/* Alias analysis for GNU C
- Copyright (C) 1997, 1998 Free Software Foundation, Inc.
+ Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
Contributed by John Carr (jfc@mit.edu).
This file is part of GNU CC.
#include "config.h"
#include "system.h"
#include "rtl.h"
+#include "tree.h"
+#include "tm_p.h"
+#include "function.h"
+#include "insn-flags.h"
#include "expr.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "flags.h"
-
-static rtx canon_rtx PROTO((rtx));
-static int rtx_equal_for_memref_p PROTO((rtx, rtx));
-static rtx find_symbolic_term PROTO((rtx));
-static int memrefs_conflict_p PROTO((int, rtx, int, rtx,
- HOST_WIDE_INT));
-static void record_set PROTO((rtx, rtx));
-static rtx find_base_term PROTO((rtx));
-static int base_alias_check PROTO((rtx, rtx));
-static int mode_alias_check PROTO((rtx, rtx, int (*)(rtx)));
+#include "output.h"
+#include "toplev.h"
+#include "cselib.h"
+#include "splay-tree.h"
+#include "ggc.h"
+
+/* The alias sets assigned to MEMs assist the back-end in determining
+ which MEMs can alias which other MEMs. In general, two MEMs in
+ different alias sets to not alias each other. There is one
+ exception, however. Consider something like:
+
+ struct S {int i; double d; };
+
+ a store to an `S' can alias something of either type `int' or type
+ `double'. (However, a store to an `int' cannot alias a `double'
+ and vice versa.) We indicate this via a tree structure that looks
+ like:
+ struct S
+ / \
+ / \
+ |/_ _\|
+ int double
+
+ (The arrows are directed and point downwards.) If, when comparing
+ two alias sets, we can hold one set fixed, trace the other set
+ downwards, and at some point find the first set, the two MEMs can
+ alias one another. In this situation we say the alias set for
+ `struct S' is the `superset' and that those for `int' and `double'
+ are `subsets'.
+
+ Alias set zero is implicitly a superset of all other alias sets.
+ However, this is no actual entry for alias set zero. It is an
+ error to attempt to explicitly construct a subset of zero. */
+
+typedef struct alias_set_entry
+{
+ /* The alias set number, as stored in MEM_ALIAS_SET. */
+ int alias_set;
+
+ /* The children of the alias set. These are not just the immediate
+ children, but, in fact, all children. So, if we have:
+
+ struct T { struct S s; float f; }
+
+ continuing our example above, the children here will be all of
+ `int', `double', `float', and `struct S'. */
+ splay_tree children;
+} *alias_set_entry;
+
+static int rtx_equal_for_memref_p PARAMS ((rtx, rtx));
+static rtx find_symbolic_term PARAMS ((rtx));
+static rtx get_addr PARAMS ((rtx));
+static int memrefs_conflict_p PARAMS ((int, rtx, int, rtx,
+ HOST_WIDE_INT));
+static void record_set PARAMS ((rtx, rtx, void *));
+static rtx find_base_term PARAMS ((rtx));
+static int base_alias_check PARAMS ((rtx, rtx, enum machine_mode,
+ enum machine_mode));
+static rtx find_base_value PARAMS ((rtx));
+static int mems_in_disjoint_alias_sets_p PARAMS ((rtx, rtx));
+static int insert_subset_children PARAMS ((splay_tree_node, void*));
+static alias_set_entry get_alias_set_entry PARAMS ((int));
+static rtx fixed_scalar_and_varying_struct_p PARAMS ((rtx, rtx, rtx, rtx,
+ int (*)(rtx)));
+static int aliases_everything_p PARAMS ((rtx));
+static int write_dependence_p PARAMS ((rtx, rtx, int));
+static int nonlocal_reference_p PARAMS ((rtx));
/* Set up all info needed to perform alias analysis on memory references. */
+/* Returns the size in bytes of the mode of X. */
#define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
+/* Returns nonzero if MEM1 and MEM2 do not alias because they are in
+ different alias sets. We ignore alias sets in functions making use
+ of variable arguments because the va_arg macros on some systems are
+ not legal ANSI C. */
+#define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \
+ mems_in_disjoint_alias_sets_p (MEM1, MEM2)
+
/* Cap the number of passes we make over the insns propagating alias
information through set chains.
A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS
expressions represent certain special values: function arguments and
- the stack, frame, and argument pointers. The contents of an address
- expression are not used (but they are descriptive for debugging);
- only the address and mode matter. Pointer equality, not rtx_equal_p,
- determines whether two ADDRESS expressions refer to the same base
- address. The mode determines whether it is a function argument or
- other special value. */
-
-rtx *reg_base_value;
-rtx *new_reg_base_value;
-unsigned int reg_base_value_size; /* size of reg_base_value array */
+ the stack, frame, and argument pointers.
+
+ The contents of an ADDRESS is not normally used, the mode of the
+ ADDRESS determines whether the ADDRESS is a function argument or some
+ other special value. Pointer equality, not rtx_equal_p, determines whether
+ two ADDRESS expressions refer to the same base address.
+
+ The only use of the contents of an ADDRESS is for determining if the
+ current function performs nonlocal memory memory references for the
+ purposes of marking the function as a constant function. */
+
+static rtx *reg_base_value;
+static rtx *new_reg_base_value;
+static unsigned int reg_base_value_size; /* size of reg_base_value array */
+
#define REG_BASE_VALUE(X) \
- (REGNO (X) < reg_base_value_size ? reg_base_value[REGNO (X)] : 0)
+ ((unsigned) REGNO (X) < reg_base_value_size ? reg_base_value[REGNO (X)] : 0)
+
+/* Vector of known invariant relationships between registers. Set in
+ loop unrolling. Indexed by register number, if nonzero the value
+ is an expression describing this register in terms of another.
+
+ The length of this array is REG_BASE_VALUE_SIZE.
