;
}
/* Return true if two memory references based on the variables BASE1
- and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1[ and
- [OFFSET2, OFFSET2 + MAX_SIZE2[ may alias. */
+ and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
+ [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. */
static bool
decl_refs_may_alias_p (tree base1,
tree base2,
HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2)
{
- gcc_assert (SSA_VAR_P (base1) && SSA_VAR_P (base2));
+ gcc_checking_assert (DECL_P (base1) && DECL_P (base2));
/* If both references are based on different variables, they cannot alias. */
- if (!operand_equal_p (base1, base2, 0))
+ if (base1 != base2)
return false;
/* If both references are based on the same variable, they cannot alias if
}
/* Return true if an indirect reference based on *PTR1 constrained
- to [OFFSET1, OFFSET1 + MAX_SIZE1[ may alias a variable based on BASE2
- constrained to [OFFSET2, OFFSET2 + MAX_SIZE2[. *PTR1 and BASE2 have
+ to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
+ constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
in which case they are computed on-demand. REF1 and REF2
if non-NULL are the complete memory reference trees. */
static bool
-indirect_ref_may_alias_decl_p (tree ref1, tree ptr1,
- HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
+indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
+ HOST_WIDE_INT offset1,
+ HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED,
+ alias_set_type ref1_alias_set,
alias_set_type base1_alias_set,
- tree ref2, tree base2,
+ tree ref2 ATTRIBUTE_UNUSED, tree base2,
HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
- alias_set_type base2_alias_set)
+ alias_set_type ref2_alias_set,
+ alias_set_type base2_alias_set, bool tbaa_p)
{
+ tree ptr1;
+ tree ptrtype1, dbase2;
+ HOST_WIDE_INT offset1p = offset1, offset2p = offset2;
+ HOST_WIDE_INT doffset1, doffset2;
+ double_int moff;
+
+ gcc_checking_assert ((TREE_CODE (base1) == MEM_REF
+ || TREE_CODE (base1) == TARGET_MEM_REF)
+ && DECL_P (base2));
+
+ ptr1 = TREE_OPERAND (base1, 0);
+
+ /* The offset embedded in MEM_REFs can be negative. Bias them
+ so that the resulting offset adjustment is positive. */
+ moff = mem_ref_offset (base1);
+ moff = double_int_lshift (moff,
+ BITS_PER_UNIT == 8
+ ? 3 : exact_log2 (BITS_PER_UNIT),
+ HOST_BITS_PER_DOUBLE_INT, true);
+ if (double_int_negative_p (moff))
+ offset2p += double_int_neg (moff).low;
+ else
+ offset1p += moff.low;
+
/* If only one reference is based on a variable, they cannot alias if
the pointer access is beyond the extent of the variable access.
(the pointer base cannot validly point to an offset less than zero
of the variable).
- They also cannot alias if the pointer may not point to the decl. */
- if (max_size2 != -1
- && !ranges_overlap_p (offset1, max_size1, 0, offset2 + max_size2))
+ ??? IVOPTs creates bases that do not honor this restriction,
+ so do not apply this optimization for TARGET_MEM_REFs. */
+ if (TREE_CODE (base1) != TARGET_MEM_REF
+ && !ranges_overlap_p (MAX (0, offset1p), -1, offset2p, max_size2))
return false;
+ /* They also cannot alias if the pointer may not point to the decl. */
if (!ptr_deref_may_alias_decl_p (ptr1, base2))
return false;
/* Disambiguations that rely on strict aliasing rules follow. */
- if (!flag_strict_aliasing)
+ if (!flag_strict_aliasing || !tbaa_p)
return true;
+ ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1));
+
/* If the alias set for a pointer access is zero all bets are off. */
if (base1_alias_set == -1)
- base1_alias_set = get_deref_alias_set (ptr1);
+ base1_alias_set = get_deref_alias_set (ptrtype1);
if (base1_alias_set == 0)
return true;
if (base2_alias_set == -1)
base2_alias_set = get_alias_set (base2);
- /* If both references are through the same type, they do not alias
- if the accesses do not overlap. This does extra disambiguation
- for mixed/pointer accesses but requires strict aliasing. */
- if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)),
- TREE_TYPE (base2)) == 1)
- return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
-
- /* The only way to access a variable is through a pointer dereference
- of the same alias set or a subset of it. */
+ /* When we are trying to disambiguate an access with a pointer dereference
+ as base versus one with a decl as base we can use both the size
+ of the decl and its dynamic type for extra disambiguation.
+ ??? We do not know anything about the dynamic type of the decl
+ other than that its alias-set contains base2_alias_set as a subset
+ which does not help us here. */
+ /* As we know nothing useful about the dynamic type of the decl just
+ use the usual conflict check rather than a subset test.
+ ??? We could introduce -fvery-strict-aliasing when the language
+ does not allow decls to have a dynamic type that differs from their
+ static type. Then we can check
+ !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
if (base1_alias_set != base2_alias_set
- && !alias_set_subset_of (base1_alias_set, base2_alias_set))
+ && !alias_sets_conflict_p (base1_alias_set, base2_alias_set))
+ return false;
+ /* If the size of the access relevant for TBAA through the pointer
+ is bigger than the size of the decl we can't possibly access the
+ decl via that pointer. */
+ if (DECL_SIZE (base2) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1))
+ && TREE_CODE (DECL_SIZE (base2)) == INTEGER_CST
+ && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1))) == INTEGER_CST
+ /* ??? This in turn may run afoul when a decl of type T which is
+ a member of union type U is accessed through a pointer to
+ type U and sizeof T is smaller than sizeof U. */
+ && TREE_CODE (TREE_TYPE (ptrtype1)) != UNION_TYPE
+ && TREE_CODE (TREE_TYPE (ptrtype1)) != QUAL_UNION_TYPE
+ && tree_int_cst_lt (DECL_SIZE (base2), TYPE_SIZE (TREE_TYPE (ptrtype1))))
return false;
+ if (!ref2)
+ return true;
+
+ /* If the decl is accessed via a MEM_REF, reconstruct the base
+ we can use for TBAA and an appropriately adjusted offset. */
+ dbase2 = ref2;
+ while (handled_component_p (dbase2))
+ dbase2 = TREE_OPERAND (dbase2, 0);
+ doffset1 = offset1;
+ doffset2 = offset2;
+ if (TREE_CODE (dbase2) == MEM_REF
+ || TREE_CODE (dbase2) == TARGET_MEM_REF)
+ {
+ double_int moff = mem_ref_offset (dbase2);
+ moff = double_int_lshift (moff,
+ BITS_PER_UNIT == 8
+ ? 3 : exact_log2 (BITS_PER_UNIT),
+ HOST_BITS_PER_DOUBLE_INT, true);
+ if (double_int_negative_p (moff))
+ doffset1 -= double_int_neg (moff).low;
+ else
+ doffset2 -= moff.low;
+ }
+
+ /* If either reference is view-converted, give up now. */
+ if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1
+ || same_type_for_tbaa (TREE_TYPE (dbase2), TREE_TYPE (base2)) != 1)
+ return true;
+
+ /* If both references are through the same type, they do not alias
+ if the accesses do not overlap. This does extra disambiguation
+ for mixed/pointer accesses but requires strict aliasing.
