Message ID | 032301d835a2$86214110$9263c330$@nextmovesoftware.com |
---|---|
State | New |
Headers | show |
Series | PR tree-optimization/101895: Fold VEC_PERM to help recognize FMA. | expand |
On Fri, 11 Mar 2022, Roger Sayle wrote: +(match vec_same_elem_p + CONSTRUCTOR@0 + (if (uniform_vector_p (TREE_CODE (@0) == SSA_NAME + ? gimple_assign_rhs1 (SSA_NAME_DEF_STMT (@0)) : @0)))) Ah, I didn't remember we needed that, we don't seem to be very consistent about it. Probably for this reason, the transformation "Prefer vector1 << scalar to vector1 << vector2" does not match typedef int vec __attribute__((vector_size(16))); vec f(vec a, int b){ vec bb = { b, b, b, b }; return a << bb; } which is only optimized at vector lowering time. +/* Push VEC_PERM earlier if that may help FMA perception (PR101895). */ +(for plusminus (plus minus) + (simplify + (plusminus (vec_perm (mult@0 @1 vec_same_elem_p@2) @0 @3) @4) + (plusminus (mult (vec_perm @1 @1 @3) @2) @4))) Don't you want :s on mult and vec_perm?
On Sun, Mar 13, 2022 at 12:39 AM Marc Glisse via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > On Fri, 11 Mar 2022, Roger Sayle wrote: > > +(match vec_same_elem_p > + CONSTRUCTOR@0 > + (if (uniform_vector_p (TREE_CODE (@0) == SSA_NAME > + ? gimple_assign_rhs1 (SSA_NAME_DEF_STMT (@0)) : @0)))) > > Ah, I didn't remember we needed that, we don't seem to be very consistent > about it. Probably for this reason, the transformation "Prefer vector1 << > scalar to vector1 << vector2" does not match > > typedef int vec __attribute__((vector_size(16))); > vec f(vec a, int b){ > vec bb = { b, b, b, b }; > return a << bb; > } > > which is only optimized at vector lowering time. Few more comments - since match.pd is matching in match.pd order the (match vec_same_elem_p @0 (...)) should come last. Please use +(match vec_same_elem_p + CONSTRUCTOR@0 (if (TREE_CODE (@0) == SSA_NAME && uniform_vector_p (... since otherwise we'll try uniform_vector_p twice on all CTORs (that are not uniform). > +/* Push VEC_PERM earlier if that may help FMA perception (PR101895). */ > +(for plusminus (plus minus) > + (simplify > + (plusminus (vec_perm (mult@0 @1 vec_same_elem_p@2) @0 @3) @4) > + (plusminus (mult (vec_perm @1 @1 @3) @2) @4))) > > Don't you want :s on mult and vec_perm? Yes. Also for plus you want :c on it , likewise you want :c on the mult. The :c on the plus will require splitting the plus and minus case :/ Otherwise looks reasonable. Richard. > > -- > Marc Glisse
Hi Richard and Marc, Many thanks for both your feedback on my patch for PR 101895. Here's version 2 of this patch, incorporating all of the suggested improvements. The one minor complication is that the :s qualifier doesn't automatically recognize that a capture already has two (or N) uses in a pattern, so I have to manually confirm that there are no other uses of the mult using num_imm_uses. This revision has been tested on x86_64-pc-linux-gnu with make bootstrap and make -k check with no new failures. Ok for mainline? 2022-03-15 Roger Sayle <roger@nextmovesoftware.com> Marc Glisse <marc.glisse@inria.fr> Richard Biener <rguenther@suse.de> gcc/ChangeLog PR tree-optimization/101895 * match.pd (vec_same_elem_p): Handle CONSTRUCTOR_EXPR def. (plus (vec_perm (mult ...) ...) ...): New reordering simplification. gcc/testsuite/ChangeLog PR tree-optimization/101895 * gcc.target/i386/pr101895.c: New test case. Thanks in advance, Roger -- > -----Original Message----- > From: Richard Biener <richard.guenther@gmail.com> > Sent: 14 March 2022 07:38 > To: GCC Patches <gcc-patches@gcc.gnu.org> > Cc: Roger Sayle <roger@nextmovesoftware.com>; Marc Glisse > <marc.glisse@inria.fr> > Subject: Re: [PATCH] PR tree-optimization/101895: Fold VEC_PERM to help > recognize FMA. > > On Sun, Mar 13, 2022 at 12:39 AM Marc Glisse via Gcc-patches <gcc- > patches@gcc.gnu.org> wrote: > > > > On Fri, 11 Mar 2022, Roger Sayle wrote: > > > > +(match vec_same_elem_p > > + CONSTRUCTOR@0 > > + (if (uniform_vector_p (TREE_CODE (@0) == SSA_NAME > > + ? gimple_assign_rhs1 (SSA_NAME_DEF_STMT (@0)) > > +: @0)))) > > > > Ah, I didn't remember we needed that, we don't seem to be very > > consistent about it. Probably for this reason, the transformation > > "Prefer vector1 << scalar to vector1 << vector2" does not match > > > > typedef int vec __attribute__((vector_size(16))); vec f(vec a, int b){ > > vec bb = { b, b, b, b }; > > return a << bb; > > } > > > > which is only optimized at vector lowering time. > > Few more comments - since match.pd is matching in match.pd order the > > (match vec_same_elem_p > @0 > (...)) > > should come last. Please use > > +(match vec_same_elem_p > + CONSTRUCTOR@0 > (if (TREE_CODE (@0) == SSA_NAME > && uniform_vector_p (... > > since otherwise we'll try uniform_vector_p twice on all CTORs (that are not > uniform). > > > +/* Push VEC_PERM earlier if that may help FMA perception (PR101895). > > +*/ (for plusminus (plus minus) > > + (simplify > > + (plusminus (vec_perm (mult@0 @1 vec_same_elem_p@2) @0 @3) @4) > > + (plusminus (mult (vec_perm @1 @1 @3) @2) @4))) > > > > Don't you want :s on mult and vec_perm? > > Yes. Also for plus you want :c on it , likewise you want :c on the mult. The :c on > the plus will require splitting the plus and minus case :/ > > Otherwise looks reasonable. > > Richard. > > > > > -- > > Marc Glisse diff --git a/gcc/match.pd b/gcc/match.pd index 97399e5..12c92f4 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -7689,16 +7689,33 @@ and, /* VEC_PERM_EXPR (v, v, mask) -> v where v contains same element. */ (match vec_same_elem_p + (vec_duplicate @0)) + +(match vec_same_elem_p + CONSTRUCTOR@0 + (if (TREE_CODE (@0) == SSA_NAME + && uniform_vector_p (gimple_assign_rhs1 (SSA_NAME_DEF_STMT (@0)))))) + +(match vec_same_elem_p @0 (if (uniform_vector_p (@0)))) -(match vec_same_elem_p - (vec_duplicate @0)) (simplify (vec_perm vec_same_elem_p@0 @0 @1) @0) +/* Push VEC_PERM earlier if that may help FMA perception (PR101895). */ +(simplify + (plus:c (vec_perm:s (mult:c@0 @1 vec_same_elem_p@2) @0 @3) @4) + (if (TREE_CODE (@0) == SSA_NAME && num_imm_uses (@0) == 2) + (plus (mult (vec_perm @1 @1 @3) @2) @4))) +(simplify + (minus (vec_perm:s (mult:c@0 @1 vec_same_elem_p@2) @0 @3) @4) + (if (TREE_CODE (@0) == SSA_NAME && num_imm_uses (@0) == 2) + (minus (mult (vec_perm @1 @1 @3) @2) @4))) + + /* Match count trailing zeroes for simplify_count_trailing_zeroes in fwprop. The canonical form is array[((x & -x) * C) >> SHIFT] where C is a magic constant which when multiplied by a power of 2 contains a unique value diff --git a/gcc/testsuite/gcc.target/i386/pr101895.c b/gcc/testsuite/gcc.target/i386/pr101895.c new file mode 100644 index 0000000..4d0f1cb --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr101895.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -march=cascadelake" } */ + +void foo(float * __restrict__ a, float b, float *c) { + a[0] = c[0]*b + a[0]; + a[1] = c[2]*b + a[1]; + a[2] = c[1]*b + a[2]; + a[3] = c[3]*b + a[3]; +} + +/* { dg-final { scan-assembler "vfmadd" } } */
On Tue, Mar 15, 2022 at 8:25 AM Roger Sayle <roger@nextmovesoftware.com> wrote: > > > Hi Richard and Marc, > Many thanks for both your feedback on my patch for PR 101895. > Here's version 2 of this patch, incorporating all of the suggested improvements. > The one minor complication is that the :s qualifier doesn't automatically > recognize that a capture already has two (or N) uses in a pattern, > so I have to manually confirm that there are no other uses of the mult > using num_imm_uses. > > This revision has been tested on x86_64-pc-linux-gnu with make bootstrap > and make -k check with no new failures. Ok for mainline? OK. Thanks, Richard. > 