Hi!
As mentioned in the PR, we can use psadbw to shorten the final reductions to
scalar for 8-bit elements. E.g. for -mavx2 the difference is:
- vmovdqa %xmm1, %xmm0
- vextracti128 $0x1, %ymm1, %xmm1
- vpaddb %xmm1, %xmm0, %xmm0
- vpsrldq $8, %xmm0, %xmm1
- vpaddb %xmm1, %xmm0, %xmm0
- vpsrldq $4, %xmm0, %xmm1
- vpaddb %xmm1, %xmm0, %xmm0
- vpsrldq $2, %xmm0, %xmm1
- vpaddb %xmm1, %xmm0, %xmm0
- vpsrldq $1, %xmm0, %xmm1
- vpaddb %xmm1, %xmm0, %xmm0
+ vextracti128 $0x1, %ymm1, %xmm0
+ vpaddb %xmm1, %xmm0, %xmm1
+ vpsrldq $8, %xmm1, %xmm0
+ vpaddb %xmm0, %xmm1, %xmm1
+ vpxor %xmm0, %xmm0, %xmm0
+ vpsadbw %xmm0, %xmm1, %xmm0
vpextrb $0, %xmm0, %eax
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2019-07-31 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/91201
* config/i386/sse.md (reduc_plus_scal_v16qi): New expander.
(REDUC_PLUS_MODE): Add V32QImode for TARGET_AVX and V64QImode for
TARGET_AVX512F.
(reduc_plus_scal_<mode>): Improve formatting by introducing
a temporary.
* gcc.target/i386/sse2-pr91201.c: New test.
* gcc.target/i386/avx2-pr91201.c: New test.
* gcc.target/i386/avx512bw-pr91201.c: New test.
--- gcc/config/i386/sse.md.jj 2019-07-30 12:19:45.999490854 +0200
+++ gcc/config/i386/sse.md 2019-07-30 12:19:55.379352735 +0200
@@ -2728,9 +2728,30 @@ (define_expand "reduc_plus_scal_<mode>"
DONE;
})
+(define_expand "reduc_plus_scal_v16qi"
+ [(plus:V16QI
+ (match_operand:QI 0 "register_operand")
+ (match_operand:V16QI 1 "register_operand"))]
+ "TARGET_SSE2"
+{
+ rtx tmp = gen_reg_rtx (V1TImode);
+ emit_insn (gen_sse2_lshrv1ti3 (tmp, gen_lowpart (V1TImode, operands[1]),
+ GEN_INT (64)));
+ rtx tmp2 = gen_reg_rtx (V16QImode);
+ emit_insn (gen_addv16qi3 (tmp2, operands[1], gen_lowpart (V16QImode, tmp)));
+ rtx tmp3 = gen_reg_rtx (V16QImode);
+ emit_move_insn (tmp3, CONST0_RTX (V16QImode));
+ rtx tmp4 = gen_reg_rtx (V2DImode);
+ emit_insn (gen_sse2_psadbw (tmp4, tmp2, tmp3));
+ tmp4 = gen_lowpart (V16QImode, tmp4);
+ emit_insn (gen_vec_extractv16qiqi (operands[0], tmp4, const0_rtx));
+ DONE;
+})
+
(define_mode_iterator REDUC_PLUS_MODE
[(V4DF "TARGET_AVX") (V8SF "TARGET_AVX")
- (V8DF "TARGET_AVX512F") (V16SF "TARGET_AVX512F")])
+ (V8DF "TARGET_AVX512F") (V16SF "TARGET_AVX512F")
+ (V32QI "TARGET_AVX") (V64QI "TARGET_AVX512F")])
(define_expand "reduc_plus_scal_<mode>"
[(plus:REDUC_PLUS_MODE
@@ -2741,8 +2762,8 @@ (define_expand "reduc_plus_scal_<mode>"
rtx tmp = gen_reg_rtx (<ssehalfvecmode>mode);
emit_insn (gen_vec_extract_hi_<mode> (tmp, operands[1]));
rtx tmp2 = gen_reg_rtx (<ssehalfvecmode>mode);
- emit_insn (gen_add<ssehalfvecmodelower>3
- (tmp2, tmp, gen_lowpart (<ssehalfvecmode>mode, operands[1])));
+ rtx tmp3 = gen_lowpart (<ssehalfvecmode>mode, operands[1]);
+ emit_insn (gen_add<ssehalfvecmodelower>3 (tmp2, tmp, tmp3));
emit_insn (gen_reduc_plus_scal_<ssehalfvecmodelower> (operands[0], tmp2));
DONE;
})
--- gcc/testsuite/gcc.target/i386/sse2-pr91201.c.jj 2019-07-30
12:23:48.930913778 +0200
+++ gcc/testsuite/gcc.target/i386/sse2-pr91201.c 2019-07-30
12:23:45.518964018 +0200
@@ -0,0 +1,18 @@
+/* PR tree-optimization/91201 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -msse2 -mno-sse3" } */
+/* { dg-final { scan-assembler "\tpsadbw\t" } } */
+
+unsigned char bytes[1024];
+
+unsigned char
+sum (void)
+{
+ unsigned char r = 0;
+ unsigned char *p = (unsigned char *) bytes;
+ int n;
+
+ for (n = 0; n < sizeof (bytes); ++n)
+ r += p[n];
+ return r;
+}
--- gcc/testsuite/gcc.target/i386/avx2-pr91201.c.jj 2019-07-30
12:24:05.199674228 +0200
+++ gcc/testsuite/gcc.target/i386/avx2-pr91201.c 2019-07-30
12:24:34.544242142 +0200
@@ -0,0 +1,6 @@
+/* PR tree-optimization/91201 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -mavx2 -mno-avx512f" } */
+/* { dg-final { scan-assembler "\tvpsadbw\t" } } */
+
+#include "sse2-pr91201.c"
--- gcc/testsuite/gcc.target/i386/avx512bw-pr91201.c.jj 2019-07-30
12:24:50.079013395 +0200
+++ gcc/testsuite/gcc.target/i386/avx512bw-pr91201.c 2019-07-30
12:25:10.685709971 +0200
@@ -0,0 +1,6 @@
+/* PR tree-optimization/91201 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -mavx512bw -mprefer-vector-width=512" } */
+/* { dg-final { scan-assembler "\tvpsadbw\t" } } */
+
+#include "sse2-pr91201.c"
Jakub