+ For MEM_REFs we require that the component-ref offset we computed
+ is relative to the start of the type which we ensure by
+ comparing rvalue and access type and disregarding the constant
+ pointer offset. */
+ if ((TREE_CODE (base1) != TARGET_MEM_REF
+ || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1)))
+ && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (dbase2)) == 1)
+ return ranges_overlap_p (doffset1, max_size1, doffset2, max_size2);
+
/* Do access-path based disambiguation. */
if (ref1 && ref2
- && handled_component_p (ref1)
- && handled_component_p (ref2))
- return nonaliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)),
- offset1, max_size1,
- ref2, TREE_TYPE (base2),
- offset2, max_size2);
+ && (handled_component_p (ref1) || handled_component_p (ref2)))
+ return aliasing_component_refs_p (ref1,
+ ref1_alias_set, base1_alias_set,
+ offset1, max_size1,
+ ref2,
+ ref2_alias_set, base2_alias_set,
+ offset2, max_size2, true);
return true;
}
/* Return true if two indirect references based on *PTR1
- and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1[ and
- [OFFSET2, OFFSET2 + MAX_SIZE2[ may alias. *PTR1 and *PTR2 have
+ and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
+ [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
in which case they are computed on-demand. REF1 and REF2
if non-NULL are the complete memory reference trees. */
static bool
-indirect_refs_may_alias_p (tree ref1, tree ptr1,
+indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1,
+ alias_set_type ref1_alias_set,
alias_set_type base1_alias_set,
- tree ref2, tree ptr2,
+ tree ref2 ATTRIBUTE_UNUSED, tree base2,
HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2,
- alias_set_type base2_alias_set)
+ alias_set_type ref2_alias_set,
+ alias_set_type base2_alias_set, bool tbaa_p)
{
+ tree ptr1;
+ tree ptr2;
+ tree ptrtype1, ptrtype2;
+
+ gcc_checking_assert ((TREE_CODE (base1) == MEM_REF
+ || TREE_CODE (base1) == TARGET_MEM_REF)
+ && (TREE_CODE (base2) == MEM_REF
+ || TREE_CODE (base2) == TARGET_MEM_REF));
+
+ ptr1 = TREE_OPERAND (base1, 0);
+ ptr2 = TREE_OPERAND (base2, 0);
+
/* If both bases are based on pointers they cannot alias if they may not
point to the same memory object or if they point to the same object
and the accesses do not overlap. */
- if (operand_equal_p (ptr1, ptr2, 0))
- return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
+ if ((!cfun || gimple_in_ssa_p (cfun))
+ && operand_equal_p (ptr1, ptr2, 0)
+ && (((TREE_CODE (base1) != TARGET_MEM_REF
+ || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1)))
+ && (TREE_CODE (base2) != TARGET_MEM_REF
+ || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2))))
+ || (TREE_CODE (base1) == TARGET_MEM_REF
+ && TREE_CODE (base2) == TARGET_MEM_REF
+ && (TMR_STEP (base1) == TMR_STEP (base2)
+ || (TMR_STEP (base1) && TMR_STEP (base2)
+ && operand_equal_p (TMR_STEP (base1),
+ TMR_STEP (base2), 0)))
+ && (TMR_INDEX (base1) == TMR_INDEX (base2)
+ || (TMR_INDEX (base1) && TMR_INDEX (base2)
+ && operand_equal_p (TMR_INDEX (base1),
+ TMR_INDEX (base2), 0)))
+ && (TMR_INDEX2 (base1) == TMR_INDEX2 (base2)
+ || (TMR_INDEX2 (base1) && TMR_INDEX2 (base2)
+ && operand_equal_p (TMR_INDEX2 (base1),
+ TMR_INDEX2 (base2), 0))))))
+ {
+ double_int moff;
+ /* The offset embedded in MEM_REFs can be negative. Bias them
+ so that the resulting offset adjustment is positive. */
+ moff = mem_ref_offset (base1);
+ moff = double_int_lshift (moff,
+ BITS_PER_UNIT == 8
+ ? 3 : exact_log2 (BITS_PER_UNIT),
+ HOST_BITS_PER_DOUBLE_INT, true);
+ if (double_int_negative_p (moff))
+ offset2 += double_int_neg (moff).low;
+ else
+ offset1 += moff.low;
+ moff = mem_ref_offset (base2);
+ moff = double_int_lshift (moff,
+ BITS_PER_UNIT == 8
+ ? 3 : exact_log2 (BITS_PER_UNIT),
+ HOST_BITS_PER_DOUBLE_INT, true);
+ if (double_int_negative_p (moff))
+ offset1 += double_int_neg (moff).low;
+ else
+ offset2 += moff.low;
+ return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
+ }
if (!ptr_derefs_may_alias_p (ptr1, ptr2))
return false;
/* Disambiguations that rely on strict aliasing rules follow. */
- if (!flag_strict_aliasing)
+ if (!flag_strict_aliasing || !tbaa_p)
return true;
+ ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1));
+ ptrtype2 = TREE_TYPE (TREE_OPERAND (base2, 1));
+
/* If the alias set for a pointer access is zero all bets are off. */
if (base1_alias_set == -1)
- base1_alias_set = get_deref_alias_set (ptr1);
+ base1_alias_set = get_deref_alias_set (ptrtype1);
if (base1_alias_set == 0)
return true;
if (base2_alias_set == -1)
- base2_alias_set = get_deref_alias_set (ptr2);
+ base2_alias_set = get_deref_alias_set (ptrtype2);
if (base2_alias_set == 0)
return true;
/* If both references are through the same type, they do not alias
if the accesses do not overlap. This does extra disambiguation
for mixed/pointer accesses but requires strict aliasing. */
- if (same_type_for_tbaa (TREE_TYPE (TREE_TYPE (ptr1)),
- TREE_TYPE (TREE_TYPE (ptr2))) == 1)
+ if ((TREE_CODE (base1) != TARGET_MEM_REF
+ || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1)))
+ && (TREE_CODE (base2) != TARGET_MEM_REF
+ || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2)))
+ && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1
+ && same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1
+ && same_type_for_tbaa (TREE_TYPE (ptrtype1),
+ TREE_TYPE (ptrtype2)) == 1)
return ranges_overlap_p (offset1, max_size1, offset2, max_size2);
/* Do type-based disambiguation. */
/* Do access-path based disambiguation. */
if (ref1 && ref2
- && handled_component_p (ref1)
- && handled_component_p (ref2))
- return nonaliasing_component_refs_p (ref1, TREE_TYPE (TREE_TYPE (ptr1)),
- offset1, max_size1,
- ref2, TREE_TYPE (TREE_TYPE (ptr2)),
- offset2, max_size2);
+ && (handled_component_p (ref1) || handled_component_p (ref2))
+ && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1
+ && same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1)
+ return aliasing_component_refs_p (ref1,
+ ref1_alias_set, base1_alias_set,
+ offset1, max_size1,
+ ref2,
+ ref2_alias_set, base2_alias_set,
+ offset2, max_size2, false);
return true;
}
/* Return true, if the two memory references REF1 and REF2 may alias. */
-static bool
-refs_may_alias_p_1 (tree ref1, tree ref2, bool tbaa_p)
+bool
+refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
{