2022-03-15 Roger Sayle <roger@nextmovesoftware.com> > Marc Glisse <marc.glisse@inria.fr> > Richard Biener <rguenther@suse.de> > > gcc/ChangeLog > PR tree-optimization/101895 > * match.pd (vec_same_elem_p): Handle CONSTRUCTOR_EXPR def. > (plus (vec_perm (mult ...) ...) ...): New reordering simplification. > > gcc/testsuite/ChangeLog > PR tree-optimization/101895 > * gcc.target/i386/pr101895.c: New test case. > > > Thanks in advance, > Roger > -- > > > -----Original Message----- > > From: Richard Biener <richard.guenther@gmail.com> > > Sent: 14 March 2022 07:38 > > To: GCC Patches <gcc-patches@gcc.gnu.org> > > Cc: Roger Sayle <roger@nextmovesoftware.com>; Marc Glisse > > <marc.glisse@inria.fr> > > Subject: Re: [PATCH] PR tree-optimization/101895: Fold VEC_PERM to help > > recognize FMA. > > > > On Sun, Mar 13, 2022 at 12:39 AM Marc Glisse via Gcc-patches <gcc- > > patches@gcc.gnu.org> wrote: > > > > > > On Fri, 11 Mar 2022, Roger Sayle wrote: > > > > > > +(match vec_same_elem_p > > > + CONSTRUCTOR@0 > > > + (if (uniform_vector_p (TREE_CODE (@0) == SSA_NAME > > > + ? gimple_assign_rhs1 (SSA_NAME_DEF_STMT (@0)) > > > +: @0)))) > > > > > > Ah, I didn't remember we needed that, we don't seem to be very > > > consistent about it. Probably for this reason, the transformation > > > "Prefer vector1 << scalar to vector1 << vector2" does not match > > > > > > typedef int vec __attribute__((vector_size(16))); vec f(vec a, int b){ > > > vec bb = { b, b, b, b }; > > > return a << bb; > > > } > > > > > > which is only optimized at vector lowering time. > > > > Few more comments - since match.pd is matching in match.pd order the > > > > (match vec_same_elem_p > > @0 > > (...)) > > > > should come last. Please use > > > > +(match vec_same_elem_p > > + CONSTRUCTOR@0 > > (if (TREE_CODE (@0) == SSA_NAME > > && uniform_vector_p (... > > > > since otherwise we'll try uniform_vector_p twice on all CTORs (that are not > > uniform). > > > > > +/* Push VEC_PERM earlier if that may help FMA perception (PR101895). > > > +*/ (for plusminus (plus minus) > > > + (simplify > > > + (plusminus (vec_perm (mult@0 @1 vec_same_elem_p@2) @0 @3) @4) > > > + (plusminus (mult (vec_perm @1 @1 @3) @2) @4))) > > > > > > Don't you want :s on mult and vec_perm? > > > > Yes. Also for plus you want :c on it , likewise you want :c on the mult. The :c on > > the plus will require splitting the plus and minus case :/ > > > > Otherwise looks reasonable. > > > > Richard. > > > > > > > > -- > > > Marc Glisse
diff --git a/gcc/match.pd b/gcc/match.pd index 97399e5..9184276 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -7695,10 +7695,22 @@ and, (match vec_same_elem_p (vec_duplicate @0)) +(match vec_same_elem_p + CONSTRUCTOR@0 + (if (uniform_vector_p (TREE_CODE (@0) == SSA_NAME + ? gimple_assign_rhs1 (SSA_NAME_DEF_STMT (@0)) : @0)))) + (simplify (vec_perm vec_same_elem_p@0 @0 @1) @0) +/* Push VEC_PERM earlier if that may help FMA perception (PR101895). */ +(for plusminus (plus minus) + (simplify + (plusminus (vec_perm (mult@0 @1 vec_same_elem_p@2) @0 @3) @4) + (plusminus (mult (vec_perm @1 @1 @3) @2) @4))) + + /* Match count trailing zeroes for simplify_count_trailing_zeroes in fwprop. The canonical form is array[((x & -x) * C) >> SHIFT] where C is a magic constant which when multiplied by a power of 2 contains a unique value diff --git a/gcc/testsuite/gcc.target/i386/pr101895.c b/gcc/testsuite/gcc.target/i386/pr101895.c new file mode 100644 index 0000000..4d0f1cb --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr101895.c @@ -0,0 +1,11 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -march=cascadelake" } */ + +void foo(float * __restrict__ a, float b, float *c) { + a[0] = c[0]*b + a[0]; + a[1] = c[2]*b + a[1]; + a[2] = c[1]*b + a[2]; + a[3] = c[3]*b + a[3]; +} + +/* { dg-final { scan-assembler "vfmadd" } } */