Re: Fix wrong code in ldist-strlen-1.c
On Sat, Oct 16, 2021 at 8:46 AM Richard Biener via Gcc-patches
wrote:
>
> On October 16, 2021 2:47:51 PM GMT+02:00, Jan Hubicka via Gcc-patches
> wrote:
> >Hi,
> >while updating compute_points_to_sets I missed that the code not only
> >sets the nonlocal/escaped flags but also initializes pt. With my
> >previous change if uses_global_memory is false pt is not updated
> >correctly which may lead to wrong code.
> >
> >This is fixed by the following patch I comitted to avoid strange
> >misoptimizations.
> >
> >Bootstrapped/regtested x86_64-linux and also tested with LTO.
This caused:
FAIL: gfortran.dg/deferred_type_param_6.f90 -O1 execution test
on Linux/x86-64. -march=cascadelake may be needed to reproduce it.
> OK.
>
> Richard.
>
> >Honza
> >
> >gcc/ChangeLog:
> >
> > PR tree-optimization/102720
> > * tree-ssa-structalias.c (compute_points_to_sets): Fix producing
> > of call used and clobbered sets.
> >
> >diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
> >index 6f12a66ee0d..2e6513bb72a 100644
> >--- a/gcc/tree-ssa-structalias.c
> >+++ b/gcc/tree-ssa-structalias.c
> >@@ -7541,17 +7541,18 @@ compute_points_to_sets (void)
> > determine_global_memory_access (stmt, NULL,
> > _global_memory,
> > _global_memory);
> >-if (!uses_global_memory)
> >- ;
> >-else if ((vi = lookup_call_use_vi (stmt)) != NULL)
> >+if ((vi = lookup_call_use_vi (stmt)) != NULL)
> > {
> > *pt = find_what_var_points_to (cfun->decl, vi);
> > /* Escaped (and thus nonlocal) variables are always
> >implicitly used by calls. */
> > /* ??? ESCAPED can be empty even though NONLOCAL
> >always escaped. */
> >-pt->nonlocal = uses_global_memory;
> >-pt->escaped = uses_global_memory;
> >+if (uses_global_memory)
> >+ {
> >+pt->nonlocal = uses_global_memory;
> >+pt->escaped = uses_global_memory;
> >+ }
> > }
> > else if (uses_global_memory)
> > {
> >@@ -7572,17 +7573,18 @@ compute_points_to_sets (void)
> > determine_global_memory_access (stmt, _global_memory,
> > NULL, NULL);
> >
> >-if (!writes_global_memory)
> >- ;
> >-else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
> >+if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
> > {
> > *pt = find_what_var_points_to (cfun->decl, vi);
> > /* Escaped (and thus nonlocal) variables are always
> >implicitly clobbered by calls. */
> > /* ??? ESCAPED can be empty even though NONLOCAL
> >always escaped. */
> >-pt->nonlocal = writes_global_memory;
> >-pt->escaped = writes_global_memory;
> >+if (writes_global_memory)
> >+ {
> >+pt->nonlocal = writes_global_memory;
> >+pt->escaped = writes_global_memory;
> >+ }
> > }
> > else if (writes_global_memory)
> > {
>
--
H.J.
Re: Fix wrong code in ldist-strlen-1.c
On October 16, 2021 2:47:51 PM GMT+02:00, Jan Hubicka via Gcc-patches
wrote:
>Hi,
>while updating compute_points_to_sets I missed that the code not only
>sets the nonlocal/escaped flags but also initializes pt. With my
>previous change if uses_global_memory is false pt is not updated
>correctly which may lead to wrong code.
>
>This is fixed by the following patch I comitted to avoid strange
>misoptimizations.
>
>Bootstrapped/regtested x86_64-linux and also tested with LTO.
OK.
Richard.
>Honza
>
>gcc/ChangeLog:
>
> PR tree-optimization/102720
> * tree-ssa-structalias.c (compute_points_to_sets): Fix producing
> of call used and clobbered sets.
>
>diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
>index 6f12a66ee0d..2e6513bb72a 100644
>--- a/gcc/tree-ssa-structalias.c
>+++ b/gcc/tree-ssa-structalias.c
>@@ -7541,17 +7541,18 @@ compute_points_to_sets (void)
> determine_global_memory_access (stmt, NULL,
> _global_memory,
> _global_memory);
>-if (!uses_global_memory)
>- ;
>-else if ((vi = lookup_call_use_vi (stmt)) != NULL)
>+if ((vi = lookup_call_use_vi (stmt)) != NULL)
> {
> *pt = find_what_var_points_to (cfun->decl, vi);
> /* Escaped (and thus nonlocal) variables are always
>implicitly used by calls. */
> /* ??? ESCAPED can be empty even though NONLOCAL
>always escaped. */
>-pt->nonlocal = uses_global_memory;
>-pt->escaped = uses_global_memory;
>+if (uses_global_memory)
>+ {
>+pt->nonlocal = uses_global_memory;
>+pt->escaped = uses_global_memory;
>+ }
> }
> else if (uses_global_memory)
> {
>@@ -7572,17 +7573,18 @@ compute_points_to_sets (void)
> determine_global_memory_access (stmt, _global_memory,
> NULL, NULL);
>
>-if (!writes_global_memory)
>- ;
>-else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
>+if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
> {
> *pt = find_what_var_points_to (cfun->decl, vi);
> /* Escaped (and thus nonlocal) variables are always
>implicitly clobbered by calls. */
> /* ??? ESCAPED can be empty even though NONLOCAL
>always escaped. */
>-pt->nonlocal = writes_global_memory;
>-pt->escaped = writes_global_memory;
>+if (writes_global_memory)
>+ {
>+pt->nonlocal = writes_global_memory;
>+pt->escaped = writes_global_memory;
>+ }
> }
> else if (writes_global_memory)
> {
Fix wrong code in ldist-strlen-1.c
Hi,
while updating compute_points_to_sets I missed that the code not only
sets the nonlocal/escaped flags but also initializes pt. With my
previous change if uses_global_memory is false pt is not updated
correctly which may lead to wrong code.
This is fixed by the following patch I comitted to avoid strange
misoptimizations.
Bootstrapped/regtested x86_64-linux and also tested with LTO.
Honza
gcc/ChangeLog:
PR tree-optimization/102720
* tree-ssa-structalias.c (compute_points_to_sets): Fix producing
of call used and clobbered sets.
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 6f12a66ee0d..2e6513bb72a 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -7541,17 +7541,18 @@ compute_points_to_sets (void)
determine_global_memory_access (stmt, NULL,
_global_memory,
_global_memory);
- if (!uses_global_memory)
- ;
- else if ((vi = lookup_call_use_vi (stmt)) != NULL)
+ if ((vi = lookup_call_use_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (cfun->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly used by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
- pt->nonlocal = uses_global_memory;
- pt->escaped = uses_global_memory;
+ if (uses_global_memory)
+ {
+ pt->nonlocal = uses_global_memory;
+ pt->escaped = uses_global_memory;
+ }
}
else if (uses_global_memory)
{
@@ -7572,17 +7573,18 @@ compute_points_to_sets (void)
determine_global_memory_access (stmt, _global_memory,
NULL, NULL);
- if (!writes_global_memory)
- ;
- else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
+ if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (cfun->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly clobbered by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
- pt->nonlocal = writes_global_memory;
- pt->escaped = writes_global_memory;
+ if (writes_global_memory)
+ {
+ pt->nonlocal = writes_global_memory;
+ pt->escaped = writes_global_memory;
+ }
}
else if (writes_global_memory)
{
