Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
Contributed by John Carr (jfc@mit.edu).
-This file is part of GNU CC.
+This file is part of GCC.
-GNU CC is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
-GNU CC is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
You should have received a copy of the GNU General Public License
-along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+along with GCC; see the file COPYING. If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA. */
#include "config.h"
#include "system.h"
#include "cselib.h"
#include "splay-tree.h"
#include "ggc.h"
+#include "langhooks.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
To see whether two alias sets can point to the same memory, we must
see if either alias set is a subset of the other. We need not trace
- past immediate decendents, however, since we propagate all
+ past immediate descendents, however, since we propagate all
grandchildren up one level.
Alias set zero is implicitly a superset of all other alias sets.
HOST_WIDE_INT alias_set;
/* The children of the alias set. These are not just the immediate
- children, but, in fact, all decendents. So, if we have:
+ children, but, in fact, all descendents. So, if we have:
struct T { struct S s; float f; }
static int base_alias_check PARAMS ((rtx, rtx, enum machine_mode,
enum machine_mode));
static int handled_component_p PARAMS ((tree));
-static int can_address_p PARAMS ((tree));
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 tree find_base_decl PARAMS ((tree));
+static tree find_base_decl PARAMS ((tree));
static alias_set_entry get_alias_set_entry PARAMS ((HOST_WIDE_INT));
static rtx fixed_scalar_and_varying_struct_p PARAMS ((rtx, rtx, rtx, rtx,
int (*) (rtx, int)));
static int write_dependence_p PARAMS ((rtx, rtx, int));
static int nonlocal_mentioned_p PARAMS ((rtx));
-static int loop_p PARAMS ((void));
-
/* Set up all info needed to perform alias analysis on memory references. */
/* Returns the size in bytes of the mode of X. */
!= (t2 != 0 && AGGREGATE_TYPE_P (t2)))
return 0;
- /* Otherwise they conflict only if the alias sets conflict. */
+ /* Otherwise they conflict only if the alias sets conflict. */
return alias_sets_conflict_p (t1 ? get_alias_set (t1) : 0,
t2 ? get_alias_set (t2) : 0);
}
/* T is an expression with pointer type. Find the DECL on which this
expression is based. (For example, in `a[i]' this would be `a'.)
If there is no such DECL, or a unique decl cannot be determined,
- NULL_TREE is retured. */
+ NULL_TREE is returned. */
static tree
find_base_decl (t)
case '3':
d0 = find_base_decl (TREE_OPERAND (t, 0));
d1 = find_base_decl (TREE_OPERAND (t, 1));
- d0 = find_base_decl (TREE_OPERAND (t, 0));
d2 = find_base_decl (TREE_OPERAND (t, 2));
/* Set any nonzero values from the last, then from the first. */
/* Return 1 if all the nested component references handled by
get_inner_reference in T are such that we can address the object in T. */
-static int
+int
can_address_p (t)
tree t;
{
else if (TREE_CODE (t) == BIT_FIELD_REF)
return 0;
+ /* Fields are addressable unless they are marked as nonaddressable or
+ the containing type has alias set 0. */
else if (TREE_CODE (t) == COMPONENT_REF
&& ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))
+ && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0
&& can_address_p (TREE_OPERAND (t, 0)))
return 1;
+ /* Likewise for arrays. */
else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
&& ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))
+ && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0
&& can_address_p (TREE_OPERAND (t, 0)))
return 1;
get_alias_set (t)
tree t;
{
- tree orig_t;
HOST_WIDE_INT set;
/* If we're not doing any alias analysis, just assume everything
return 0;
/* We can be passed either an expression or a type. This and the
- language-specific routine may make mutually-recursive calls to
- each other to figure out what to do. At each juncture, we see if
- this is a tree that the language may need to handle specially.