tree base1, base2;
HOST_WIDE_INT offset1 = 0, offset2 = 0;
- HOST_WIDE_INT size1 = -1, size2 = -1;
HOST_WIDE_INT max_size1 = -1, max_size2 = -1;
bool var1_p, var2_p, ind1_p, ind2_p;
- alias_set_type set;
- gcc_assert ((SSA_VAR_P (ref1)
- || handled_component_p (ref1)
- || INDIRECT_REF_P (ref1)
- || TREE_CODE (ref1) == TARGET_MEM_REF)
- && (SSA_VAR_P (ref2)
- || handled_component_p (ref2)
- || INDIRECT_REF_P (ref2)
- || TREE_CODE (ref2) == TARGET_MEM_REF));
+ gcc_checking_assert ((!ref1->ref
+ || TREE_CODE (ref1->ref) == SSA_NAME
+ || DECL_P (ref1->ref)
+ || TREE_CODE (ref1->ref) == STRING_CST
+ || handled_component_p (ref1->ref)
+ || TREE_CODE (ref1->ref) == MEM_REF
+ || TREE_CODE (ref1->ref) == TARGET_MEM_REF)
+ && (!ref2->ref
+ || TREE_CODE (ref2->ref) == SSA_NAME
+ || DECL_P (ref2->ref)
+ || TREE_CODE (ref2->ref) == STRING_CST
+ || handled_component_p (ref2->ref)
+ || TREE_CODE (ref2->ref) == MEM_REF
+ || TREE_CODE (ref2->ref) == TARGET_MEM_REF));
/* Decompose the references into their base objects and the access. */
- base1 = get_ref_base_and_extent (ref1, &offset1, &size1, &max_size1);
- base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &max_size2);
+ base1 = ao_ref_base (ref1);
+ offset1 = ref1->offset;
+ max_size1 = ref1->max_size;
+ base2 = ao_ref_base (ref2);
+ offset2 = ref2->offset;
+ max_size2 = ref2->max_size;
/* We can end up with registers or constants as bases for example from
*D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
which is seen as a struct copy. */
if (TREE_CODE (base1) == SSA_NAME
+ || TREE_CODE (base1) == CONST_DECL
+ || TREE_CODE (base1) == CONSTRUCTOR
+ || TREE_CODE (base1) == ADDR_EXPR
+ || CONSTANT_CLASS_P (base1)
|| TREE_CODE (base2) == SSA_NAME
- || is_gimple_min_invariant (base1)
- || is_gimple_min_invariant (base2))
+ || TREE_CODE (base2) == CONST_DECL
+ || TREE_CODE (base2) == CONSTRUCTOR
+ || TREE_CODE (base2) == ADDR_EXPR
+ || CONSTANT_CLASS_P (base2))
return false;
+ /* We can end up refering to code via function and label decls.
+ As we likely do not properly track code aliases conservatively
+ bail out. */
+ if (TREE_CODE (base1) == FUNCTION_DECL
+ || TREE_CODE (base1) == LABEL_DECL
+ || TREE_CODE (base2) == FUNCTION_DECL
+ || TREE_CODE (base2) == LABEL_DECL)
+ return true;
+
+ /* Two volatile accesses always conflict. */
+ if (ref1->volatile_p
+ && ref2->volatile_p)
+ return true;
+
/* Defer to simple offset based disambiguation if we have
references based on two decls. Do this before defering to
TBAA to handle must-alias cases in conformance with the
GCC extension of allowing type-punning through unions. */
- var1_p = SSA_VAR_P (base1);
- var2_p = SSA_VAR_P (base2);
+ var1_p = DECL_P (base1);
+ var2_p = DECL_P (base2);
if (var1_p && var2_p)
return decl_refs_may_alias_p (base1, offset1, max_size1,
base2, offset2, max_size2);
+ ind1_p = (TREE_CODE (base1) == MEM_REF
+ || TREE_CODE (base1) == TARGET_MEM_REF);
+ ind2_p = (TREE_CODE (base2) == MEM_REF
+ || TREE_CODE (base2) == TARGET_MEM_REF);
+
+ /* Canonicalize the pointer-vs-decl case. */
+ if (ind1_p && var2_p)
+ {
+ HOST_WIDE_INT tmp1;
+ tree tmp2;
+ ao_ref *tmp3;
+ tmp1 = offset1; offset1 = offset2; offset2 = tmp1;
+ tmp1 = max_size1; max_size1 = max_size2; max_size2 = tmp1;
+ tmp2 = base1; base1 = base2; base2 = tmp2;
+ tmp3 = ref1; ref1 = ref2; ref2 = tmp3;
+ var1_p = true;
+ ind1_p = false;
+ var2_p = false;
+ ind2_p = true;
+ }
+
/* First defer to TBAA if possible. */
if (tbaa_p
&& flag_strict_aliasing
- && !alias_sets_conflict_p (get_alias_set (ref1), get_alias_set (ref2)))
+ && !alias_sets_conflict_p (ao_ref_alias_set (ref1),
+ ao_ref_alias_set (ref2)))
return false;
- /* If one reference is a TARGET_MEM_REF weird things are allowed. Still
- TBAA disambiguation based on the access type is possible, so bail
- out only after that check. */
- if (TREE_CODE (ref1) == TARGET_MEM_REF
- || TREE_CODE (ref2) == TARGET_MEM_REF)
- return true;
-
/* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
- ind1_p = INDIRECT_REF_P (base1);
- ind2_p = INDIRECT_REF_P (base2);
- set = tbaa_p ? -1 : 0;
if (var1_p && ind2_p)
- return indirect_ref_may_alias_decl_p (ref2, TREE_OPERAND (base2, 0),
- offset2, max_size2, set,
- ref1, base1,
- offset1, max_size1, set);
- else if (ind1_p && var2_p)
- return indirect_ref_may_alias_decl_p (ref1, TREE_OPERAND (base1, 0),
- offset1, max_size1, set,
- ref2, base2,
- offset2, max_size2, set);
+ return indirect_ref_may_alias_decl_p (ref2->ref, base2,
+ offset2, max_size2,
+ ao_ref_alias_set (ref2), -1,
+ ref1->ref, base1,
+ offset1, max_size1,
+ ao_ref_alias_set (ref1),
+ ao_ref_base_alias_set (ref1),
+ tbaa_p);
else if (ind1_p && ind2_p)
- return indirect_refs_may_alias_p (ref1, TREE_OPERAND (base1, 0),
- offset1, max_size1, set,
- ref2, TREE_OPERAND (base2, 0),
- offset2, max_size2, set);
-
+ return indirect_refs_may_alias_p (ref1->ref, base1,
+ offset1, max_size1,
+ ao_ref_alias_set (ref1), -1,
+ ref2->ref, base2,
+ offset2, max_size2,
+ ao_ref_alias_set (ref2), -1,
+ tbaa_p);
+
+ /* We really do not want to end up here, but returning true is safe. */
+#ifdef ENABLE_CHECKING
gcc_unreachable ();
+#else
+ return true;
+#endif
}
bool
refs_may_alias_p (tree ref1, tree ref2)
{
- bool res = refs_may_alias_p_1 (ref1, ref2, true);
+ ao_ref r1, r2;
+ bool res;
+ ao_ref_init (&r1, ref1);
+ ao_ref_init (&r2, ref2);
+ res = refs_may_alias_p_1 (&r1, &r2, true);
if (res)
++alias_stats.refs_may_alias_p_may_alias;
else
bool
refs_anti_dependent_p (tree load, tree store)
{
- return refs_may_alias_p_1 (load, store, false);
+ ao_ref r1, r2;
+ ao_ref_init (&r1, load);
+ ao_ref_init (&r2, store);
+ return refs_may_alias_p_1 (&r1, &r2, false);
}
/* Returns true if there is a output dependence for the stores
bool
refs_output_dependent_p (tree store1, tree store2)
{
- return refs_may_alias_p_1 (store1, store2, false);
+ ao_ref r1, r2;
+ ao_ref_init (&r1, store1);
+ ao_ref_init (&r2, store2);
+ return refs_may_alias_p_1 (&r1, &r2, false);
}
/* If the call CALL may use the memory reference REF return true,
otherwise return false. */
static bool
-ref_maybe_used_by_call_p_1 (gimple call, tree ref)
+ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
{
- tree base;
+ tree base, callee;
unsigned i;
int flags = gimple_call_flags (call);
&& (flags & (ECF_CONST|ECF_NOVOPS)))
goto process_args;
- /* If the reference is not based on a decl give up.