+
+ Because this array contains only pseudo registers it has no effect
+ after reload. */
+static rtx *alias_invariant;
-/* Vector indexed by N giving the initial (unchanging) value known
- for pseudo-register N. */
+/* Vector indexed by N giving the initial (unchanging) value known for
+ pseudo-register N. This array is initialized in
+ init_alias_analysis, and does not change until end_alias_analysis
+ is called. */
rtx *reg_known_value;
/* Indicates number of valid entries in reg_known_value. */
-static int reg_known_value_size;
+static unsigned int reg_known_value_size;
/* Vector recording for each reg_known_value whether it is due to a
REG_EQUIV note. Future passes (viz., reload) may replace the
static int copying_arguments;
+/* The splay-tree used to store the various alias set entries. */
+
+static splay_tree alias_sets;
+
+/* Returns a pointer to the alias set entry for ALIAS_SET, if there is
+ such an entry, or NULL otherwise. */
+
+static alias_set_entry
+get_alias_set_entry (alias_set)
+ int alias_set;
+{
+ splay_tree_node sn
+ = splay_tree_lookup (alias_sets, (splay_tree_key) alias_set);
+
+ return sn != 0 ? ((alias_set_entry) sn->value) : 0;
+}
+
+/* Returns nonzero value if the alias sets for MEM1 and MEM2 are such
+ that the two MEMs cannot alias each other. */
+
+static int
+mems_in_disjoint_alias_sets_p (mem1, mem2)
+ rtx mem1;
+ rtx mem2;
+{
+ alias_set_entry ase;
+
+#ifdef ENABLE_CHECKING
+/* Perform a basic sanity check. Namely, that there are no alias sets
+ if we're not using strict aliasing. This helps to catch bugs
+ whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or
+ where a MEM is allocated in some way other than by the use of
+ gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to
+ use alias sets to indicate that spilled registers cannot alias each
+ other, we might need to remove this check. */
+ if (! flag_strict_aliasing
+ && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0))
+ abort ();
+#endif
+
+ /* The code used in varargs macros are often not conforming ANSI C,
+ which can trick the compiler into making incorrect aliasing
+ assumptions in these functions. So, we don't use alias sets in
+ such a function. FIXME: This should be moved into the front-end;
+ it is a language-dependent notion, and there's no reason not to
+ still use these checks to handle globals. */
+ if (current_function_stdarg || current_function_varargs)
+ return 0;
+
+ /* If have no alias set information for one of the MEMs, we have to assume
+ it can alias anything. */
+ if (MEM_ALIAS_SET (mem1) == 0 || MEM_ALIAS_SET (mem2) == 0)
+ return 0;
+
+ /* If the two alias sets are the same, they may alias. */
+ if (MEM_ALIAS_SET (mem1) == MEM_ALIAS_SET (mem2))
+ return 0;
+
+ /* Iterate through each of the children of the first alias set,
+ comparing it with the second alias set. */
+ ase = get_alias_set_entry (MEM_ALIAS_SET (mem1));
+ if (ase != 0 && splay_tree_lookup (ase->children,
+ (splay_tree_key) MEM_ALIAS_SET (mem2)))
+ return 0;
+
+ /* Now do the same, but with the alias sets reversed. */
+ ase = get_alias_set_entry (MEM_ALIAS_SET (mem2));
+ if (ase != 0 && splay_tree_lookup (ase->children,
+ (splay_tree_key) MEM_ALIAS_SET (mem1)))
+ return 0;
+
+ /* The two MEMs are in distinct alias sets, and neither one is the
+ child of the other. Therefore, they cannot alias. */
+ return 1;
+}
+
+/* Insert the NODE into the splay tree given by DATA. Used by
+ record_alias_subset via splay_tree_foreach. */
+
+static int
+insert_subset_children (node, data)
+ splay_tree_node node;
+ void *data;
+{
+ splay_tree_insert ((splay_tree) data, node->key, node->value);
+
+ return 0;
+}
+
+/* Indicate that things in SUBSET can alias things in SUPERSET, but
+ not vice versa. For example, in C, a store to an `int' can alias a
+ structure containing an `int', but not vice versa. Here, the
+ structure would be the SUPERSET and `int' the SUBSET. This
+ function should be called only once per SUPERSET/SUBSET pair. At
+ present any given alias set may only be a subset of one superset.
+
+ It is illegal for SUPERSET to be zero; everything is implicitly a
+ subset of alias set zero. */
+
+void
+record_alias_subset (superset, subset)
+ int superset;
+ int subset;
+{
+ alias_set_entry superset_entry;
+ alias_set_entry subset_entry;
+
+ if (superset == 0)
+ abort ();
+
+ superset_entry = get_alias_set_entry (superset);
+ if (superset_entry == 0)
+ {
+ /* Create an entry for the SUPERSET, so that we have a place to
+ attach the SUBSET. */
+ superset_entry
+ = (alias_set_entry) xmalloc (sizeof (struct alias_set_entry));
+ superset_entry->alias_set = superset;
+ superset_entry->children
+ = splay_tree_new (splay_tree_compare_ints, 0, 0);
+ splay_tree_insert (alias_sets, (splay_tree_key) superset,
+ (splay_tree_value) superset_entry);
+
+ }
+
+ subset_entry = get_alias_set_entry (subset);
+
+ /* If there is an entry for the subset, enter all of its children
+ (if they are not already present) as children of the SUPERSET. */
+ if (subset_entry)
+ splay_tree_foreach (subset_entry->children,
+ insert_subset_children,
+ superset_entry->children);
+
+ /* Enter the SUBSET itself as a child of the SUPERSET. */
+ splay_tree_insert (superset_entry->children,
+ (splay_tree_key) subset, 0);
+}
+
/* Inside SRC, the source of a SET, find a base address. */
static rtx
return src;
case REG:
- /* At the start of a function argument registers have known base
+ /* At the start of a function, argument registers have known base
values which may be lost later. Returning an ADDRESS
expression here allows optimization based on argument values
even when the argument registers are used for other purposes. */
The test above is not sufficient because the scheduler may move
a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */
if (REGNO (src) >= FIRST_PSEUDO_REGISTER
+ && (unsigned) REGNO (src) < reg_base_value_size
&& reg_base_value[REGNO (src)])
return reg_base_value[REGNO (src)];
src = XEXP (src, 0);
if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
break;
- /* fall through */
+
+ /* ... fall through ... */
case PLUS:
case MINUS:
if (GET_CODE (src_0) == REG)
{
temp = find_base_value (src_0);
- if (temp)
+ if (temp != 0)
src_0 = temp;
}
if (GET_CODE (src_1) == REG)
{
temp = find_base_value (src_1);
- if (temp)
+ if (temp!= 0)
src_1 = temp;
}
- /* Guess which operand is the base address.
