| Message ID | ZfQLuno+PsZ2WsNh@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | i386: Fix a pasto in ix86_expand_int_sse_cmp [PR114339] | expand |
On Fri, Mar 15, 2024 at 9:50 AM Jakub Jelinek <jakub@redhat.com> wrote: > > Hi! > > In r13-3803-gfa271afb58 I've added an optimization for LE/LEU/GE/GEU > comparison against CONST_VECTOR. As the comments say: > /* x <= cst can be handled as x < cst + 1 unless there is > wrap around in cst + 1. */ > ... > /* For LE punt if some element is signed maximum. */ > ... > /* For LEU punt if some element is unsigned maximum. */ > and > /* x >= cst can be handled as x > cst - 1 unless there is > wrap around in cst - 1. */ > ... > /* For GE punt if some element is signed minimum. */ > ... > /* For GEU punt if some element is zero. */ > Apparently I wrote the GE/GEU (second case) first and then > copied/adjusted it for LE/LEU, most of the adjustments look correct, but > I've left if (code == GE) comparison when testing if it should punt for > signed maximum. That condition is never true, because this is in > switch (code) { ... case LE: case LEU: block and we really meant to > be what the comment says, for LE punt if some element is signed maximum, > as then cst + 1 wraps around. > > The following patch fixes the pasto. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > 2024-03-15 Jakub Jelinek <jakub@redhat.com> > > PR target/114339 > * config/i386/i386-expand.cc (ix86_expand_int_sse_cmp) <case LE>: Fix > a pasto, compare code against LE rather than GE. > > * gcc.target/i386/pr114339.c: New test. OK. Thanks, Uros. > > --- gcc/config/i386/i386-expand.cc.jj 2024-03-07 08:34:21.043802912 +0100 > +++ gcc/config/i386/i386-expand.cc 2024-03-14 22:55:57.321842686 +0100 > @@ -4690,7 +4690,7 @@ ix86_expand_int_sse_cmp (rtx dest, enum > rtx elt = CONST_VECTOR_ELT (cop1, i); > if (!CONST_INT_P (elt)) > break; > - if (code == GE) > + if (code == LE) > { > /* For LE punt if some element is signed maximum. */ > if ((INTVAL (elt) & (GET_MODE_MASK (eltmode) >> 1)) > --- gcc/testsuite/gcc.target/i386/pr114339.c.jj 2024-03-14 22:58:04.739076025 +0100 > +++ gcc/testsuite/gcc.target/i386/pr114339.c 2024-03-14 22:38:59.736972124 +0100 > @@ -0,0 +1,20 @@ > +/* PR target/114339 */ > +/* { dg-do run } */ > +/* { dg-options "-O2 -Wno-psabi" } */ > +/* { dg-additional-options "-mavx" { target avx_runtime } } */ > + > +typedef long long V __attribute__((vector_size (16))); > + > +__attribute__((noipa)) V > +foo (V a) > +{ > + return a <= (V) {0, __LONG_LONG_MAX__ }; > +} > + > +int > +main () > +{ > + V t = foo ((V) { 0, 0 }); > + if (t[0] != -1LL || t[1] != -1LL) > + __builtin_abort (); > +} > > Jakub >
--- gcc/config/i386/i386-expand.cc.jj 2024-03-07 08:34:21.043802912 +0100 +++ gcc/config/i386/i386-expand.cc 2024-03-14 22:55:57.321842686 +0100 @@ -4690,7 +4690,7 @@ ix86_expand_int_sse_cmp (rtx dest, enum rtx elt = CONST_VECTOR_ELT (cop1, i); if (!CONST_INT_P (elt)) break; - if (code == GE) + if (code == LE) { /* For LE punt if some element is signed maximum. */ if ((INTVAL (elt) & (GET_MODE_MASK (eltmode) >> 1)) --- gcc/testsuite/gcc.target/i386/pr114339.c.jj 2024-03-14 22:58:04.739076025 +0100 +++ gcc/testsuite/gcc.target/i386/pr114339.c 2024-03-14 22:38:59.736972124 +0100 @@ -0,0 +1,20 @@ +/* PR target/114339 */ +/* { dg-do run } */ +/* { dg-options "-O2 -Wno-psabi" } */ +/* { dg-additional-options "-mavx" { target avx_runtime } } */ + +typedef long long V __attribute__((vector_size (16))); + +__attribute__((noipa)) V +foo (V a) +{ + return a <= (V) {0, __LONG_LONG_MAX__ }; +} + +int +main () +{ + V t = foo ((V) { 0, 0 }); + if (t[0] != -1LL || t[1] != -1LL) + __builtin_abort (); +}
Hi! In r13-3803-gfa271afb58 I've added an optimization for LE/LEU/GE/GEU comparison against CONST_VECTOR. As the comments say: /* x <= cst can be handled as x < cst + 1 unless there is wrap around in cst + 1. */ ... /* For LE punt if some element is signed maximum. */ ... /* For LEU punt if some element is unsigned maximum. */ and /* x >= cst can be handled as x > cst - 1 unless there is wrap around in cst - 1. */ ... /* For GE punt if some element is signed minimum. */ ... /* For GEU punt if some element is zero. */ Apparently I wrote the GE/GEU (second case) first and then copied/adjusted it for LE/LEU, most of the adjustments look correct, but I've left if (code == GE) comparison when testing if it should punt for signed maximum. That condition is never true, because this is in switch (code) { ... case LE: case LEU: block and we really meant to be what the comment says, for LE punt if some element is signed maximum, as then cst + 1 wraps around. The following patch fixes the pasto. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2024-03-15 Jakub Jelinek <jakub@redhat.com> PR target/114339 * config/i386/i386-expand.cc (ix86_expand_int_sse_cmp) <case LE>: Fix a pasto, compare code against LE rather than GE. * gcc.target/i386/pr114339.c: New test. Jakub