On Sun, Jun 27, 2021 at 1:43 AM Richard Sandiford <richard.sandif...@arm.com> wrote: > > "H.J. Lu" <hjl.to...@gmail.com> writes: > > 1. Update vec_duplicate to allow to fail so that backend can only allow > > broadcasting an integer constant to a vector when broadcast instruction > > is available. This can be used by memset expander to avoid vec_duplicate > > when loading from constant pool is more efficient. > > I don't see any changes in target-independent code though, other than > the doc update. It's still the case that (existing) uses of > vec_duplicate_optab do not allow it to fail.
I have a followup patch set on https://gitlab.com/x86-gcc/gcc/-/commits/users/hjl/pieces/broadcast to use it to expand memset with vector broadcast: https://gitlab.com/x86-gcc/gcc/-/commit/991c87f8a83ca736ae9ed92baa3ebadca289f6e3 For SSE2 which doesn't have vector broadcast, the constant vector broadcast expander returns FAIL and load from constant pool will be used. > Thanks, > Richard > > > 2. Add vec_duplicate<mode> expander and enable vec_duplicate from a > > non-standard SSE constant integer only if vector broadcast is available. > > > > * config/i386/i386-expand.c (ix86_expand_integer_vec_duplicate): > > New function. > > * config/i386/i386-protos.h (ix86_expand_integer_vec_duplicat): > > New prototype. > > * config/i386/sse.md (INT_BROADCAST_MODE): New mode iterator. > > (vec_duplicate<mode>): New expander. > > * doc/md.texi: Update vec_duplicate. > > --- > > gcc/config/i386/i386-expand.c | 24 ++++++++++++++++++++++++ > > gcc/config/i386/i386-protos.h | 1 + > > gcc/config/i386/sse.md | 28 ++++++++++++++++++++++++++++ > > gcc/doc/md.texi | 2 -- > > 4 files changed, 53 insertions(+), 2 deletions(-) > > > > diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c > > index e9e89c82764..75c160d4349 100644 > > --- a/gcc/config/i386/i386-expand.c > > +++ b/gcc/config/i386/i386-expand.c > > @@ -15742,6 +15742,30 @@ ix86_expand_vector_extract (bool mmx_ok, rtx > > target, rtx vec, int elt) > > } > > } > > > > +/* Expand integer vec_duplicate. Return true if successful. */ > > + > > +bool > > +ix86_expand_integer_vec_duplicate (rtx *operands) > > +{ > > + /* Enable VEC_DUPLICATE from a non-standard SSE constant integer only > > + if vector broadcast is available. */ > > + machine_mode mode = GET_MODE (operands[0]); > > + if (CONST_INT_P (operands[1]) > > + && (!(TARGET_AVX2 > > + || (TARGET_AVX > > + && (GET_MODE_INNER (mode) == SImode > > + || GET_MODE_INNER (mode) == DImode))) > > + || standard_sse_constant_p (operands[1], mode))) > > + return false; > > + > > + bool ok = ix86_expand_vector_init_duplicate (false, mode, > > + operands[0], > > + operands[1]); > > + gcc_assert (ok); > > + > > + return true; > > +} > > + > > /* Generate code to copy vector bits i / 2 ... i - 1 from vector SRC > > to bits 0 ... i / 2 - 1 of vector DEST, which has the same mode. > > The upper bits of DEST are undefined, though they shouldn't cause > > diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h > > index 71745b9a1ea..a6cc09bb75b 100644 > > --- a/gcc/config/i386/i386-protos.h > > +++ b/gcc/config/i386/i386-protos.h > > @@ -258,6 +258,7 @@ extern void ix86_expand_mul_widen_hilo (rtx, rtx, rtx, > > bool, bool); > > extern void ix86_expand_sse2_mulv4si3 (rtx, rtx, rtx); > > extern void ix86_expand_sse2_mulvxdi3 (rtx, rtx, rtx); > > extern void ix86_expand_sse2_abs (rtx, rtx); > > +extern bool ix86_expand_integer_vec_duplicate (rtx *); > > > > /* In i386-c.c */ > > extern void ix86_target_macros (void); > > diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md > > index e4f01e64bc1..53a703fb466 100644 > > --- a/gcc/config/i386/sse.md > > +++ b/gcc/config/i386/sse.md > > @@ -24640,3 +24640,31 @@ (define_insn "*aes<aeswideklvariant>u8" > > "TARGET_WIDEKL" > > "aes<aeswideklvariant>\t{%0}" > > [(set_attr "type" "other")]) > > + > > +;; Modes handled by broadcast patterns. NB: Allow V64QI and V32HI with > > +;; TARGET_AVX512F since ix86_expand_integer_vec_duplicate can expand > > +;; without TARGET_AVX512BW which is used by memset vector broadcast > > +;; expander to XI with: > > +;; vmovd %edi, %xmm15 > > +;; vpbroadcastb %xmm15, %ymm15 > > +;; vinserti64x4 $0x1, %ymm15, %zmm15, %zmm15 > > + > > +(define_mode_iterator INT_BROADCAST_MODE > > + [(V64QI "TARGET_AVX512F") (V32QI "TARGET_AVX") V16QI > > + (V32HI "TARGET_AVX512F") (V16HI "TARGET_AVX") V8HI > > + (V16SI "TARGET_AVX512F") (V8SI "TARGET_AVX") V4SI > > + (V8DI "TARGET_AVX512F && TARGET_64BIT") > > + (V4DI "TARGET_AVX && TARGET_64BIT") (V2DI "TARGET_64BIT")]) > > + > > +;; Broadcast from an integer. NB: Enable broadcast only if we can move > > +;; from GPR to SSE register directly. > > +(define_expand "vec_duplicate<mode>" > > + [(set (match_operand:INT_BROADCAST_MODE 0 "register_operand") > > + (vec_duplicate:INT_BROADCAST_MODE > > + (match_operand:<ssescalarmode> 1 "general_operand")))] > > + "TARGET_SSE2 && TARGET_INTER_UNIT_MOVES_TO_VEC" > > +{ > > + if (!ix86_expand_integer_vec_duplicate (operands)) > > + FAIL; > > + DONE; > > +}) > > diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi > > index 1b918144330..a892c94d163 100644 > > --- a/gcc/doc/md.texi > > +++ b/gcc/doc/md.texi > > @@ -5077,8 +5077,6 @@ the mode appropriate for one element of @var{m}. > > This pattern only handles duplicates of non-constant inputs. Constant > > vectors go through the @code{mov@var{m}} pattern instead. > > > > -This pattern is not allowed to @code{FAIL}. > > - > > @cindex @code{vec_series@var{m}} instruction pattern > > @item @samp{vec_series@var{m}} > > Initialize vector output operand 0 so that element @var{i} is equal to -- H.J.