-
+ /* Guess which operand is the base address:
If either operand is a symbol, then it is the base. If
either operand is a CONST_INT, then the other is the base. */
-
- if (GET_CODE (src_1) == CONST_INT
- || GET_CODE (src_0) == SYMBOL_REF
- || GET_CODE (src_0) == LABEL_REF
- || GET_CODE (src_0) == CONST)
+ if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0))
return find_base_value (src_0);
-
- if (GET_CODE (src_0) == CONST_INT
- || GET_CODE (src_1) == SYMBOL_REF
- || GET_CODE (src_1) == LABEL_REF
- || GET_CODE (src_1) == CONST)
+ else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1))
return find_base_value (src_1);
- /* This might not be necessary anymore.
-
+ /* This might not be necessary anymore:
If either operand is a REG that is a known pointer, then it
is the base. */
- if (GET_CODE (src_0) == REG && REGNO_POINTER_FLAG (REGNO (src_0)))
+ else if (GET_CODE (src_0) == REG && REGNO_POINTER_FLAG (REGNO (src_0)))
return find_base_value (src_0);
-
- if (GET_CODE (src_1) == REG && REGNO_POINTER_FLAG (REGNO (src_1)))
+ else if (GET_CODE (src_1) == REG && REGNO_POINTER_FLAG (REGNO (src_1)))
return find_base_value (src_1);
return 0;
return find_base_value (XEXP (src, 0));
return 0;
+ case ZERO_EXTEND:
+ case SIGN_EXTEND: /* used for NT/Alpha pointers */
case HIGH:
return find_base_value (XEXP (src, 0));
/* Called from init_alias_analysis indirectly through note_stores. */
-/* while scanning insns to find base values, reg_seen[N] is nonzero if
+/* While scanning insns to find base values, reg_seen[N] is nonzero if
register N has been set in this function. */
static char *reg_seen;
static int unique_id;
static void
-record_set (dest, set)
+record_set (dest, set, data)
rtx dest, set;
+ void *data ATTRIBUTE_UNUSED;
{
- register int regno;
+ register unsigned regno;
rtx src;
if (GET_CODE (dest) != REG)
regno = REGNO (dest);
+ if (regno >= reg_base_value_size)
+ abort ();
+
if (set)
{
/* A CLOBBER wipes out any old value but does not prevent a previously
}
/* Called from loop optimization when a new pseudo-register is created. */
+
void
-record_base_value (regno, val)
+record_base_value (regno, val, invariant)
int regno;
rtx val;
+ int invariant;
{
- if (regno >= reg_base_value_size)
+ if ((unsigned) regno >= reg_base_value_size)
return;
+
+ /* If INVARIANT is true then this value also describes an invariant
+ relationship which can be used to deduce that two registers with
+ unknown values are different. */
+ if (invariant && alias_invariant)
+ alias_invariant[regno] = val;
+
if (GET_CODE (val) == REG)
{
- if (REGNO (val) < reg_base_value_size)
+ if ((unsigned) REGNO (val) < reg_base_value_size)
reg_base_value[regno] = reg_base_value[REGNO (val)];
+
return;
}
+
reg_base_value[regno] = find_base_value (val);
}
-static rtx
+/* Returns a canonical version of X, from the point of view alias
+ analysis. (For example, if X is a MEM whose address is a register,
+ and the register has a known value (say a SYMBOL_REF), then a MEM
+ whose address is the SYMBOL_REF is returned.) */
+
+rtx
canon_rtx (x)
rtx x;
{
return gen_rtx_PLUS (GET_MODE (x), x0, x1);
}
}
+
/* This gives us much better alias analysis when called from
the loop optimizer. Note we want to leave the original
MEM alone, but need to return the canonicalized MEM with
else if (GET_CODE (x) == MEM)
{
rtx addr = canon_rtx (XEXP (x, 0));
+
if (addr != XEXP (x, 0))
{
rtx new = gen_rtx_MEM (GET_MODE (x), addr);
- MEM_VOLATILE_P (new) = MEM_VOLATILE_P (x);
+
RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (x);
- MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (x);
+ MEM_COPY_ATTRIBUTES (new, x);
+ MEM_ALIAS_SET (new) = MEM_ALIAS_SET (x);
x = new;
}
}
register int i;
register int j;
register enum rtx_code code;
- register char *fmt;
+ register const char *fmt;
if (x == 0 && y == 0)
return 1;
if (x == 0 || y == 0)
return 0;
+
x = canon_rtx (x);
y = canon_rtx (y);
if (GET_MODE (x) != GET_MODE (y))
return 0;
- /* REG, LABEL_REF, and SYMBOL_REF can be compared nonrecursively. */
+ /* Some RTL can be compared without a recursive examination. */
+ switch (code)
+ {
+ case REG:
+ return REGNO (x) == REGNO (y);
- if (code == REG)
- return REGNO (x) == REGNO (y);
- if (code == LABEL_REF)
- return XEXP (x, 0) == XEXP (y, 0);
- if (code == SYMBOL_REF)
- return XSTR (x, 0) == XSTR (y, 0);
+ case LABEL_REF:
+ return XEXP (x, 0) == XEXP (y, 0);
+
+ case SYMBOL_REF:
+ return XSTR (x, 0) == XSTR (y, 0);
+
+ case CONST_INT:
+ case CONST_DOUBLE:
+ /* There's no need to compare the contents of CONST_DOUBLEs or
+ CONST_INTs because pointer equality is a good enough
+ comparison for these nodes. */
+ return 0;
+
+ case ADDRESSOF:
+ return (REGNO (XEXP (x, 0)) == REGNO (XEXP (y, 0))
+ && XINT (x, 1) == XINT (y, 1));
+
+ default:
+ break;
+ }
/* For commutative operations, the RTX match if the operand match in any
order. Also handle the simple binary and unary cases without a loop. */
return rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0));
/* Compare the elements. If any pair of corresponding elements
- fail to match, return 0 for the whole things. */
+ fail to match, return 0 for the whole things.
