[PATCH] move x86 to use gather/scatter internal functions

Richard Biener rguenther@suse.de
Wed Aug 18 09:54:04 GMT 2021


So in the end I seem to be able to combine AVX & AVX512 arriving
at the following which passes basic testing.  I will now see to
teach the vectorizer the required "promotion" to handle
mask_gather_loadv4dfv4si and mask_gather_loadv4sfv4di.

Meanwhile, do you see any hole in the below?  If not I'll
do mask_scatter_store accordingly (that will be simpler since
AVX doesn't have scatter).

Thanks,
Richard.

>From 706d3ac96b384eaad249cc83ec542ec643e21a4c Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Tue, 17 Aug 2021 15:14:38 +0200
Subject: [PATCH] move x86 to use gather/scatter internal functions
To: gcc-patches@gcc.gnu.org

This moves the x86 backend to use standard pattern names for
mask_gather_load and mask_scatter_store rather than using the
builtin_{gather,scatter} target hooks.

The patch starts with mask_gather_load convering AVX and AVX512
and omits gather_load which doesn't match an actual instruction.
The vectorizer will appropriately set up a all-ones mask when
necessary.

The vectorizer still lacks support for unpacking, thus
mixed size gathers like mask_gather_loadv4dfv4si.

2021-08-17  Richard Biener  <rguenther@suse.de>

	* config/i386/sse.md
	(vec_gather_idxsi, vec_gather_idxdi): New lower-case
	mode attributes for VEC_GATHER_IDX{SI,DI}.
	(VEC_GATHER_MODEX): New mode iterator.
	(mask_gather_load<mode><vec_gather_idxsi>): New expander.
	(mask_gather_load<mode><vec_gather_idxdi>): Likewise.
---
 gcc/config/i386/sse.md | 53 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 13889687793..6ae826c268a 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -23640,12 +23640,22 @@
 		       (V2DF "V4SI") (V4DF "V4SI") (V8DF "V8SI")
 		       (V4SI "V4SI") (V8SI "V8SI") (V16SI "V16SI")
 		       (V4SF "V4SI") (V8SF "V8SI") (V16SF "V16SI")])
+(define_mode_attr vec_gather_idxsi
+		      [(V2DI "v4si") (V4DI "v4si") (V8DI "v8si")
+		       (V2DF "v4si") (V4DF "v4si") (V8DF "v8si")
+		       (V4SI "v4si") (V8SI "v8si") (V16SI "v16si")
+		       (V4SF "v4si") (V8SF "v8si") (V16SF "v16si")])
 
 (define_mode_attr VEC_GATHER_IDXDI
 		      [(V2DI "V2DI") (V4DI "V4DI") (V8DI "V8DI")
 		       (V2DF "V2DI") (V4DF "V4DI") (V8DF "V8DI")
 		       (V4SI "V2DI") (V8SI "V4DI") (V16SI "V8DI")
 		       (V4SF "V2DI") (V8SF "V4DI") (V16SF "V8DI")])
+(define_mode_attr vec_gather_idxdi
+		      [(V2DI "v2di") (V4DI "v4di") (V8DI "v8di")
+		       (V2DF "v2di") (V4DF "v4di") (V8DF "v8di")
+		       (V4SI "v2di") (V8SI "v4di") (V16SI "v8di")
+		       (V4SF "v2di") (V8SF "v4di") (V16SF "v8di")])
 
 (define_mode_attr VEC_GATHER_SRCDI
 		      [(V2DI "V2DI") (V4DI "V4DI") (V8DI "V8DI")
@@ -23653,6 +23663,30 @@
 		       (V4SI "V4SI") (V8SI "V4SI") (V16SI "V8SI")
 		       (V4SF "V4SF") (V8SF "V4SF") (V16SF "V8SF")])
 
+(define_mode_iterator VEC_GATHER_MODEX
+  [V2DI V2DF V4DI V4DF V4SI V4SF V8SI V8SF
+   (V8DI "TARGET_AVX512F") (V8DF "TARGET_AVX512F")
+   (V16SI "TARGET_AVX512F") (V16SF "TARGET_AVX512F")])
+
+(define_expand "mask_gather_load<mode><vec_gather_idxsi>"
+  [(match_operand:VEC_GATHER_MODEX 0 "register_operand")
+   (match_operand 1 "vsib_address_operand")
+   (match_operand:<VEC_GATHER_IDXSI> 2 "register_operand")
+   (match_operand:SI 3 "const0_operand")
+   (match_operand:SI 4 "const1248_operand")
+   (match_operand 5 "register_operand")]
+  "TARGET_AVX2 && TARGET_USE_GATHER"
+{
+  rtx scratch = gen_reg_rtx (<MODE>mode);
+  emit_move_insn (scratch, CONST0_RTX(<MODE>mode));
+  if (GET_MODE_SIZE (<MODE>mode) != 32 && !TARGET_AVX512VL)
+    operands[5] = gen_lowpart_SUBREG (<MODE>mode, operands[5]);
+  emit_insn (gen_<avx2_avx512>_gathersi<mode> (operands[0], scratch,
+					       operands[1], operands[2],
+					       operands[5], operands[4]));
+  DONE;
+})
+
 (define_expand "avx2_gathersi<mode>"
   [(parallel [(set (match_operand:VEC_GATHER_MODE 0 "register_operand")
 		   (unspec:VEC_GATHER_MODE
@@ -23714,6 +23748,25 @@
    (set_attr "prefix" "vex")
    (set_attr "mode" "<sseinsnmode>")])
 
+(define_expand "mask_gather_load<mode><vec_gather_idxdi>"
+  [(match_operand:VEC_GATHER_MODEX 0 "register_operand")
+   (match_operand 1 "vsib_address_operand")
+   (match_operand:<VEC_GATHER_IDXDI> 2 "register_operand")
+   (match_operand:SI 3 "const0_operand")
+   (match_operand:SI 4 "const1248_operand")
+   (match_operand 5 "register_operand")]
+  "TARGET_AVX2 && TARGET_USE_GATHER"
+{
+  rtx scratch = gen_reg_rtx (<MODE>mode);
+  emit_move_insn (scratch, CONST0_RTX(<MODE>mode));
+  if (GET_MODE_SIZE (<MODE>mode) != 32 && !TARGET_AVX512VL)
+    operands[5] = gen_lowpart_SUBREG (<VEC_GATHER_SRCDI>mode, operands[5]);
+  emit_insn (gen_<avx2_avx512>_gatherdi<mode> (operands[0], scratch,
+					       operands[1], operands[2],
+					       operands[5], operands[4]));
+  DONE;
+})
+
 (define_expand "avx2_gatherdi<mode>"
   [(parallel [(set (match_operand:VEC_GATHER_MODE 0 "register_operand")
 		   (unspec:VEC_GATHER_MODE
-- 
2.31.1




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