[2/2] passes: Move early pass_sccopy right after evrp [PR103221]
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Commit Message
EVRP changes some statements into copies but then does
not do copy prop during its handling. This causes in some
cases where phiopt could have optimized the phi not to be
done. So we should move the copy prop pass (sccopy) right
after evrp instead of after phiopt.
Notes on the testsuite changes:
dse-points-to.c needs to disable sccopy1 for the same
reason why it disables all other copyprop passes.
pr45397.c had an xfail for specifically PR 103221.
pr81981.c is about a missing warning, in this case moving
sccopy swaps around which uses is first in the list.
Bootstrapped and tested on x86_64-linux-gnu.
PR tree-optimization/103221
gcc/ChangeLog:
* passes.def (early_optimizations): Move sccopy
to after evrp.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/dse-points-to.c: Disable sccopy1.
* gcc.dg/tree-ssa/pr45397.c: Remove the xfail.
* gcc.dg/ubsan/pr81981.c: Swap around which one is xfailed.
Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
---
gcc/passes.def | 2 +-
gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c | 2 +-
gcc/testsuite/gcc.dg/tree-ssa/pr45397.c | 8 +++-----
gcc/testsuite/gcc.dg/ubsan/pr81981.c | 4 ++--
4 files changed, 7 insertions(+), 9 deletions(-)
Comments
On Wed, Jun 3, 2026 at 4:07 AM Andrew Pinski
<andrew.pinski@oss.qualcomm.com> wrote:
>
> EVRP changes some statements into copies but then does
> not do copy prop during its handling. This causes in some
> cases where phiopt could have optimized the phi not to be
> done. So we should move the copy prop pass (sccopy) right
> after evrp instead of after phiopt.
>
> Notes on the testsuite changes:
> dse-points-to.c needs to disable sccopy1 for the same
> reason why it disables all other copyprop passes.
> pr45397.c had an xfail for specifically PR 103221.
> pr81981.c is about a missing warning, in this case moving
> sccopy swaps around which uses is first in the list.
OK. I guess EVRP copies are more common than tail-recursion
introduced ones.
> Bootstrapped and tested on x86_64-linux-gnu.
>
> PR tree-optimization/103221
> gcc/ChangeLog:
>
> * passes.def (early_optimizations): Move sccopy
> to after evrp.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/dse-points-to.c: Disable sccopy1.
> * gcc.dg/tree-ssa/pr45397.c: Remove the xfail.
> * gcc.dg/ubsan/pr81981.c: Swap around which one is xfailed.
>
> Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
> ---
> gcc/passes.def | 2 +-
> gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c | 2 +-
> gcc/testsuite/gcc.dg/tree-ssa/pr45397.c | 8 +++-----
> gcc/testsuite/gcc.dg/ubsan/pr81981.c | 4 ++--
> 4 files changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/gcc/passes.def b/gcc/passes.def
> index cdddb87302f..1fc867fae51 100644
> --- a/gcc/passes.def
> +++ b/gcc/passes.def
> @@ -94,6 +94,7 @@ along with GCC; see the file COPYING3. If not see
> NEXT_PASS (pass_phiprop);
> NEXT_PASS (pass_fre, true /* may_iterate */);
> NEXT_PASS (pass_early_vrp);
> + NEXT_PASS (pass_sccopy);
> NEXT_PASS (pass_merge_phi);
> NEXT_PASS (pass_dse);
> NEXT_PASS (pass_cd_dce, false /* update_address_taken_p */, true /* remove_unused_locals */);
> @@ -104,7 +105,6 @@ along with GCC; see the file COPYING3. If not see
> NEXT_PASS (pass_tail_recursion);
> NEXT_PASS (pass_if_to_switch);
> NEXT_PASS (pass_convert_switch);
> - NEXT_PASS (pass_sccopy);
> NEXT_PASS (pass_profile);
> NEXT_PASS (pass_local_pure_const);
> NEXT_PASS (pass_modref);
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c b/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c
> index 762d6720143..ff84ba8db13 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O2 -fno-tree-ccp -fno-tree-forwprop -fno-tree-fre -fno-tree-vrp -fdump-tree-dse1-details" } */
> +/* { dg-options "-O2 -fno-tree-ccp -fno-tree-forwprop -fno-tree-fre -fno-tree-vrp -fdisable-tree-sccopy1 -fdump-tree-dse1-details" } */
>
> int
> f ()
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c b/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c
> index 8eacb518777..37e57a8996c 100644
> --- a/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c
> @@ -18,12 +18,10 @@ int foo_mul (const unsigned char *tmp, int i, int val)
>