+
+ Limit cases to types which actually appear in addresses. */
fmt = GET_RTX_FORMAT (code);
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
switch (fmt[i])
{
- case 'w':
- if (XWINT (x, i) != XWINT (y, i))
- return 0;
- break;
-
- case 'n':
case 'i':
if (XINT (x, i) != XINT (y, i))
return 0;
break;
- case 'V':
case 'E':
/* Two vectors must have the same length. */
if (XVECLEN (x, i) != XVECLEN (y, i))
/* And the corresponding elements must match. */
for (j = 0; j < XVECLEN (x, i); j++)
- if (rtx_equal_for_memref_p (XVECEXP (x, i, j), XVECEXP (y, i, j)) == 0)
+ if (rtx_equal_for_memref_p (XVECEXP (x, i, j),
+ XVECEXP (y, i, j)) == 0)
return 0;
break;
return 0;
break;
- case 'S':
- case 's':
- if (strcmp (XSTR (x, i), XSTR (y, i)))
- return 0;
- break;
-
- case 'u':
- /* These are just backpointers, so they don't matter. */
- break;
-
+ /* This can happen for an asm which clobbers memory. */
case '0':
break;
{
register int i;
register enum rtx_code code;
- register char *fmt;
+ register const char *fmt;
code = GET_CODE (x);
if (code == SYMBOL_REF || code == LABEL_REF)
find_base_term (x)
register rtx x;
{
+ cselib_val *val;
+ struct elt_loc_list *l;
+
switch (GET_CODE (x))
{
case REG:
return REG_BASE_VALUE (x);
+ case ZERO_EXTEND:
+ case SIGN_EXTEND: /* Used for Alpha/NT pointers */
case HIGH:
- return find_base_term (XEXP (x, 0));
-
case PRE_INC:
case PRE_DEC:
case POST_INC:
case POST_DEC:
return find_base_term (XEXP (x, 0));
+ case VALUE:
+ val = CSELIB_VAL_PTR (x);
+ for (l = val->locs; l; l = l->next)
+ if ((x = find_base_term (l->loc)) != 0)
+ return x;
+ return 0;
+
case CONST:
x = XEXP (x, 0);
if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS)
case PLUS:
case MINUS:
{
- rtx tmp = find_base_term (XEXP (x, 0));
- if (tmp)
- return tmp;
- return find_base_term (XEXP (x, 1));
+ rtx tmp1 = XEXP (x, 0);
+ rtx tmp2 = XEXP (x, 1);
+
+ /* This is a litle bit tricky since we have to determine which of
+ the two operands represents the real base address. Otherwise this
+ routine may return the index register instead of the base register.
+
+ That may cause us to believe no aliasing was possible, when in
+ fact aliasing is possible.
+
+ We use a few simple tests to guess the base register. Additional
+ tests can certainly be added. For example, if one of the operands
+ is a shift or multiply, then it must be the index register and the
+ other operand is the base register. */
+
+ /* If either operand is known to be a pointer, then use it
+ to determine the base term. */
+ if (REG_P (tmp1) && REGNO_POINTER_FLAG (REGNO (tmp1)))
+ return find_base_term (tmp1);
+
+ if (REG_P (tmp2) && REGNO_POINTER_FLAG (REGNO (tmp2)))
+ return find_base_term (tmp2);
+
+ /* Neither operand was known to be a pointer. Go ahead and find the
+ base term for both operands. */
+ tmp1 = find_base_term (tmp1);
+ tmp2 = find_base_term (tmp2);
+
+ /* If either base term is named object or a special address
+ (like an argument or stack reference), then use it for the
+ base term. */
+ if (tmp1 != 0
+ && (GET_CODE (tmp1) == SYMBOL_REF
+ || GET_CODE (tmp1) == LABEL_REF
+ || (GET_CODE (tmp1) == ADDRESS
+ && GET_MODE (tmp1) != VOIDmode)))
+ return tmp1;
+
+ if (tmp2 != 0
+ && (GET_CODE (tmp2) == SYMBOL_REF
+ || GET_CODE (tmp2) == LABEL_REF
+ || (GET_CODE (tmp2) == ADDRESS
+ && GET_MODE (tmp2) != VOIDmode)))
+ return tmp2;
+
+ /* We could not determine which of the two operands was the
+ base register and which was the index. So we can determine
+ nothing from the base alias check. */
+ return 0;
}
case AND:
objects, 1 if they might be pointers to the same object. */
static int
-base_alias_check (x, y)
+base_alias_check (x, y, x_mode, y_mode)
rtx x, y;
+ enum machine_mode x_mode, y_mode;
{
rtx x_base = find_base_term (x);
rtx y_base = find_base_term (y);
if (x_base == 0)
{
rtx x_c;
+
if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x)
return 1;
+
x_base = find_base_term (x_c);
if (x_base == 0)
return 1;
rtx y_c;
if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y)
return 1;
+
y_base = find_base_term (y_c);
if (y_base == 0)
return 1;
if (rtx_equal_p (x_base, y_base))
return 1;
- /* The base addresses of the read and write are different
- expressions. If they are both symbols and they are not accessed
- via AND, there is no conflict. */
- /* XXX: We can bring knowledge of object alignment and offset into
- play here. For example, on alpha, "char a, b;" can alias one
- another, though "char a; long b;" cannot. Similarly, offsets
- into strutures may be brought into play. Given "char a, b[40];",
- a and b[1] may overlap, but a and b[20] do not. */
+ /* The base addresses of the read and write are different expressions.