- ??? Handle indirect references by intersecting the call-used
- solution with that of the pointer. */
- base = get_base_address (ref);
- if (!base
- || !DECL_P (base))
+ base = ao_ref_base (ref);
+ if (!base)
+ return true;
+
+ /* A call that is not without side-effects might involve volatile
+ accesses and thus conflicts with all other volatile accesses. */
+ if (ref->volatile_p)
return true;
/* If the reference is based on a decl that is not aliased the call
&& !is_global_var (base))
goto process_args;
+ callee = gimple_call_fndecl (call);
+
+ /* Handle those builtin functions explicitly that do not act as
+ escape points. See tree-ssa-structalias.c:find_func_aliases
+ for the list of builtins we might need to handle here. */
+ if (callee != NULL_TREE
+ && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ /* All the following functions read memory pointed to by
+ their second argument. strcat/strncat additionally
+ reads memory pointed to by the first argument. */
+ case BUILT_IN_STRCAT:
+ case BUILT_IN_STRNCAT:
+ {
+ ao_ref dref;
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ NULL_TREE);
+ if (refs_may_alias_p_1 (&dref, ref, false))
+ return true;
+ }
+ /* FALLTHRU */
+ case BUILT_IN_STRCPY:
+ case BUILT_IN_STRNCPY:
+ case BUILT_IN_MEMCPY:
+ case BUILT_IN_MEMMOVE:
+ case BUILT_IN_MEMPCPY:
+ case BUILT_IN_STPCPY:
+ case BUILT_IN_STPNCPY:
+ case BUILT_IN_TM_MEMCPY:
+ case BUILT_IN_TM_MEMMOVE:
+ {
+ ao_ref dref;
+ tree size = NULL_TREE;
+ if (gimple_call_num_args (call) == 3)
+ size = gimple_call_arg (call, 2);
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 1),
+ size);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ case BUILT_IN_STRCAT_CHK:
+ case BUILT_IN_STRNCAT_CHK:
+ {
+ ao_ref dref;
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ NULL_TREE);
+ if (refs_may_alias_p_1 (&dref, ref, false))
+ return true;
+ }
+ /* FALLTHRU */
+ case BUILT_IN_STRCPY_CHK:
+ case BUILT_IN_STRNCPY_CHK:
+ case BUILT_IN_MEMCPY_CHK:
+ case BUILT_IN_MEMMOVE_CHK:
+ case BUILT_IN_MEMPCPY_CHK:
+ case BUILT_IN_STPCPY_CHK:
+ case BUILT_IN_STPNCPY_CHK:
+ {
+ ao_ref dref;
+ tree size = NULL_TREE;
+ if (gimple_call_num_args (call) == 4)
+ size = gimple_call_arg (call, 2);
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 1),
+ size);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ case BUILT_IN_BCOPY:
+ {
+ ao_ref dref;
+ tree size = gimple_call_arg (call, 2);
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ size);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+
+ /* The following functions read memory pointed to by their
+ first argument. */
+ CASE_BUILT_IN_TM_LOAD (1):
+ CASE_BUILT_IN_TM_LOAD (2):
+ CASE_BUILT_IN_TM_LOAD (4):
+ CASE_BUILT_IN_TM_LOAD (8):
+ CASE_BUILT_IN_TM_LOAD (FLOAT):
+ CASE_BUILT_IN_TM_LOAD (DOUBLE):
+ CASE_BUILT_IN_TM_LOAD (LDOUBLE):
+ CASE_BUILT_IN_TM_LOAD (M64):
+ CASE_BUILT_IN_TM_LOAD (M128):
+ CASE_BUILT_IN_TM_LOAD (M256):
+ case BUILT_IN_TM_LOG:
+ case BUILT_IN_TM_LOG_1:
+ case BUILT_IN_TM_LOG_2:
+ case BUILT_IN_TM_LOG_4:
+ case BUILT_IN_TM_LOG_8:
+ case BUILT_IN_TM_LOG_FLOAT:
+ case BUILT_IN_TM_LOG_DOUBLE:
+ case BUILT_IN_TM_LOG_LDOUBLE:
+ case BUILT_IN_TM_LOG_M64:
+ case BUILT_IN_TM_LOG_M128:
+ case BUILT_IN_TM_LOG_M256:
+ return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call, 0), ref);
+
+ /* These read memory pointed to by the first argument. */
+ case BUILT_IN_STRDUP:
+ case BUILT_IN_STRNDUP:
+ {
+ ao_ref dref;
+ tree size = NULL_TREE;
+ if (gimple_call_num_args (call) == 2)
+ size = gimple_call_arg (call, 1);
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ size);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ /* The following builtins do not read from memory. */
+ case BUILT_IN_FREE:
+ case BUILT_IN_MALLOC:
+ case BUILT_IN_CALLOC:
+ case BUILT_IN_ALLOCA:
+ case BUILT_IN_ALLOCA_WITH_ALIGN:
+ case BUILT_IN_STACK_SAVE:
+ case BUILT_IN_STACK_RESTORE:
+ case BUILT_IN_MEMSET:
+ case BUILT_IN_TM_MEMSET:
+ case BUILT_IN_MEMSET_CHK:
+ case BUILT_IN_FREXP:
+ case BUILT_IN_FREXPF:
+ case BUILT_IN_FREXPL:
+ case BUILT_IN_GAMMA_R:
+ case BUILT_IN_GAMMAF_R:
+ case BUILT_IN_GAMMAL_R:
+ case BUILT_IN_LGAMMA_R:
+ case BUILT_IN_LGAMMAF_R:
+ case BUILT_IN_LGAMMAL_R:
+ case BUILT_IN_MODF:
+ case BUILT_IN_MODFF:
+ case BUILT_IN_MODFL:
+ case BUILT_IN_REMQUO:
+ case BUILT_IN_REMQUOF:
+ case BUILT_IN_REMQUOL:
+ case BUILT_IN_SINCOS:
+ case BUILT_IN_SINCOSF:
+ case BUILT_IN_SINCOSL:
+ case BUILT_IN_ASSUME_ALIGNED:
+ case BUILT_IN_VA_END:
+ return false;
+ /* __sync_* builtins and some OpenMP builtins act as threading
+ barriers. */
+#undef DEF_SYNC_BUILTIN
+#define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
+#include "sync-builtins.def"
+#undef DEF_SYNC_BUILTIN
+ case BUILT_IN_GOMP_ATOMIC_START:
+ case BUILT_IN_GOMP_ATOMIC_END:
+ case BUILT_IN_GOMP_BARRIER:
+ case BUILT_IN_GOMP_TASKWAIT:
+ case BUILT_IN_GOMP_CRITICAL_START:
+ case BUILT_IN_GOMP_CRITICAL_END:
+ case BUILT_IN_GOMP_CRITICAL_NAME_START:
+ case BUILT_IN_GOMP_CRITICAL_NAME_END:
+ case BUILT_IN_GOMP_LOOP_END:
+ case BUILT_IN_GOMP_ORDERED_START:
+ case BUILT_IN_GOMP_ORDERED_END:
+ case BUILT_IN_GOMP_PARALLEL_END:
+ case BUILT_IN_GOMP_SECTIONS_END:
+ case BUILT_IN_GOMP_SINGLE_COPY_START:
