| Message ID | 20231005231446.400239-1-pinskia@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | MATCH: Fix infinite loop between `vec_cond(vec_cond(a, b, 0), c, d)` and `a & b` | expand |
On Fri, Oct 6, 2023 at 1:15 AM Andrew Pinski <pinskia@gmail.com> wrote:> > Match has a pattern which converts `vec_cond(vec_cond(a,b,0), c, d)` > into `vec_cond(a & b, c, d)` but since in this case a is a comparison > fold will change `a & b` back into `vec_cond(a,b,0)` which causes an > infinite loop. > The best way to fix this is to enable the patterns for vec_cond(*,vec_cond,*) > only for GIMPLE so we don't get an infinite loop for fold any more. > > Note this is a latent bug since these patterns were added in r11-2577-g229752afe3156a > and was exposed by r14-3350-g47b833a9abe1 where now able to remove a VIEW_CONVERT_EXPR. > > OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. OK (also for branches if you like) Richard. > PR middle-end/111699 > > gcc/ChangeLog: > > * match.pd ((c ? a : b) op d, (c ? a : b) op (c ? d : e), > (v ? w : 0) ? a : b, c1 ? c2 ? a : b : b): Enable only for GIMPLE. > > gcc/testsuite/ChangeLog: > > * gcc.c-torture/compile/pr111699-1.c: New test. > --- > gcc/match.pd | 5 +++++ > gcc/testsuite/gcc.c-torture/compile/pr111699-1.c | 7 +++++++ > 2 files changed, 12 insertions(+) > create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr111699-1.c > > diff --git a/gcc/match.pd b/gcc/match.pd > index 4bdd83e6e06..31bfd8b6b68 100644 > --- a/gcc/match.pd > +++ b/gcc/match.pd > @@ -5045,6 +5045,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > /* (v ? w : 0) ? a : b is just (v & w) ? a : b > Currently disabled after pass lvec because ARM understands > VEC_COND_EXPR<v==w,-1,0> but not a plain v==w fed to BIT_IOR_EXPR. */ > +#if GIMPLE > +/* These can only be done in gimple as fold likes to convert: > + (CMP) & N into (CMP) ? N : 0 > + and we try to match the same pattern again and again. */ > (simplify > (vec_cond (vec_cond:s @0 @3 integer_zerop) @1 @2) > (if (optimize_vectors_before_lowering_p () && types_match (@0, @3)) > @@ -5079,6 +5083,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > (vec_cond @0 @3 (vec_cond:s @1 @2 @3)) > (if (optimize_vectors_before_lowering_p () && types_match (@0, @1)) > (vec_cond (bit_and (bit_not @0) @1) @2 @3))) > +#endif > > /* Canonicalize mask ? { 0, ... } : { -1, ...} to ~mask if the mask > types are compatible. */ > diff --git a/gcc/testsuite/gcc.c-torture/compile/pr111699-1.c b/gcc/testsuite/gcc.c-torture/compile/pr111699-1.c > new file mode 100644 > index 00000000000..87b127ed199 > --- /dev/null > +++ b/gcc/testsuite/gcc.c-torture/compile/pr111699-1.c > @@ -0,0 +1,7 @@ > +typedef unsigned char __attribute__((__vector_size__ (8))) V; > + > +void > +foo (V *v) > +{ > + *v = (V) 0x107B9A7FF >= (*v <= 0); > +} > -- > 2.39.3 >
diff --git a/gcc/match.pd b/gcc/match.pd index 4bdd83e6e06..31bfd8b6b68 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -5045,6 +5045,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* (v ? w : 0) ? a : b is just (v & w) ? a : b Currently disabled after pass lvec because ARM understands VEC_COND_EXPR<v==w,-1,0> but not a plain v==w fed to BIT_IOR_EXPR. */ +#if GIMPLE +/* These can only be done in gimple as fold likes to convert: + (CMP) & N into (CMP) ? N : 0 + and we try to match the same pattern again and again. */ (simplify (vec_cond (vec_cond:s @0 @3 integer_zerop) @1 @2) (if (optimize_vectors_before_lowering_p () && types_match (@0, @3)) @@ -5079,6 +5083,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (vec_cond @0 @3 (vec_cond:s @1 @2 @3)) (if (optimize_vectors_before_lowering_p () && types_match (@0, @1)) (vec_cond (bit_and (bit_not @0) @1) @2 @3))) +#endif /* Canonicalize mask ? { 0, ... } : { -1, ...} to ~mask if the mask types are compatible. */ diff --git a/gcc/testsuite/gcc.c-torture/compile/pr111699-1.c b/gcc/testsuite/gcc.c-torture/compile/pr111699-1.c new file mode 100644 index 00000000000..87b127ed199 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/pr111699-1.c @@ -0,0 +1,7 @@ +typedef unsigned char __attribute__((__vector_size__ (8))) V; + +void +foo (V *v) +{ + *v = (V) 0x107B9A7FF >= (*v <= 0); +}