+ If they are both symbols and they are not accessed via AND, there is
+ no conflict. We can bring knowledge of object alignment into play
+ here. For example, on alpha, "char a, b;" can alias one another,
+ though "char a; long b;" cannot. */
if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS)
{
- return GET_CODE (x) == AND || GET_CODE (y) == AND;
+ if (GET_CODE (x) == AND && GET_CODE (y) == AND)
+ return 1;
+ if (GET_CODE (x) == AND
+ && (GET_CODE (XEXP (x, 1)) != CONST_INT
+ || GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
+ return 1;
+ if (GET_CODE (y) == AND
+ && (GET_CODE (XEXP (y, 1)) != CONST_INT
+ || GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
+ return 1;
+ /* Differing symbols never alias. */
+ return 0;
}
/* If one address is a stack reference there can be no alias:
return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode);
}
+/* Convert the address X into something we can use. This is done by returning
+ it unchanged unless it is a value; in the latter case we call cselib to get
+ a more useful rtx. */
+static rtx
+get_addr (x)
+ rtx x;
+{
+ cselib_val *v;
+ struct elt_loc_list *l;
+
+ if (GET_CODE (x) != VALUE)
+ return x;
+ v = CSELIB_VAL_PTR (x);
+ for (l = v->locs; l; l = l->next)
+ if (CONSTANT_P (l->loc))
+ return l->loc;
+ for (l = v->locs; l; l = l->next)
+ if (GET_CODE (l->loc) != REG && GET_CODE (l->loc) != MEM)
+ return l->loc;
+ if (v->locs)
+ return v->locs->loc;
+ return x;
+}
+
+/* Return the address of the (N_REFS + 1)th memory reference to ADDR
+ where SIZE is the size in bytes of the memory reference. If ADDR
+ is not modified by the memory reference then ADDR is returned. */
+
+rtx
+addr_side_effect_eval (addr, size, n_refs)
+ rtx addr;
+ int size;
+ int n_refs;
+{
+ int offset = 0;
+
+ switch (GET_CODE (addr))
+ {
+ case PRE_INC:
+ offset = (n_refs + 1) * size;
+ break;
+ case PRE_DEC:
+ offset = -(n_refs + 1) * size;
+ break;
+ case POST_INC:
+ offset = n_refs * size;
+ break;
+ case POST_DEC:
+ offset = -n_refs * size;
+ break;
+
+ default:
+ return addr;
+ }
+
+ if (offset)
+ addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset));
+ else
+ addr = XEXP (addr, 0);
+
+ return addr;
+}
+
/* Return nonzero if X and Y (memory addresses) could reference the
same location in memory. C is an offset accumulator. When
C is nonzero, we are testing aliases between X and Y + C.
align memory references, as is done on the Alpha.
Nice to notice that varying addresses cannot conflict with fp if no
- local variables had their addresses taken, but that's too hard now.
-
- TODO: (symbol_ref foo) can not alias (plus REG N) if N is a positive
- integer because REG would have to point outside of the object, which
- is not allowed in C or C++. */
-
+ local variables had their addresses taken, but that's too hard now. */
static int
memrefs_conflict_p (xsize, x, ysize, y, c)
int xsize, ysize;
HOST_WIDE_INT c;
{
+ if (GET_CODE (x) == VALUE)
+ x = get_addr (x);
+ if (GET_CODE (y) == VALUE)
+ y = get_addr (y);
if (GET_CODE (x) == HIGH)
x = XEXP (x, 0);
else if (GET_CODE (x) == LO_SUM)
x = XEXP (x, 1);
else
- x = canon_rtx (x);
+ x = canon_rtx (addr_side_effect_eval (x, xsize, 0));
if (GET_CODE (y) == HIGH)
y = XEXP (y, 0);
else if (GET_CODE (y) == LO_SUM)
y = XEXP (y, 1);
else
- y = canon_rtx (y);
+ y = canon_rtx (addr_side_effect_eval (y, ysize, 0));
if (rtx_equal_for_memref_p (x, y))
{
if (rtx_equal_for_memref_p (x0, y0))
return memrefs_conflict_p (xsize, x1, ysize, y1, c);
if (GET_CODE (x1) == CONST_INT)
- if (GET_CODE (y1) == CONST_INT)
- return memrefs_conflict_p (xsize, x0, ysize, y0,
- c - INTVAL (x1) + INTVAL (y1));
- else
- return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1));
+ {
+ if (GET_CODE (y1) == CONST_INT)
+ return memrefs_conflict_p (xsize, x0, ysize, y0,
+ c - INTVAL (x1) + INTVAL (y1));
+ else
+ return memrefs_conflict_p (xsize, x0, ysize, y,
+ c - INTVAL (x1));
+ }
else if (GET_CODE (y1) == CONST_INT)
return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
return memrefs_conflict_p (xsize, x0, ysize, y0, c);
}
+ case REG:
+ /* Are these registers known not to be equal? */
+ if (alias_invariant)
+ {
+ unsigned int r_x = REGNO (x), r_y = REGNO (y);
+ rtx i_x, i_y; /* invariant relationships of X and Y */
+
+ i_x = r_x >= reg_base_value_size ? 0 : alias_invariant[r_x];
+ i_y = r_y >= reg_base_value_size ? 0 : alias_invariant[r_y];
+
+ if (i_x == 0 && i_y == 0)
+ break;
+
+ if (! memrefs_conflict_p (xsize, i_x ? i_x : x,
+ ysize, i_y ? i_y : y, c))
+ return 0;
+ }
+ break;
+
default:
break;
}
/* Treat an access through an AND (e.g. a subword access on an Alpha)
- as an access with indeterminate size.
- ??? Could instead convert an n byte reference at (and x y) to an
- n-y byte reference at (plus x y). */
+ as an access with indeterminate size. Assume that references
+ besides AND are aligned, so if the size of the other reference is
+ at least as large as the alignment, assume no other overlap. */
if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT)
- return memrefs_conflict_p (-1, XEXP (x, 0), ysize, y, c);
+ {
+ if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
+ xsize = -1;
+ return memrefs_conflict_p (xsize, XEXP (x, 0), ysize, y, c);
+ }
if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT)
{
- /* XXX: If we are indexing far enough into the array/structure, we
+ /* ??? If we are indexing far enough into the array/structure, we
may yet be able to determine that we can not overlap. But we
also need to that we are far enough from the end not to overlap
- a following reference, so we do nothing for now. */
- return memrefs_conflict_p (xsize, x, -1, XEXP (y, 0), c);
+ a following reference, so we do nothing with that for now. */
+ if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1)))
+ ysize = -1;
+ return memrefs_conflict_p (xsize, x, ysize, XEXP (y, 0), c);
}
if (CONSTANT_P (x))
generate aligned addresses from unaligned addresses, for instance, the
alpha storeqi_unaligned pattern. */
-
-/* This subroutine implements the type and struct/varying part of the
- alias check.