- First handle things that aren't types and start by removing nops
- since we care only about the actual object. */
+ language-specific routine may make mutually-recursive calls to each other
+ to figure out what to do. At each juncture, we see if this is a tree
+ that the language may need to handle specially. First handle things that
+ aren't types. */
if (! TYPE_P (t))
{
- while (TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR
- || TREE_CODE (t) == NON_LVALUE_EXPR)
- t = TREE_OPERAND (t, 0);
-
- /* Now give the language a chance to do something but record what we
- gave it this time. */
- orig_t = t;
- if ((set = lang_get_alias_set (t)) != -1)
+ tree inner = t;
+ tree placeholder_ptr = 0;
+
+ /* Remove any nops, then give the language a chance to do
+ something with this tree before we look at it. */
+ STRIP_NOPS (t);
+ set = (*lang_hooks.get_alias_set) (t);
+ if (set != -1)
return set;
- /* Now loop the same way as get_inner_reference and get the alias
- set to use. Pick up the outermost object that we could have
- a pointer to. */
- while (handled_component_p (t) && ! can_address_p (t))
- t = TREE_OPERAND (t, 0);
+ /* First see if the actual object referenced is an INDIRECT_REF from a
+ restrict-qualified pointer or a "void *". Replace
+ PLACEHOLDER_EXPRs. */
+ while (TREE_CODE (inner) == PLACEHOLDER_EXPR
+ || handled_component_p (inner))
+ {
+ if (TREE_CODE (inner) == PLACEHOLDER_EXPR)
+ inner = find_placeholder (inner, &placeholder_ptr);
+ else
+ inner = TREE_OPERAND (inner, 0);
+
+ STRIP_NOPS (inner);
+ }
- if (TREE_CODE (t) == INDIRECT_REF)
+ /* Check for accesses through restrict-qualified pointers. */
+ if (TREE_CODE (inner) == INDIRECT_REF)
{
- /* Check for accesses through restrict-qualified pointers. */
- tree decl = find_base_decl (TREE_OPERAND (t, 0));
+ tree decl = find_base_decl (TREE_OPERAND (inner, 0));
if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl))
- /* We use the alias set indicated in the declaration. */
- return DECL_POINTER_ALIAS_SET (decl);
+ {
+ /* If we haven't computed the actual alias set, do it now. */
+ if (DECL_POINTER_ALIAS_SET (decl) == -2)
+ {
+ /* No two restricted pointers can point at the same thing.
+ However, a restricted pointer can point at the same thing
+ as an unrestricted pointer, if that unrestricted pointer
+ is based on the restricted pointer. So, we make the
+ alias set for the restricted pointer a subset of the
+ alias set for the type pointed to by the type of the
+ decl. */
+ HOST_WIDE_INT pointed_to_alias_set
+ = get_alias_set (TREE_TYPE (TREE_TYPE (decl)));
+
+ if (pointed_to_alias_set == 0)
+ /* It's not legal to make a subset of alias set zero. */
+ ;
+ else
+ {
+ DECL_POINTER_ALIAS_SET (decl) = new_alias_set ();
+ record_alias_subset (pointed_to_alias_set,
+ DECL_POINTER_ALIAS_SET (decl));
+ }
+ }
+
+ /* We use the alias set indicated in the declaration. */
+ return DECL_POINTER_ALIAS_SET (decl);
+ }
/* If we have an INDIRECT_REF via a void pointer, we don't
know anything about what that might alias. */
- if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE)
+ else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE)
return 0;
}
- /* Give the language another chance to do something special. */
- if (orig_t != t
- && (set = lang_get_alias_set (t)) != -1)
- return set;
+ /* Otherwise, pick up the outermost object that we could have a pointer
+ to, processing conversion and PLACEHOLDER_EXPR as above. */
+ placeholder_ptr = 0;
+ while (TREE_CODE (t) == PLACEHOLDER_EXPR
+ || (handled_component_p (t) && ! can_address_p (t)))
+ {
+ if (TREE_CODE (t) == PLACEHOLDER_EXPR)
+ t = find_placeholder (t, &placeholder_ptr);
+ else
+ t = TREE_OPERAND (t, 0);
+
+ STRIP_NOPS (t);
+ }
+
+ /* If we've already determined the alias set for a decl, just return
+ it. This is necessary for C++ anonymous unions, whose component
+ variables don't look like union members (boo!). */
+ if (TREE_CODE (t) == VAR_DECL
+ && DECL_RTL_SET_P (t) && GET_CODE (DECL_RTL (t)) == MEM)
+ return MEM_ALIAS_SET (DECL_RTL (t));
/* Now all we care about is the type. */
t = TREE_TYPE (t);
/* Variant qualifiers don't affect the alias set, so get the main
variant. If this is a type with a known alias set, return it. */
t = TYPE_MAIN_VARIANT (t);
- if (TYPE_P (t) && TYPE_ALIAS_SET_KNOWN_P (t))
+ if (TYPE_ALIAS_SET_KNOWN_P (t))
return TYPE_ALIAS_SET (t);
/* See if the language has special handling for this type. */
- if ((set = lang_get_alias_set (t)) != -1)
- {
- /* If the alias set is now known, we are done. */
- if (TYPE_ALIAS_SET_KNOWN_P (t))
- return TYPE_ALIAS_SET (t);
- }
+ set = (*lang_hooks.get_alias_set) (t);
+ if (set != -1)
+ return set;
/* There are no objects of FUNCTION_TYPE, so there's no point in
using up an alias set for them. (There are, of course, pointers
alias_set_entry superset_entry;
alias_set_entry subset_entry;
+ /* It is possible in complex type situations for both sets to be the same,
+ in which case we can ignore this operation. */
+ if (superset == subset)
+ return;
+
if (superset == 0)
abort ();
static rtx
find_base_value (src)