+ case BUILT_IN_GOMP_SINGLE_COPY_END:
+ return true;
+
+ default:
+ /* Fallthru to general call handling. */;
+ }
+
/* Check if base is a global static variable that is not read
by the function. */
- if (TREE_CODE (base) == VAR_DECL
- && TREE_STATIC (base)
- && !TREE_PUBLIC (base))
+ if (callee != NULL_TREE
+ && TREE_CODE (base) == VAR_DECL
+ && TREE_STATIC (base))
{
- tree callee = gimple_call_fndecl (call);
+ struct cgraph_node *node = cgraph_get_node (callee);
bitmap not_read;
- if (callee != NULL_TREE
- && (not_read
- = ipa_reference_get_not_read_global (cgraph_node (callee)))
+ /* FIXME: Callee can be an OMP builtin that does not have a call graph
+ node yet. We should enforce that there are nodes for all decls in the
+ IL and remove this check instead. */
+ if (node
+ && (not_read = ipa_reference_get_not_read_global (node))
&& bitmap_bit_p (not_read, DECL_UID (base)))
goto process_args;
}
- /* If the base variable is call-used or call-clobbered then
- it may be used. */
- if (flags & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS))
+ /* Check if the base variable is call-used. */
+ if (DECL_P (base))
{
- if (is_call_used (base))
+ if (pt_solution_includes (gimple_call_use_set (call), base))
return true;
}
- else
+ else if ((TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF)
+ && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
{
- if (is_call_clobbered (base))
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
+ if (!pi)
+ return true;
+
+ if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt))
return true;
}
+ else
+ return true;
/* Inspect call arguments for passed-by-value aliases. */
process_args:
for (i = 0; i < gimple_call_num_args (call); ++i)
{
tree op = gimple_call_arg (call, i);
+ int flags = gimple_call_arg_flags (call, i);
- if (TREE_CODE (op) == EXC_PTR_EXPR
- || TREE_CODE (op) == FILTER_EXPR)
+ if (flags & EAF_UNUSED)
continue;
if (TREE_CODE (op) == WITH_SIZE_EXPR)
op = TREE_OPERAND (op, 0);
if (TREE_CODE (op) != SSA_NAME
- && !is_gimple_min_invariant (op)
- && refs_may_alias_p (op, ref))
- return true;
+ && !is_gimple_min_invariant (op))
+ {
+ ao_ref r;
+ ao_ref_init (&r, op);
+ if (refs_may_alias_p_1 (&r, ref, true))
+ return true;
+ }
}
return false;
static bool
ref_maybe_used_by_call_p (gimple call, tree ref)
{
- bool res = ref_maybe_used_by_call_p_1 (call, ref);
+ ao_ref r;
+ bool res;
+ ao_ref_init (&r, ref);
+ res = ref_maybe_used_by_call_p_1 (call, &r);
if (res)
++alias_stats.ref_maybe_used_by_call_p_may_alias;
else
}
else if (is_gimple_call (stmt))
return ref_maybe_used_by_call_p (stmt, ref);
+ else if (gimple_code (stmt) == GIMPLE_RETURN)
+ {
+ tree retval = gimple_return_retval (stmt);
+ tree base;
+ if (retval
+ && TREE_CODE (retval) != SSA_NAME
+ && !is_gimple_min_invariant (retval)
+ && refs_may_alias_p (retval, ref))
+ return true;
+ /* If ref escapes the function then the return acts as a use. */
+ base = get_base_address (ref);
+ if (!base)
+ ;
+ else if (DECL_P (base))
+ return is_global_var (base);
+ else if (TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF)
+ return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0));
+ return false;
+ }
return true;
}
return true, otherwise return false. */
static bool
-call_may_clobber_ref_p_1 (gimple call, tree ref)
+call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
{
tree base;
+ tree callee;
/* If the call is pure or const it cannot clobber anything. */
if (gimple_call_flags (call)
& (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS))
return false;
- base = get_base_address (ref);
+ base = ao_ref_base (ref);
if (!base)
return true;
|| CONSTANT_CLASS_P (base))
return false;
+ /* A call that is not without side-effects might involve volatile
+ accesses and thus conflicts with all other volatile accesses. */
+ if (ref->volatile_p)
+ return true;
+
/* If the reference is based on a decl that is not aliased the call
cannot possibly clobber it. */
if (DECL_P (base)
|| !is_global_var (base)))
return false;
+ callee = gimple_call_fndecl (call);
+
+ /* Handle those builtin functions explicitly that do not act as
+ escape points. See tree-ssa-structalias.c:find_func_aliases
+ for the list of builtins we might need to handle here. */
+ if (callee != NULL_TREE
+ && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ /* All the following functions clobber memory pointed to by
+ their first argument. */
+ case BUILT_IN_STRCPY:
+ case BUILT_IN_STRNCPY:
+ case BUILT_IN_MEMCPY:
+ case BUILT_IN_MEMMOVE:
+ case BUILT_IN_MEMPCPY:
+ case BUILT_IN_STPCPY:
+ case BUILT_IN_STPNCPY:
+ case BUILT_IN_STRCAT:
+ case BUILT_IN_STRNCAT:
+ case BUILT_IN_MEMSET:
+ case BUILT_IN_TM_MEMSET:
+ CASE_BUILT_IN_TM_STORE (1):
+ CASE_BUILT_IN_TM_STORE (2):
+ CASE_BUILT_IN_TM_STORE (4):
+ CASE_BUILT_IN_TM_STORE (8):
+ CASE_BUILT_IN_TM_STORE (FLOAT):
+ CASE_BUILT_IN_TM_STORE (DOUBLE):
+ CASE_BUILT_IN_TM_STORE (LDOUBLE):
+ CASE_BUILT_IN_TM_STORE (M64):
+ CASE_BUILT_IN_TM_STORE (M128):
+ CASE_BUILT_IN_TM_STORE (M256):
+ case BUILT_IN_TM_MEMCPY:
+ case BUILT_IN_TM_MEMMOVE:
+ {
+ ao_ref dref;
+ tree size = NULL_TREE;
+ /* Don't pass in size for strncat, as the maximum size
+ is strlen (dest) + n + 1 instead of n, resp.