-
- Return 0 if the memory references can never alias.
- Return 1 if the values of the addresses should be checked. */
-
-static int
-mode_alias_check (x, y, varies)
- register rtx x, y;
- int (*varies) PROTO ((rtx));
-{
- enum machine_mode x_mode = GET_MODE (x), y_mode = GET_MODE (y);
- rtx x_addr = XEXP (x, 0), y_addr = XEXP (y, 0);
- int x_varies, y_varies, x_struct, y_struct;
-
- /* If either address is an AND then neither the mode check nor the
- struct/varying check is valid. */
- if (GET_CODE (x_addr) == AND || GET_CODE (y_addr) == AND)
- return 1;
-
- x_struct = MEM_IN_STRUCT_P (x);
- y_struct = MEM_IN_STRUCT_P (y);
-
- /* QImode and BLKmode references can alias anything. */
- if (x_mode == QImode || x_mode == BLKmode
- || y_mode == QImode || y_mode == BLKmode)
- return 1;
-
- /* Otherwise, different modes can only alias if they are structure
- references. gcc bitfield operations can access an entire word,
- but that word may also contain integers accessed directly.
-
- ??? It appears that bitfield accesses can not be larger than
- word_mode?
- ??? Can complex modes alias their components? */
- if (x_mode != y_mode && ! (x_struct && y_struct))
- return 0;
-
- /* Modes are the same or may alias. */
-
- /* No alias if one reference is a struct at a varying address and the
- other is a scalar at a fixed address.
-
- If either reference is a varying scalar or a fixed struct nothing
- is known about aliasing. */
- x_varies = varies (x_addr);
- if (x_struct != x_varies)
- return 1;
- y_varies = varies (y_addr);
- if (y_struct != y_varies)
- return 1;
-
- /* Both are varying structs or fixed scalars. Check that they are not
- the same type. */
- return (x_struct == y_struct);
-}
-
/* Read dependence: X is read after read in MEM takes place. There can
only be a dependence here if both reads are volatile. */
return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem);
}
+/* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and
+ MEM2 is a reference to a structure at a varying address, or returns
+ MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL
+ value is returned MEM1 and MEM2 can never alias. VARIES_P is used
+ to decide whether or not an address may vary; it should return
+ nonzero whenever variation is possible.
+ MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */
+
+static rtx
+fixed_scalar_and_varying_struct_p (mem1, mem2, mem1_addr, mem2_addr, varies_p)
+ rtx mem1, mem2;
+ rtx mem1_addr, mem2_addr;
+ int (*varies_p) PARAMS ((rtx));
+{
+ if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2)
+ && !varies_p (mem1_addr) && varies_p (mem2_addr))
+ /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a
+ varying address. */
+ return mem1;
+
+ if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2)
+ && varies_p (mem1_addr) && !varies_p (mem2_addr))
+ /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a
+ varying address. */
+ return mem2;
+
+ return NULL_RTX;
+}
+
+/* Returns nonzero if something about the mode or address format MEM1
+ indicates that it might well alias *anything*. */
+
+static int
+aliases_everything_p (mem)
+ rtx mem;
+{
+ if (GET_MODE (mem) == QImode)
+ /* ANSI C says that a `char*' can point to anything. */
+ return 1;
+
+ if (GET_CODE (XEXP (mem, 0)) == AND)
+ /* If the address is an AND, its very hard to know at what it is
+ actually pointing. */
+ return 1;
+
+ return 0;
+}
+
/* True dependence: X is read after store in MEM takes place. */
int
rtx mem;
enum machine_mode mem_mode;
rtx x;
- int (*varies)();
+ int (*varies) PARAMS ((rtx));
{
register rtx x_addr, mem_addr;
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
return 1;
+ if (DIFFERENT_ALIAS_SETS_P (x, mem))
+ return 0;
+
/* If X is an unchanging read, then it can't possibly conflict with any
non-unchanging store. It may conflict with an unchanging write though,
because there may be a single store to this address to initialize it.
if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem))
return 0;
- if (! base_alias_check (XEXP (x, 0), XEXP (mem, 0)))
+ if (mem_mode == VOIDmode)
+ mem_mode = GET_MODE (mem);
+
+ x_addr = get_addr (XEXP (x, 0));
+ mem_addr = get_addr (XEXP (mem, 0));
+
+ if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
return 0;
- if (! mode_alias_check (x, mem, varies))
+ x_addr = canon_rtx (x_addr);
+ mem_addr = canon_rtx (mem_addr);
+
+ if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
+ SIZE_FOR_MODE (x), x_addr, 0))
return 0;
- x_addr = canon_rtx (XEXP (x, 0));
- mem_addr = canon_rtx (XEXP (mem, 0));
+ if (aliases_everything_p (x))
+ return 1;
- if (mem_mode == VOIDmode)
- mem_mode = GET_MODE (mem);
+ /* We cannot use aliases_everyting_p to test MEM, since we must look
+ at MEM_MODE, rather than GET_MODE (MEM). */
+ if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
+ return 1;
- return memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
- SIZE_FOR_MODE (x), x_addr, 0);
+ /* In true_dependence we also allow BLKmode to alias anything. Why
+ don't we do this in anti_dependence and output_dependence? */
+ if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
+ return 1;
+
+ return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
+ varies);
}
-/* Anti dependence: X is written after read in MEM takes place. */
+/* Returns non-zero if a write to X might alias a previous read from