- register rtx src;
+ rtx src;
{
unsigned int regno;
switch (GET_CODE (src))
if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
break;
- /* ... fall through ... */
+ /* ... fall through ... */
case PLUS:
case MINUS:
case AND:
/* If the second operand is constant set the base
- address to the first operand. */
+ address to the first operand. */
if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0)
return find_base_value (XEXP (src, 0));
return 0;
rtx dest, set;
void *data ATTRIBUTE_UNUSED;
{
- register unsigned regno;
+ unsigned regno;
rtx src;
if (GET_CODE (dest) != REG)
reg_base_value[regno] = find_base_value (val);
}
+/* Clear alias info for a register. This is used if an RTL transformation
+ changes the value of a register. This is used in flow by AUTO_INC_DEC
+ optimizations. We don't need to clear reg_base_value, since flow only
+ changes the offset. */
+
+void
+clear_reg_alias_info (reg)
+ rtx reg;
+{
+ unsigned int regno = REGNO (reg);
+
+ if (regno < reg_known_value_size && regno >= FIRST_PSEUDO_REGISTER)
+ reg_known_value[regno] = reg;
+}
+
/* 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
MEM alone, but need to return the canonicalized MEM with
all the flags with their original values. */
else if (GET_CODE (x) == MEM)
- {
- rtx addr = canon_rtx (XEXP (x, 0));
+ x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0)));
- if (addr != XEXP (x, 0))
- {
- rtx new = gen_rtx_MEM (GET_MODE (x), addr);
-
- MEM_COPY_ATTRIBUTES (new, x);
- x = new;
- }
- }
return x;
}
rtx_equal_for_memref_p (x, y)
rtx x, y;
{
- register int i;
- register int j;
- register enum rtx_code code;
- register const char *fmt;
+ int i;
+ int j;
+ enum rtx_code code;
+ const char *fmt;
if (x == 0 && y == 0)
return 1;
/* Some RTL can be compared without a recursive examination. */
switch (code)
{
+ case VALUE:
+ return CSELIB_VAL_PTR (x) == CSELIB_VAL_PTR (y);
+
case REG:
return REGNO (x) == REGNO (y);
return 0;
break;
+ /* This can happen for asm operands. */
+ case 's':
+ if (strcmp (XSTR (x, i), XSTR (y, i)))
+ return 0;
+ break;
+
/* This can happen for an asm which clobbers memory. */
case '0':
break;
find_symbolic_term (x)
rtx x;
{
- register int i;
- register enum rtx_code code;
- register const char *fmt;
+ int i;
+ enum rtx_code code;
+ const char *fmt;
code = GET_CODE (x);
if (code == SYMBOL_REF || code == LABEL_REF)
static rtx
find_base_term (x)
- register rtx x;
+ rtx x;
{
cselib_val *val;
struct elt_loc_list *l;
rtx tmp1 = XEXP (x, 0);
rtx tmp2 = XEXP (x, 1);
- /* This is a litle bit tricky since we have to determine which of
+ /* This is a little 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.
if (flag_argument_noalias > 1)
return 0;
- /* Weak noalias assertion (arguments are distinct, but may match globals). */
+ /* Weak noalias assertion (arguments are distinct, but may match globals). */
return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode);
}
static int
memrefs_conflict_p (xsize, x, ysize, y, c)
- register rtx x, y;
+ rtx x, y;
int xsize, ysize;
HOST_WIDE_INT c;
{
rtx x;
int (*varies) PARAMS ((rtx, int));
{
- register rtx x_addr, mem_addr;
+ rtx x_addr, mem_addr;
rtx base;
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
if (aliases_everything_p (x))
return 1;
- /* We cannot use aliases_everyting_p to test MEM, since we must look
+ /* We cannot use aliases_everything_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;
}
/* Canonical true dependence: X is read after store in MEM takes place.
- Variant of true_dependece which assumes MEM has already been
+ Variant of true_dependence which assumes MEM has already been
canonicalized (hence we no longer do that here).
The mem_addr argument has been added, since true_dependence computed
this value prior to canonicalizing. */
enum machine_mode mem_mode;
int (*varies) PARAMS ((rtx, int));
{
- register rtx x_addr;
+ rtx x_addr;
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
return 1;
if (aliases_everything_p (x))
return 1;
- /* We cannot use aliases_everyting_p to test MEM, since we must look
+ /* We cannot use aliases_everything_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;
int
output_dependence (mem, x)
- register rtx mem;
- register rtx x;
+ rtx mem;
+ rtx x;
{
return write_dependence_p (mem, x, /*writep=*/1);
}
rtx x;
{
rtx base;
- register RTX_CODE code;
+ RTX_CODE code;
int regno;
code = GET_CODE (x);
{
/* Constant functions can be constant if they don't use
scratch memory used to mark function w/o side effects. */
- if (code == CALL_INSN && CONST_CALL_P (x))
+ if (code == CALL_INSN && CONST_OR_PURE_CALL_P (x))
{
x = CALL_INSN_FUNCTION_USAGE (x);
if (x == 0)
/* Recursively scan the operands of this expression. */
{
- register const char *fmt = GET_RTX_FORMAT (code);
- register int i;
+ const char *fmt = GET_RTX_FORMAT (code);
+ int i;
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
}
else if (fmt[i] == 'E')
{
- register int j;
+ int j;
for (j = 0; j < XVECLEN (x, i); j++)
if (nonlocal_mentioned_p (XVECEXP (x, i, j)))
return 1;
return 0;
}
-/* Return non-zero if a loop (natural or otherwise) is present.
