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re PR rtl-optimization/70484 (Wrong optimization with aliasing and access via char) 

2016-04-04  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/70484
	* rtl.h (canon_output_dependence): Declare.
	* alias.c (canon_output_dependence): New function.
	* dse.c (record_store): Use canon_output_dependence rather
	than canon_true_dependence.

	* gcc.dg/torture/pr70484.c: New testcase.

From-SVN: r234709
This commit is contained in:
Richard Biener 2016-04-04 09:30:16 +00:00 committed by Richard Biener
parent ed2a53e7ca
commit 43b9f49910
6 changed files with 51 additions and 4 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2016-04-04 Richard Biener <rguenther@suse.de>
PR rtl-optimization/70484
* rtl.h (canon_output_dependence): Declare.
* alias.c (canon_output_dependence): New function.
* dse.c (record_store): Use canon_output_dependence rather
than canon_true_dependence.
2016-03-30 Jan Hubicka <hubicka@ucw.cz>
PR ipa/68881

14
gcc/alias.c
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@ -3057,6 +3057,20 @@ output_dependence (const_rtx mem, const_rtx x)
/*mem_canonicalized=*/false,
/*x_canonicalized*/false, /*writep=*/true);
}
/* Likewise, but we already have a canonicalized MEM, and X_ADDR for X.
Also, consider X in X_MODE (which might be from an enclosing
STRICT_LOW_PART / ZERO_EXTRACT).
If MEM_CANONICALIZED is true, MEM is canonicalized. */
int
canon_output_dependence (const_rtx mem, bool mem_canonicalized,
const_rtx x, machine_mode x_mode, rtx x_addr)
{
return write_dependence_p (mem, x, x_mode, x_addr,
mem_canonicalized, /*x_canonicalized=*/true,
/*writep=*/true);
}

7
gcc/dse.c
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@ -1609,10 +1609,9 @@ record_store (rtx body, bb_info_t bb_info)
the value of store_info. If it is, set the rhs to NULL to
keep it from being used to remove a load. */
{
if (canon_true_dependence (s_info->mem,
GET_MODE (s_info->mem),
s_info->mem_addr,
mem, mem_addr))
if (canon_output_dependence (s_info->mem, true,
mem, GET_MODE (mem),
mem_addr))
{
s_info->rhs = NULL;
s_info->const_rhs = NULL;

2
gcc/rtl.h
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@ -3652,6 +3652,8 @@ extern int anti_dependence (const_rtx, const_rtx);
extern int canon_anti_dependence (const_rtx, bool,
const_rtx, machine_mode, rtx);
extern int output_dependence (const_rtx, const_rtx);
extern int canon_output_dependence (const_rtx, bool,
const_rtx, machine_mode, rtx);
extern int may_alias_p (const_rtx, const_rtx);
extern void init_alias_target (void);
extern void init_alias_analysis (void);

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-04-04 Richard Biener <rguenther@suse.de>
PR rtl-optimization/70484
* gcc.dg/torture/pr70484.c: New testcase.
2016-04-04 Marek Polacek <polacek@redhat.com>
PR c/70307

19
gcc/testsuite/gcc.dg/torture/pr70484.c Normal file
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@ -0,0 +1,19 @@
/* { dg-do run } */
extern void abort (void);
int __attribute__((noinline,noclone))
f(int *pi, long *pl)
{
*pi = 1;
*pl = 0;
return *(char *)pi;
}
int main()
{
union { long l; int i; } a;
if (f (&a.i, &a.l) != 0)
abort ();
return 0;
}