+ (or, if WRITEP is non-zero, a write to) MEM. */
-int
-anti_dependence (mem, x)
+static int
+write_dependence_p (mem, x, writep)
rtx mem;
rtx x;
+ int writep;
{
rtx x_addr, mem_addr;
+ rtx fixed_scalar;
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
return 1;
+ if (DIFFERENT_ALIAS_SETS_P (x, mem))
+ return 0;
+
/* If MEM is an unchanging read, then it can't possibly conflict with
the store to X, because there is at most one store to MEM, and it must
have occurred somewhere before MEM. */
- if (RTX_UNCHANGING_P (mem))
+ if (!writep && RTX_UNCHANGING_P (mem))
return 0;
- if (! base_alias_check (XEXP (x, 0), XEXP (mem, 0)))
- return 0;
+ x_addr = get_addr (XEXP (x, 0));
+ mem_addr = get_addr (XEXP (mem, 0));
- x = canon_rtx (x);
- mem = canon_rtx (mem);
+ if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
+ GET_MODE (mem)))
+ return 0;
- x_addr = XEXP (x, 0);
- mem_addr = XEXP (mem, 0);
+ x_addr = canon_rtx (x_addr);
+ mem_addr = canon_rtx (mem_addr);
- if (! mode_alias_check (x, mem, rtx_varies_p))
+ if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
+ SIZE_FOR_MODE (x), x_addr, 0))
return 0;
- return memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
- SIZE_FOR_MODE (x), x_addr, 0);
+ fixed_scalar
+ = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
+ rtx_addr_varies_p);
+
+ return (!(fixed_scalar == mem && !aliases_everything_p (x))
+ && !(fixed_scalar == x && !aliases_everything_p (mem)));
+}
+
+/* Anti dependence: X is written after read in MEM takes place. */
+
+int
+anti_dependence (mem, x)
+ rtx mem;
+ rtx x;
+{
+ return write_dependence_p (mem, x, /*writep=*/0);
}
/* Output dependence: X is written after store in MEM takes place. */
register rtx mem;
register rtx x;
{
- if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
- return 1;
+ return write_dependence_p (mem, x, /*writep=*/1);
+}
- if (! base_alias_check (XEXP (x, 0), XEXP (mem, 0)))
- return 0;
+/* Returns non-zero if X might refer to something which is not
+ local to the function and is not constant. */
- x = canon_rtx (x);
- mem = canon_rtx (mem);
+static int
+nonlocal_reference_p (x)
+ rtx x;
+{
+ rtx base;
+ register RTX_CODE code;
+ int regno;
- if (! mode_alias_check (x, mem, rtx_varies_p))
- return 0;
+ code = GET_CODE (x);
+
+ if (GET_RTX_CLASS (code) == 'i')
+ {
+ /* Constant functions are constant. */
+ if (code == CALL_INSN && CONST_CALL_P (x))
+ return 0;
+ x = PATTERN (x);
+ code = GET_CODE (x);
+ }
+
+ switch (code)
+ {
+ case SUBREG:
+ if (GET_CODE (SUBREG_REG (x)) == REG)
+ {
+ /* Global registers are not local. */
+ if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER
+ && global_regs[REGNO (SUBREG_REG (x)) + SUBREG_WORD (x)])
+ return 1;
+ return 0;
+ }
+ break;
+
+ case REG:
+ regno = REGNO (x);
+ /* Global registers are not local. */
+ if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
+ return 1;
+ return 0;
+
+ case SCRATCH:
+ case PC:
+ case CC0:
+ case CONST_INT:
+ case CONST_DOUBLE:
+ case CONST:
+ case LABEL_REF:
+ return 0;
+
+ case SYMBOL_REF:
+ /* Constants in the function's constants pool are constant. */
+ if (CONSTANT_POOL_ADDRESS_P (x))
+ return 0;
+ return 1;
+
+ case CALL:
+ /* Recursion introduces no additional considerations. */
+ if (GET_CODE (XEXP (x, 0)) == MEM
+ && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
+ && strcmp(XSTR (XEXP (XEXP (x, 0), 0), 0),
+ IDENTIFIER_POINTER (
+ DECL_ASSEMBLER_NAME (current_function_decl))) == 0)
+ return 0;
+ return 1;
+
+ case MEM:
+ /* Be overly conservative and consider any volatile memory
+ reference as not local. */
+ if (MEM_VOLATILE_P (x))
+ return 1;
+ base = find_base_term (XEXP (x, 0));
+ if (base)
+ {
+ /* A Pmode ADDRESS could be a reference via the structure value
+ address or static chain. Such memory references are nonlocal.
+
+ Thus, we have to examine the contents of the ADDRESS to find
+ out if this is a local reference or not. */
+ if (GET_CODE (base) == ADDRESS
+ && GET_MODE (base) == Pmode
+ && (XEXP (base, 0) == stack_pointer_rtx
+ || XEXP (base, 0) == arg_pointer_rtx
+#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
+ || XEXP (base, 0) == hard_frame_pointer_rtx
+#endif
+ || XEXP (base, 0) == frame_pointer_rtx))
+ return 0;
+ /* Constants in the function's constant pool are constant. */
+ if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base))
+ return 0;
+ }
+ return 1;
+
+ case ASM_INPUT:
+ case ASM_OPERANDS:
+ return 1;
+
+ default:
+ break;
+ }
- return memrefs_conflict_p (SIZE_FOR_MODE (mem), XEXP (mem, 0),
- SIZE_FOR_MODE (x), XEXP (x, 0), 0);
+ /* Recursively scan the operands of this expression. */
+
+ {
+ register const char *fmt = GET_RTX_FORMAT (code);
+ register int i;
+
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ if (fmt[i] == 'e')
+ {
+ if (nonlocal_reference_p (XEXP (x, i)))
+ return 1;
+ }
+ else if (fmt[i] == 'E')
+ {
+ register int j;
+ for (j = 0; j < XVECLEN (x, i); j++)
+ if (nonlocal_reference_p (XVECEXP (x, i, j)))
+ return 1;
+ }
+ }
+ }
+
+ return 0;
+}
+
+/* Mark the function if it is constant. */
+
+void
+mark_constant_function ()
+{
+ rtx insn;
+
+ if (TREE_PUBLIC (current_function_decl)
+ || TREE_READONLY (current_function_decl)
+ || TREE_THIS_VOLATILE (current_function_decl)
+ || TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode)