- Inspired by Depth_First_Search_PP described in:
-
- Advanced Compiler Design and Implementation
- Steven Muchnick
- Morgan Kaufmann, 1997
-
- and heavily borrowed from flow_depth_first_order_compute. */
-
-static int
-loop_p ()
-{
- edge *stack;
- int *pre;
- int *post;
- int sp;
- int prenum = 1;
- int postnum = 1;
- sbitmap visited;
-
- /* Allocate the preorder and postorder number arrays. */
- pre = (int *) xcalloc (n_basic_blocks, sizeof (int));
- post = (int *) xcalloc (n_basic_blocks, sizeof (int));
-
- /* Allocate stack for back-tracking up CFG. */
- stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
- sp = 0;
-
- /* Allocate bitmap to track nodes that have been visited. */
- visited = sbitmap_alloc (n_basic_blocks);
-
- /* None of the nodes in the CFG have been visited yet. */
- sbitmap_zero (visited);
-
- /* Push the first edge on to the stack. */
- stack[sp++] = ENTRY_BLOCK_PTR->succ;
-
- while (sp)
- {
- edge e;
- basic_block src;
- basic_block dest;
-
- /* Look at the edge on the top of the stack. */
- e = stack[sp - 1];
- src = e->src;
- dest = e->dest;
-
- /* Check if the edge destination has been visited yet. */
- if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
- {
- /* Mark that we have visited the destination. */
- SET_BIT (visited, dest->index);
-
- pre[dest->index] = prenum++;
-
- if (dest->succ)
- {
- /* Since the DEST node has been visited for the first
- time, check its successors. */
- stack[sp++] = dest->succ;
- }
- else
- post[dest->index] = postnum++;
- }
- else
- {
- if (dest != EXIT_BLOCK_PTR
- && pre[src->index] >= pre[dest->index]
- && post[dest->index] == 0)
- break;
-
- if (! e->succ_next && src != ENTRY_BLOCK_PTR)
- post[src->index] = postnum++;
-
- if (e->succ_next)
- stack[sp - 1] = e->succ_next;
- else
- sp--;
- }
- }
-
- free (pre);
- free (post);
- free (stack);
- sbitmap_free (visited);
-
- return sp;
-}
-
/* Mark the function if it is constant. */
void
return;
/* A loop might not return which counts as a side effect. */
- if (loop_p ())
+ if (mark_dfs_back_edges ())
return;
nonlocal_mentioned = 0;
void
init_alias_once ()
{
- register int i;
+ int i;
#ifndef OUTGOING_REGNO
#define OUTGOING_REGNO(N) N
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
/* Check whether this register can hold an incoming pointer
argument. FUNCTION_ARG_REGNO_P tests outgoing register
- numbers, so translate if necessary due to register windows. */
+ numbers, so translate if necessary due to register windows. */
if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i))
&& HARD_REGNO_MODE_OK (i, Pmode))
SET_HARD_REG_BIT (argument_registers, i);
{
int maxreg = max_reg_num ();
int changed, pass;
- register int i;
- register unsigned int ui;
- register rtx insn;
+ int i;
+ unsigned int ui;
+ rtx insn;
reg_known_value_size = maxreg;
start counting from zero each iteration of the loop. */
unique_id = 0;
- /* We're at the start of the funtion each iteration through the
+ /* We're at the start of the function each iteration through the
loop, so we're copying arguments. */
copying_arguments = 1;
rtx note, set;
#if defined (HAVE_prologue) || defined (HAVE_epilogue)
- /* The prologue/epilouge insns are not threaded onto the
+ /* The prologue/epilogue insns are not threaded onto the
insn chain until after reload has completed. Thus,
there is no sense wasting time checking if INSN is in
the prologue/epilogue until after reload has completed. */
/* If this insn has a noalias note, process it, Otherwise,
scan for sets. A simple set will have no side effects
- which could change the base value of any other register. */
+ which could change the base value of any other register. */
if (GET_CODE (PATTERN (insn)) == SET
&& REG_NOTES (insn) != 0
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