+ n + 1 at dest + strlen (dest), but strlen (dest) isn't
+ known. */
+ if (gimple_call_num_args (call) == 3
+ && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT)
+ size = gimple_call_arg (call, 2);
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ size);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ case BUILT_IN_STRCPY_CHK:
+ case BUILT_IN_STRNCPY_CHK:
+ case BUILT_IN_MEMCPY_CHK:
+ case BUILT_IN_MEMMOVE_CHK:
+ case BUILT_IN_MEMPCPY_CHK:
+ case BUILT_IN_STPCPY_CHK:
+ case BUILT_IN_STPNCPY_CHK:
+ case BUILT_IN_STRCAT_CHK:
+ case BUILT_IN_STRNCAT_CHK:
+ case BUILT_IN_MEMSET_CHK:
+ {
+ ao_ref dref;
+ tree size = NULL_TREE;
+ /* Don't pass in size for __strncat_chk, as the maximum size
+ is strlen (dest) + n + 1 instead of n, resp.
+ n + 1 at dest + strlen (dest), but strlen (dest) isn't
+ known. */
+ if (gimple_call_num_args (call) == 4
+ && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT_CHK)
+ size = gimple_call_arg (call, 2);
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 0),
+ size);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ case BUILT_IN_BCOPY:
+ {
+ ao_ref dref;
+ tree size = gimple_call_arg (call, 2);
+ ao_ref_init_from_ptr_and_size (&dref,
+ gimple_call_arg (call, 1),
+ size);
+ return refs_may_alias_p_1 (&dref, ref, false);
+ }
+ /* Allocating memory does not have any side-effects apart from
+ being the definition point for the pointer. */
+ case BUILT_IN_MALLOC:
+ case BUILT_IN_CALLOC:
+ case BUILT_IN_STRDUP:
+ case BUILT_IN_STRNDUP:
+ /* Unix98 specifies that errno is set on allocation failure. */
+ if (flag_errno_math
+ && targetm.ref_may_alias_errno (ref))
+ return true;
+ return false;
+ case BUILT_IN_STACK_SAVE:
+ case BUILT_IN_ALLOCA:
+ case BUILT_IN_ALLOCA_WITH_ALIGN:
+ case BUILT_IN_ASSUME_ALIGNED:
+ return false;
+ /* Freeing memory kills the pointed-to memory. More importantly
+ the call has to serve as a barrier for moving loads and stores
+ across it. */
+ case BUILT_IN_FREE:
+ case BUILT_IN_VA_END:
+ {
+ tree ptr = gimple_call_arg (call, 0);
+ return ptr_deref_may_alias_ref_p_1 (ptr, ref);
+ }
+ case BUILT_IN_GAMMA_R:
+ case BUILT_IN_GAMMAF_R:
+ case BUILT_IN_GAMMAL_R:
+ case BUILT_IN_LGAMMA_R:
+ case BUILT_IN_LGAMMAF_R:
+ case BUILT_IN_LGAMMAL_R:
+ {
+ tree out = gimple_call_arg (call, 1);
+ if (ptr_deref_may_alias_ref_p_1 (out, ref))
+ return true;
+ if (flag_errno_math)
+ break;
+ return false;
+ }
+ case BUILT_IN_FREXP:
+ case BUILT_IN_FREXPF:
+ case BUILT_IN_FREXPL:
+ case BUILT_IN_MODF:
+ case BUILT_IN_MODFF:
+ case BUILT_IN_MODFL:
+ {
+ tree out = gimple_call_arg (call, 1);
+ return ptr_deref_may_alias_ref_p_1 (out, ref);
+ }
+ case BUILT_IN_REMQUO:
+ case BUILT_IN_REMQUOF:
+ case BUILT_IN_REMQUOL:
+ {
+ tree out = gimple_call_arg (call, 2);
+ if (ptr_deref_may_alias_ref_p_1 (out, ref))
+ return true;
+ if (flag_errno_math)
+ break;
+ return false;
+ }
+ case BUILT_IN_SINCOS:
+ case BUILT_IN_SINCOSF:
+ case BUILT_IN_SINCOSL:
+ {
+ tree sin = gimple_call_arg (call, 1);
+ tree cos = gimple_call_arg (call, 2);
+ return (ptr_deref_may_alias_ref_p_1 (sin, ref)
+ || ptr_deref_may_alias_ref_p_1 (cos, ref));
+ }
+ /* __sync_* builtins and some OpenMP builtins act as threading
+ barriers. */
+#undef DEF_SYNC_BUILTIN
+#define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
+#include "sync-builtins.def"
+#undef DEF_SYNC_BUILTIN
+ case BUILT_IN_GOMP_ATOMIC_START:
+ case BUILT_IN_GOMP_ATOMIC_END:
+ case BUILT_IN_GOMP_BARRIER:
+ case BUILT_IN_GOMP_TASKWAIT:
+ case BUILT_IN_GOMP_CRITICAL_START:
+ case BUILT_IN_GOMP_CRITICAL_END:
+ case BUILT_IN_GOMP_CRITICAL_NAME_START:
+ case BUILT_IN_GOMP_CRITICAL_NAME_END:
+ case BUILT_IN_GOMP_LOOP_END:
+ case BUILT_IN_GOMP_ORDERED_START:
+ case BUILT_IN_GOMP_ORDERED_END:
+ case BUILT_IN_GOMP_PARALLEL_END:
+ case BUILT_IN_GOMP_SECTIONS_END:
+ case BUILT_IN_GOMP_SINGLE_COPY_START:
+ case BUILT_IN_GOMP_SINGLE_COPY_END:
+ return true;
+ default:
+ /* Fallthru to general call handling. */;
+ }
+
/* Check if base is a global static variable that is not written
by the function. */
- if (TREE_CODE (base) == VAR_DECL
- && TREE_STATIC (base)
- && !TREE_PUBLIC (base))
+ if (callee != NULL_TREE
+ && TREE_CODE (base) == VAR_DECL
+ && TREE_STATIC (base))
{
- tree callee = gimple_call_fndecl (call);
+ struct cgraph_node *node = cgraph_get_node (callee);
bitmap not_written;
- if (callee != NULL_TREE
- && (not_written
- = ipa_reference_get_not_written_global (cgraph_node (callee)))
+ if (node
+ && (not_written = ipa_reference_get_not_written_global (node))
&& bitmap_bit_p (not_written, DECL_UID (base)))
return false;
}
+ /* Check if the base variable is call-clobbered. */
if (DECL_P (base))
- return is_call_clobbered (base);
+ return pt_solution_includes (gimple_call_clobber_set (call), base);
+ else if ((TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF)
+ && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
+ {
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
+ if (!pi)
+ return true;
+
+ return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt);
+ }
return true;
}
-static bool
+/* If the call in statement CALL may clobber the memory reference REF
+ return true, otherwise return false. */
+
+bool
call_may_clobber_ref_p (gimple call, tree ref)
{
- bool res = call_may_clobber_ref_p_1 (call, ref);
+ bool res;
+ ao_ref r;
+ ao_ref_init (&r, ref);
+ res = call_may_clobber_ref_p_1 (call, &r);
if (res)
++alias_stats.call_may_clobber_ref_p_may_alias;
else
otherwise return false. */
bool
-stmt_may_clobber_ref_p (gimple stmt, tree ref)
+stmt_may_clobber_ref_p_1 (gimple stmt, ao_ref *ref)
{
if (is_gimple_call (stmt))
{
tree lhs = gimple_call_lhs (stmt);
if (lhs
- && !is_gimple_reg (lhs)
- && refs_may_alias_p (ref, lhs))
- return true;
+ && TREE_CODE (lhs) != SSA_NAME)
+ {
+ ao_ref r;
+ ao_ref_init (&r, lhs);
+ if (refs_may_alias_p_1 (ref, &r, true))
+ return true;
+ }
- return call_may_clobber_ref_p (stmt, ref);
+ return call_may_clobber_ref_p_1 (stmt, ref);
+ }
+ else if (gimple_assign_single_p (stmt))
+ {
+ tree lhs = gimple_assign_lhs (stmt);
+ if (TREE_CODE (lhs) != SSA_NAME)
+ {
+ ao_ref r;
+ ao_ref_init (&r, lhs);
+ return refs_may_alias_p_1 (ref, &r, true);
+ }
}
- else if (is_gimple_assign (stmt))
- return refs_may_alias_p (ref, gimple_assign_lhs (stmt));
else if (gimple_code (stmt) == GIMPLE_ASM)
return true;
return false;
}
-static tree get_continuation_for_phi (gimple, tree, bitmap *);
+bool
+stmt_may_clobber_ref_p (gimple stmt, tree ref)
+{
+ ao_ref r;
+ ao_ref_init (&r, ref);
+ return stmt_may_clobber_ref_p_1 (stmt, &r);
+}
+
+/* If STMT kills the memory reference REF return true, otherwise
+ return false. */
+
+static bool
+stmt_kills_ref_p_1 (gimple stmt, ao_ref *ref)
+{
+ /* For a must-alias check we need to be able to constrain
+ the access properly. */
+ ao_ref_base (ref);
+ if (ref->max_size == -1)
+ return false;
+
+ if (gimple_has_lhs (stmt)
+ && TREE_CODE (gimple_get_lhs (stmt)) != SSA_NAME
+ /* The assignment is not necessarily carried out if it can throw
+ and we can catch it in the current function where we could inspect
+ the previous value.