+ return;
+
+ /* Determine if this is a constant function. */
+
+ for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+ if (GET_RTX_CLASS (GET_CODE (insn)) == 'i'
+ && nonlocal_reference_p (insn))
+ return;
+
+ /* Mark the function. */
+
+ TREE_READONLY (current_function_decl) = 1;
}
if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i))
&& HARD_REGNO_MODE_OK (i, Pmode))
SET_HARD_REG_BIT (argument_registers, i);
+
+ alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0);
}
+/* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE
+ array. */
+
void
init_alias_analysis ()
{
int maxreg = max_reg_num ();
int changed, pass;
register int i;
+ register unsigned int ui;
register rtx insn;
reg_known_value_size = maxreg;
- reg_known_value
- = (rtx *) oballoc ((maxreg - FIRST_PSEUDO_REGISTER) * sizeof (rtx))
+ reg_known_value
+ = (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx))
+ - FIRST_PSEUDO_REGISTER;
+ reg_known_equiv_p
+ = (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char))
- FIRST_PSEUDO_REGISTER;
- reg_known_equiv_p =
- oballoc (maxreg - FIRST_PSEUDO_REGISTER) - FIRST_PSEUDO_REGISTER;
- bzero ((char *) (reg_known_value + FIRST_PSEUDO_REGISTER),
- (maxreg-FIRST_PSEUDO_REGISTER) * sizeof (rtx));
- bzero (reg_known_equiv_p + FIRST_PSEUDO_REGISTER,
- (maxreg - FIRST_PSEUDO_REGISTER) * sizeof (char));
/* Overallocate reg_base_value to allow some growth during loop
optimization. Loop unrolling can create a large number of
registers. */
reg_base_value_size = maxreg * 2;
- reg_base_value = (rtx *)oballoc (reg_base_value_size * sizeof (rtx));
- new_reg_base_value = (rtx *)alloca (reg_base_value_size * sizeof (rtx));
- reg_seen = (char *)alloca (reg_base_value_size);
- bzero ((char *) reg_base_value, reg_base_value_size * sizeof (rtx));
+ reg_base_value = (rtx *) xcalloc (reg_base_value_size, sizeof (rtx));
+ if (ggc_p)
+ ggc_add_rtx_root (reg_base_value, reg_base_value_size);
+
+ new_reg_base_value = (rtx *) xmalloc (reg_base_value_size * sizeof (rtx));
+ reg_seen = (char *) xmalloc (reg_base_value_size);
+ if (! reload_completed && flag_unroll_loops)
+ {
+ /* ??? Why are we realloc'ing if we're just going to zero it? */
+ alias_invariant = (rtx *)xrealloc (alias_invariant,
+ reg_base_value_size * sizeof (rtx));
+ bzero ((char *)alias_invariant, reg_base_value_size * sizeof (rtx));
+ }
+
/* The basic idea is that each pass through this loop will use the
"constant" information from the previous pass to propagate alias
/* Walk the insns adding values to the new_reg_base_value array. */
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
{
+#if defined (HAVE_prologue) || defined (HAVE_epilogue)
+ if (prologue_epilogue_contains (insn))
+ continue;
+#endif
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
{
rtx note, set;
if (GET_CODE (PATTERN (insn)) == SET
&& (find_reg_note (insn, REG_NOALIAS, NULL_RTX)))
- record_set (SET_DEST (PATTERN (insn)), NULL_RTX);
+ record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL);
else
- note_stores (PATTERN (insn), record_set);
+ note_stores (PATTERN (insn), record_set, NULL);
set = single_set (insn);
&& (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0
&& REG_N_SETS (REGNO (SET_DEST (set))) == 1)
|| (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0)
- && GET_CODE (XEXP (note, 0)) != EXPR_LIST)
+ && GET_CODE (XEXP (note, 0)) != EXPR_LIST
+ && ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0)))
{
int regno = REGNO (SET_DEST (set));
reg_known_value[regno] = XEXP (note, 0);
}
/* Now propagate values from new_reg_base_value to reg_base_value. */
- for (i = 0; i < reg_base_value_size; i++)
+ for (ui = 0; ui < reg_base_value_size; ui++)
{
- if (new_reg_base_value[i]
- && new_reg_base_value[i] != reg_base_value[i]
- && ! rtx_equal_p (new_reg_base_value[i], reg_base_value[i]))
+ if (new_reg_base_value[ui]
+ && new_reg_base_value[ui] != reg_base_value[ui]
+ && ! rtx_equal_p (new_reg_base_value[ui], reg_base_value[ui]))
{
- reg_base_value[i] = new_reg_base_value[i];
+ reg_base_value[ui] = new_reg_base_value[ui];
changed = 1;
}
}
{
changed = 0;
pass++;
- for (i = 0; i < reg_base_value_size; i++)
+ for (ui = 0; ui < reg_base_value_size; ui++)
{
- rtx base = reg_base_value[i];
+ rtx base = reg_base_value[ui];
if (base && GET_CODE (base) == REG)
{
- int base_regno = REGNO (base);
- if (base_regno == i) /* register set from itself */
- reg_base_value[i] = 0;
+ unsigned int base_regno = REGNO (base);
+ if (base_regno == ui) /* register set from itself */
+ reg_base_value[ui] = 0;
else
- reg_base_value[i] = reg_base_value[base_regno];
+ reg_base_value[ui] = reg_base_value[base_regno];
changed = 1;
}
}
}
while (changed && pass < MAX_ALIAS_LOOP_PASSES);
+ /* Clean up. */
+ free (new_reg_base_value);
new_reg_base_value = 0;
+ free (reg_seen);
reg_seen = 0;
}
void
end_alias_analysis ()
{
+ free (reg_known_value + FIRST_PSEUDO_REGISTER);
reg_known_value = 0;
- reg_base_value = 0;
+ reg_known_value_size = 0;
+ free (reg_known_equiv_p + FIRST_PSEUDO_REGISTER);
+ reg_known_equiv_p = 0;
+ if (reg_base_value)
+ {
+ if (ggc_p)
+ ggc_del_root (reg_base_value);
+ free (reg_base_value);
+ reg_base_value = 0;
+ }
reg_base_value_size = 0;
+ if (alias_invariant)
+ {
+ free (alias_invariant);
+ alias_invariant = 0;
+ }
}
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