> /* All cases should end up using min/max for the saturated operations and
> have no control flow. */
> -/* EVRP leaves copies in the IL which confuses phiopt1 so we have
> - to rely on phiopt2 instead. */
> /* { dg-final { scan-tree-dump-not " & 255;" "evrp" } } */
> -/* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt1" { xfail *-*-* } } } */
> -/* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt1" { xfail *-*-* } } } */
> -/* { dg-final { scan-tree-dump-not "if " "phiopt1" { xfail *-*-* } } } */
> +/* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt1" } } */
> +/* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt1" } } */
> +/* { dg-final { scan-tree-dump-not "if " "phiopt1" } } */
> /* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt2" } } */
> /* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt2" } } */
> /* { dg-final { scan-tree-dump-not "if " "phiopt2" } } */
> diff --git a/gcc/testsuite/gcc.dg/ubsan/pr81981.c b/gcc/testsuite/gcc.dg/ubsan/pr81981.c
> index d201efb3f65..8aac5ae9725 100644
> --- a/gcc/testsuite/gcc.dg/ubsan/pr81981.c
> +++ b/gcc/testsuite/gcc.dg/ubsan/pr81981.c
> @@ -16,6 +16,6 @@ foo (int i)
> u[0] = i;
> }
>
> - v = u[0]; /* { dg-warning "may be used uninitialized" "" { xfail *-*-* } } */
> - return t[0]; /* { dg-warning "may be used uninitialized" } */
> + v = u[0]; /* { dg-warning "may be used uninitialized" } */
> + return t[0]; /* { dg-warning "may be used uninitialized" "" { xfail *-*-* } } */
> }
> --
> 2.43.0
>
On Wed, Jun 3, 2026 at 4:43 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Wed, Jun 3, 2026 at 4:07 AM Andrew Pinski
> <andrew.pinski@oss.qualcomm.com> wrote:
> >
> > EVRP changes some statements into copies but then does
> > not do copy prop during its handling. This causes in some
> > cases where phiopt could have optimized the phi not to be
> > done. So we should move the copy prop pass (sccopy) right
> > after evrp instead of after phiopt.
> >
> > Notes on the testsuite changes:
> > dse-points-to.c needs to disable sccopy1 for the same
> > reason why it disables all other copyprop passes.
> > pr45397.c had an xfail for specifically PR 103221.
> > pr81981.c is about a missing warning, in this case moving
> > sccopy swaps around which uses is first in the list.
>
> OK. I guess EVRP copies are more common than tail-recursion
> introduced ones.
Yes, that is correct.
And the inliner will produce more copies. ccp right after inlining
will remove most of those and so will forwprop right before alias
pass.
Thanks,
Andrea
>
> > Bootstrapped and tested on x86_64-linux-gnu.
> >
> > PR tree-optimization/103221
> > gcc/ChangeLog:
> >
> > * passes.def (early_optimizations): Move sccopy
> > to after evrp.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.dg/tree-ssa/dse-points-to.c: Disable sccopy1.
> > * gcc.dg/tree-ssa/pr45397.c: Remove the xfail.
> > * gcc.dg/ubsan/pr81981.c: Swap around which one is xfailed.
> >
> > Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
> > ---
> > gcc/passes.def | 2 +-
> > gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c | 2 +-
> > gcc/testsuite/gcc.dg/tree-ssa/pr45397.c | 8 +++-----
> > gcc/testsuite/gcc.dg/ubsan/pr81981.c | 4 ++--
> > 4 files changed, 7 insertions(+), 9 deletions(-)
> >
> > diff --git a/gcc/passes.def b/gcc/passes.def
> > index cdddb87302f..1fc867fae51 100644
> > --- a/gcc/passes.def
> > +++ b/gcc/passes.def
> > @@ -94,6 +94,7 @@ along with GCC; see the file COPYING3. If not see
> > NEXT_PASS (pass_phiprop);
> > NEXT_PASS (pass_fre, true /* may_iterate */);
> > NEXT_PASS (pass_early_vrp);
> > + NEXT_PASS (pass_sccopy);
> > NEXT_PASS (pass_merge_phi);
> > NEXT_PASS (pass_dse);
> > NEXT_PASS (pass_cd_dce, false /* update_address_taken_p */, true /* remove_unused_locals */);
> > @@ -104,7 +105,6 @@ along with GCC; see the file COPYING3. If not see
> > NEXT_PASS (pass_tail_recursion);
> > NEXT_PASS (pass_if_to_switch);
> > NEXT_PASS (pass_convert_switch);
> > - NEXT_PASS (pass_sccopy);
> > NEXT_PASS (pass_profile);
> > NEXT_PASS (pass_local_pure_const);
> > NEXT_PASS (pass_modref);
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c b/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c
> > index 762d6720143..ff84ba8db13 100644
> > --- a/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/dse-points-to.c
