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re PR tree-optimization/21574 (store_ccp doesn't see through a store.)

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PR tree-optimization/21574
	* tree-ssa-ccp.c (likely_value): If the right hand side is a
	constant, return CONSTANT.
	(ccp_lattice_meet): Use operand_equal_p instead of simple_cst_equal.
	(ccp_fold, visit_assignment): Likewise.
	(evaluate_stmt): Handle UNDEFINED and UNKNOWN_VAL the same way.

From-SVN: r103206
This commit is contained in:
Steven Bosscher 2005-08-17 07:27:47 +00:00 committed by Steven Bosscher
parent a7edd66b06
commit a318e3acf8
4 changed files with 41 additions and 4 deletions
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9
gcc/ChangeLog
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@ -1,3 +1,12 @@
2005-08-17 Steven Bosscher <stevenb@suse.de>
PR tree-optimization/21574
* tree-ssa-ccp.c (likely_value): If the right hand side is a
constant, return CONSTANT.
(ccp_lattice_meet): Use operand_equal_p instead of simple_cst_equal.
(ccp_fold, visit_assignment): Likewise.
(evaluate_stmt): Handle UNDEFINED and UNKNOWN_VAL the same way.
2005-08-16 James A. Morrison <phython@gcc.gnu.org>
* c-typeck.c (build_function_call): Call fold_buildN_initializer or

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2005-08-17 Steven Bosscher <stevenb@suse.de>
PR tree-optimization/21574
* gcc.dg/tree-ssa/pr21574.c: New test.
2005-08-16 James E Wilson <wilson@specifix.com>
* gcc.dg/large-size-array.c (DIM): Use USHRT_MAX not USHORT_MAX.

13
gcc/testsuite/gcc.dg/tree-ssa/pr21574.c Normal file
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@ -0,0 +1,13 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fno-tree-dominator-opts -fdump-tree-store_ccp" } */
int
foo (int *p)
{
*p = 0;
return *p;
}
/* The store to *p should be propagated to the return statement. */
/* { dg-final { scan-tree-dump-times "return 0" 1 "store_ccp" } } */
/* { dg-final { cleanup-tree-dump "store_ccp" } } */

18
gcc/tree-ssa-ccp.c
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@ -473,6 +473,9 @@ likely_value (tree stmt)
&& TREE_CODE (stmt) != SWITCH_EXPR)
return VARYING;
if (is_gimple_min_invariant (get_rhs (stmt)))
return CONSTANT;
found_constant = false;
FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE|SSA_OP_VUSE)
{
@ -658,7 +661,8 @@ ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2)
&& val2->lattice_val == CONSTANT
&& simple_cst_equal (val1->value, val2->value) == 1
&& (!do_store_ccp
|| simple_cst_equal (val1->mem_ref, val2->mem_ref) == 1))
|| (val1->mem_ref && val2->mem_ref
&& operand_equal_p (val1->mem_ref, val2->mem_ref, 0))))
{
/* Ci M Cj = Ci if (i == j)
Ci M Cj = VARYING if (i != j)
@ -826,7 +830,8 @@ ccp_fold (tree stmt)
/* If the RHS is a memory load, see if the VUSEs associated with
it are a valid constant for that memory load. */
prop_value_t *val = get_value_loaded_by (stmt, const_val);
if (val && simple_cst_equal (val->mem_ref, rhs) == 1)
if (val && val->mem_ref
&& operand_equal_p (val->mem_ref, rhs, 0))
return val->value;
else
return NULL_TREE;
@ -1085,7 +1090,11 @@ evaluate_stmt (tree stmt)
/* The statement produced a nonconstant value. If the statement
had UNDEFINED operands, then the result of the statement
should be UNDEFINED. Otherwise, the statement is VARYING. */
val.lattice_val = (likelyvalue == UNDEFINED) ? UNDEFINED : VARYING;
if (likelyvalue == UNDEFINED || likelyvalue == UNKNOWN_VAL)
val.lattice_val = likelyvalue;
else
val.lattice_val = VARYING;
val.value = NULL_TREE;
}
@ -1122,7 +1131,8 @@ visit_assignment (tree stmt, tree *output_p)
we can propagate the value on the RHS. */
prop_value_t *nval = get_value_loaded_by (stmt, const_val);
if (nval && simple_cst_equal (nval->mem_ref, rhs) == 1)
if (nval && nval->mem_ref
&& operand_equal_p (nval->mem_ref, rhs, 0))
val = *nval;
else
val = evaluate_stmt (stmt);