+ ??? We only need to care about the RHS throwing. For aggregate
+ assignments or similar calls and non-call exceptions the LHS
+ might throw as well. */
+ && !stmt_can_throw_internal (stmt))
+ {
+ tree base, lhs = gimple_get_lhs (stmt);
+ HOST_WIDE_INT size, offset, max_size;
+ base = get_ref_base_and_extent (lhs, &offset, &size, &max_size);
+ /* We can get MEM[symbol: sZ, index: D.8862_1] here,
+ so base == ref->base does not always hold. */
+ if (base == ref->base)
+ {
+ /* For a must-alias check we need to be able to constrain
+ the access properly. */
+ if (size != -1 && size == max_size)
+ {
+ if (offset <= ref->offset
+ && offset + size >= ref->offset + ref->max_size)
+ return true;
+ }
+ }
+ }
+
+ if (is_gimple_call (stmt))
+ {
+ tree callee = gimple_call_fndecl (stmt);
+ if (callee != NULL_TREE
+ && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ case BUILT_IN_MEMCPY:
+ case BUILT_IN_MEMPCPY:
+ case BUILT_IN_MEMMOVE:
+ case BUILT_IN_MEMSET:
+ case BUILT_IN_MEMCPY_CHK:
+ case BUILT_IN_MEMPCPY_CHK:
+ case BUILT_IN_MEMMOVE_CHK:
+ case BUILT_IN_MEMSET_CHK:
+ {
+ tree dest = gimple_call_arg (stmt, 0);
+ tree len = gimple_call_arg (stmt, 2);
+ tree base = NULL_TREE;
+ HOST_WIDE_INT offset = 0;
+ if (!host_integerp (len, 0))
+ return false;
+ if (TREE_CODE (dest) == ADDR_EXPR)
+ base = get_addr_base_and_unit_offset (TREE_OPERAND (dest, 0),
+ &offset);
+ else if (TREE_CODE (dest) == SSA_NAME)
+ base = dest;
+ if (base
+ && base == ao_ref_base (ref))
+ {
+ HOST_WIDE_INT size = TREE_INT_CST_LOW (len);
+ if (offset <= ref->offset / BITS_PER_UNIT
+ && (offset + size
+ >= ((ref->offset + ref->max_size + BITS_PER_UNIT - 1)
+ / BITS_PER_UNIT)))
+ return true;
+ }
+ break;
+ }
+
+ case BUILT_IN_VA_END:
+ {
+ tree ptr = gimple_call_arg (stmt, 0);
+ if (TREE_CODE (ptr) == ADDR_EXPR)
+ {
+ tree base = ao_ref_base (ref);
+ if (TREE_OPERAND (ptr, 0) == base)
+ return true;
+ }
+ break;
+ }
+
+ default:;
+ }
+ }
+ return false;
+}
+
+bool
+stmt_kills_ref_p (gimple stmt, tree ref)
+{
+ ao_ref r;
+ ao_ref_init (&r, ref);
+ return stmt_kills_ref_p_1 (stmt, &r);
+}
+
/* Walk the virtual use-def chain of VUSE until hitting the virtual operand
TARGET or a statement clobbering the memory reference REF in which
case false is returned. The walk starts with VUSE, one argument of PHI. */
static bool
-maybe_skip_until (gimple phi, tree target, tree ref, tree vuse, bitmap *visited)
+maybe_skip_until (gimple phi, tree target, ao_ref *ref,
+ tree vuse, bitmap *visited, bool abort_on_visited)
{
+ basic_block bb = gimple_bb (phi);
+
if (!*visited)
*visited = BITMAP_ALLOC (NULL);
{
/* An already visited PHI node ends the walk successfully. */
if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt))))
- return true;
- vuse = get_continuation_for_phi (def_stmt, ref, visited);
+ return !abort_on_visited;
+ vuse = get_continuation_for_phi (def_stmt, ref,
+ visited, abort_on_visited);
if (!vuse)
return false;
continue;
}
/* A clobbering statement or the end of the IL ends it failing. */
else if (gimple_nop_p (def_stmt)
- || stmt_may_clobber_ref_p (def_stmt, ref))
+ || stmt_may_clobber_ref_p_1 (def_stmt, ref))
return false;
+ /* If we reach a new basic-block see if we already skipped it
+ in a previous walk that ended successfully. */
+ if (gimple_bb (def_stmt) != bb)
+ {
+ if (!bitmap_set_bit (*visited, SSA_NAME_VERSION (vuse)))
+ return !abort_on_visited;
+ bb = gimple_bb (def_stmt);
+ }
vuse = gimple_vuse (def_stmt);
}
return true;
}
+/* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code
+ until we hit the phi argument definition that dominates the other one.