> > @@ -1,5 +1,5 @@
> > /* { dg-do compile } */
> > -/* { dg-options "-O2 -fno-tree-ccp -fno-tree-forwprop -fno-tree-fre -fno-tree-vrp -fdump-tree-dse1-details" } */
> > +/* { dg-options "-O2 -fno-tree-ccp -fno-tree-forwprop -fno-tree-fre -fno-tree-vrp -fdisable-tree-sccopy1 -fdump-tree-dse1-details" } */
> >
> > int
> > f ()
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c b/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c
> > index 8eacb518777..37e57a8996c 100644
> > --- a/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr45397.c
> > @@ -18,12 +18,10 @@ int foo_mul (const unsigned char *tmp, int i, int val)
> >
> > /* All cases should end up using min/max for the saturated operations and
> > have no control flow. */
> > -/* EVRP leaves copies in the IL which confuses phiopt1 so we have
> > - to rely on phiopt2 instead. */
> > /* { dg-final { scan-tree-dump-not " & 255;" "evrp" } } */
> > -/* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt1" { xfail *-*-* } } } */
> > -/* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt1" { xfail *-*-* } } } */
> > -/* { dg-final { scan-tree-dump-not "if " "phiopt1" { xfail *-*-* } } } */
> > +/* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt1" } } */
> > +/* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt1" } } */
> > +/* { dg-final { scan-tree-dump-not "if " "phiopt1" } } */
> > /* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt2" } } */
> > /* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt2" } } */
> > /* { dg-final { scan-tree-dump-not "if " "phiopt2" } } */
> > diff --git a/gcc/testsuite/gcc.dg/ubsan/pr81981.c b/gcc/testsuite/gcc.dg/ubsan/pr81981.c
> > index d201efb3f65..8aac5ae9725 100644
> > --- a/gcc/testsuite/gcc.dg/ubsan/pr81981.c
> > +++ b/gcc/testsuite/gcc.dg/ubsan/pr81981.c
> > @@ -16,6 +16,6 @@ foo (int i)
> > u[0] = i;
> > }
> >
> > - v = u[0]; /* { dg-warning "may be used uninitialized" "" { xfail *-*-* } } */
> > - return t[0]; /* { dg-warning "may be used uninitialized" } */
> > + v = u[0]; /* { dg-warning "may be used uninitialized" } */
> > + return t[0]; /* { dg-warning "may be used uninitialized" "" { xfail *-*-* } } */
> > }
> > --
> > 2.43.0
> >
@@ -94,6 +94,7 @@ along with GCC; see the file COPYING3. If not see
NEXT_PASS (pass_phiprop);
NEXT_PASS (pass_fre, true /* may_iterate */);
NEXT_PASS (pass_early_vrp);
+ NEXT_PASS (pass_sccopy);
NEXT_PASS (pass_merge_phi);
NEXT_PASS (pass_dse);
NEXT_PASS (pass_cd_dce, false /* update_address_taken_p */, true /* remove_unused_locals */);
@@ -104,7 +105,6 @@ along with GCC; see the file COPYING3. If not see
NEXT_PASS (pass_tail_recursion);
NEXT_PASS (pass_if_to_switch);
NEXT_PASS (pass_convert_switch);
- NEXT_PASS (pass_sccopy);
NEXT_PASS (pass_profile);
NEXT_PASS (pass_local_pure_const);
NEXT_PASS (pass_modref);
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -fno-tree-ccp -fno-tree-forwprop -fno-tree-fre -fno-tree-vrp -fdump-tree-dse1-details" } */
+/* { dg-options "-O2 -fno-tree-ccp -fno-tree-forwprop -fno-tree-fre -fno-tree-vrp -fdisable-tree-sccopy1 -fdump-tree-dse1-details" } */
int
f ()
@@ -18,12 +18,10 @@ int foo_mul (const unsigned char *tmp, int i, int val)
/* All cases should end up using min/max for the saturated operations and
have no control flow. */
-/* EVRP leaves copies in the IL which confuses phiopt1 so we have
- to rely on phiopt2 instead. */
/* { dg-final { scan-tree-dump-not " & 255;" "evrp" } } */
-/* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt1" { xfail *-*-* } } } */
-/* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt1" { xfail *-*-* } } } */
-/* { dg-final { scan-tree-dump-not "if " "phiopt1" { xfail *-*-* } } } */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-not "if " "phiopt1" } } */
/* { dg-final { scan-tree-dump-times "MAX_EXPR" 3 "phiopt2" } } */
/* { dg-final { scan-tree-dump-times "MIN_EXPR" 3 "phiopt2" } } */
/* { dg-final { scan-tree-dump-not "if " "phiopt2" } } */
@@ -16,6 +16,6 @@ foo (int i)
u[0] = i;
}
- v = u[0]; /* { dg-warning "may be used uninitialized" "" { xfail *-*-* } } */
- return t[0]; /* { dg-warning "may be used uninitialized" } */
+ v = u[0]; /* { dg-warning "may be used uninitialized" } */
+ return t[0]; /* { dg-warning "may be used uninitialized" "" { xfail *-*-* } } */
}