+ Return that, or NULL_TREE if there is no such definition. */
+
+static tree
+get_continuation_for_phi_1 (gimple phi, tree arg0, tree arg1,
+ ao_ref *ref, bitmap *visited,
+ bool abort_on_visited)
+{
+ gimple def0 = SSA_NAME_DEF_STMT (arg0);
+ gimple def1 = SSA_NAME_DEF_STMT (arg1);
+ tree common_vuse;
+
+ if (arg0 == arg1)
+ return arg0;
+ else if (gimple_nop_p (def0)
+ || (!gimple_nop_p (def1)
+ && dominated_by_p (CDI_DOMINATORS,
+ gimple_bb (def1), gimple_bb (def0))))
+ {
+ if (maybe_skip_until (phi, arg0, ref, arg1, visited, abort_on_visited))
+ return arg0;
+ }
+ else if (gimple_nop_p (def1)
+ || dominated_by_p (CDI_DOMINATORS,
+ gimple_bb (def0), gimple_bb (def1)))
+ {
+ if (maybe_skip_until (phi, arg1, ref, arg0, visited, abort_on_visited))
+ return arg1;
+ }
+ /* Special case of a diamond:
+ MEM_1 = ...
+ goto (cond) ? L1 : L2
+ L1: store1 = ... #MEM_2 = vuse(MEM_1)
+ goto L3
+ L2: store2 = ... #MEM_3 = vuse(MEM_1)
+ L3: MEM_4 = PHI<MEM_2, MEM_3>
+ We were called with the PHI at L3, MEM_2 and MEM_3 don't
+ dominate each other, but still we can easily skip this PHI node
+ if we recognize that the vuse MEM operand is the same for both,
+ and that we can skip both statements (they don't clobber us).
+ This is still linear. Don't use maybe_skip_until, that might
+ potentially be slow. */
+ else if ((common_vuse = gimple_vuse (def0))
+ && common_vuse == gimple_vuse (def1))
+ {
+ if (!stmt_may_clobber_ref_p_1 (def0, ref)
+ && !stmt_may_clobber_ref_p_1 (def1, ref))
+ return common_vuse;
+ }
+
+ return NULL_TREE;
+}
+
+
/* Starting from a PHI node for the virtual operand of the memory reference
REF find a continuation virtual operand that allows to continue walking
statements dominating PHI skipping only statements that cannot possibly
clobber REF. Returns NULL_TREE if no suitable virtual operand can
be found. */
-static tree
-get_continuation_for_phi (gimple phi, tree ref, bitmap *visited)
+tree
+get_continuation_for_phi (gimple phi, ao_ref *ref, bitmap *visited,
+ bool abort_on_visited)
{
unsigned nargs = gimple_phi_num_args (phi);
if (nargs == 1)
return PHI_ARG_DEF (phi, 0);
- /* For two arguments try to skip non-aliasing code until we hit
- the phi argument definition that dominates the other one. */
- if (nargs == 2)
+ /* For two or more arguments try to pairwise skip non-aliasing code
+ until we hit the phi argument definition that dominates the other one. */
+ else if (nargs >= 2)
{
- tree arg0 = PHI_ARG_DEF (phi, 0);
- tree arg1 = PHI_ARG_DEF (phi, 1);
- gimple def0 = SSA_NAME_DEF_STMT (arg0);
- gimple def1 = SSA_NAME_DEF_STMT (arg1);
-
- if (arg0 == arg1)
- return arg0;
- else if (gimple_nop_p (def0)
- || (!gimple_nop_p (def1)
- && dominated_by_p (CDI_DOMINATORS,
- gimple_bb (def1), gimple_bb (def0))))
+ tree arg0, arg1;
+ unsigned i;
+
+ /* Find a candidate for the virtual operand which definition
+ dominates those of all others. */
+ arg0 = PHI_ARG_DEF (phi, 0);
+ if (!SSA_NAME_IS_DEFAULT_DEF (arg0))
+ for (i = 1; i < nargs; ++i)
+ {
+ arg1 = PHI_ARG_DEF (phi, i);
+ if (SSA_NAME_IS_DEFAULT_DEF (arg1))
+ {
+ arg0 = arg1;
+ break;
+ }
+ if (dominated_by_p (CDI_DOMINATORS,
+ gimple_bb (SSA_NAME_DEF_STMT (arg0)),
+ gimple_bb (SSA_NAME_DEF_STMT (arg1))))
+ arg0 = arg1;
+ }
+
+ /* Then pairwise reduce against the found candidate. */
+ for (i = 0; i < nargs; ++i)
{
- if (maybe_skip_until (phi, arg0, ref, arg1, visited))
- return arg0;
- }
- else if (gimple_nop_p (def1)
- || dominated_by_p (CDI_DOMINATORS,
- gimple_bb (def0), gimple_bb (def1)))
- {
- if (maybe_skip_until (phi, arg1, ref, arg0, visited))
- return arg1;
+ arg1 = PHI_ARG_DEF (phi, i);
+ arg0 = get_continuation_for_phi_1 (phi, arg0, arg1, ref, visited,
+ abort_on_visited);
+ if (!arg0)
+ return NULL_TREE;
}
+
+ return arg0;
}
return NULL_TREE;
WALKER returns non-NULL the walk stops and its result is returned.
At the end of a non-successful walk NULL is returned.
+ TRANSLATE if non-NULL is called with a pointer to REF, the virtual
+ use which definition is a statement that may clobber REF and DATA.
+ If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
+ If TRANSLATE returns non-NULL the walk stops and its result is returned.
+ If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
+ to adjust REF and *DATA to make that valid.
+
TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
void *
-walk_non_aliased_vuses (tree ref, tree vuse,
- void *(*walker)(tree, tree, void *), void *data)
+walk_non_aliased_vuses (ao_ref *ref, tree vuse,
+ void *(*walker)(ao_ref *, tree, void *),
+ void *(*translate)(ao_ref *, tree, void *), void *data)
{
bitmap visited = NULL;
void *res;
+ bool translated = false;
timevar_push (TV_ALIAS_STMT_WALK);
if (gimple_nop_p (def_stmt))
break;
else if (gimple_code (def_stmt) == GIMPLE_PHI)
- vuse = get_continuation_for_phi (def_stmt, ref, &visited);
+ vuse = get_continuation_for_phi (def_stmt, ref, &visited, translated);
else
{
- if (stmt_may_clobber_ref_p (def_stmt, ref))
- break;
+ if (stmt_may_clobber_ref_p_1 (def_stmt, ref))
+ {
+ if (!translate)
+ break;
+ res = (*translate) (ref, vuse, data);
+ /* Failed lookup and translation. */
+ if (res == (void *)-1)
+ {
+ res = NULL;
+ break;
+ }
+ /* Lookup succeeded. */
+ else if (res != NULL)
+ break;
+ /* Translation succeeded, continue walking. */
+ translated = true;
+ }
vuse = gimple_vuse (def_stmt);
}
}
The function returns the number of statements walked. */
static unsigned int
-walk_aliased_vdefs_1 (tree ref, tree vdef,
- bool (*walker)(tree, tree, void *), void *data,
+walk_aliased_vdefs_1 (ao_ref *ref, tree vdef,
+ bool (*walker)(ao_ref *, tree, void *), void *data,
bitmap *visited, unsigned int cnt)
{
do
/* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
cnt++;
if ((!ref
- || stmt_may_clobber_ref_p (def_stmt, ref))
+ || stmt_may_clobber_ref_p_1 (def_stmt, ref))
&& (*walker) (ref, vdef, data))
return cnt;
}
unsigned int
-walk_aliased_vdefs (tree ref, tree vdef,
- bool (*walker)(tree, tree, void *), void *data,
+walk_aliased_vdefs (ao_ref *ref, tree vdef,
+ bool (*walker)(ao_ref *, tree, void *), void *data,
bitmap *visited)
{
bitmap local_visited = NULL;
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