From: Roger Sayle Date: Tue, 5 Jul 2022 17:00:00 +0000 (+0100) Subject: UNSPEC_PALIGNR optimizations and clean-ups on x86. X-Git-Tag: basepoints/gcc-14~5699 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=02e2e15ec4b610c0f5c73e1db424b1bbc65dd39a;p=thirdparty%2Fgcc.git UNSPEC_PALIGNR optimizations and clean-ups on x86. This patch is a follow-up to Hongtao's fix for PR target/105854. That fix is perfectly correct, but the thing that caught my eye was why is the compiler generating a shift by zero at all. Digging deeper it turns out that we can easily optimize __builtin_ia32_palignr for alignments of 0 and 64 respectively, which may be simplified to moves of the highpart and lowpart respectively. After adding optimizations to simplify the 64-bit DImode palignr, I started to add the corresponding optimizations for vpalignr (i.e. 128-bit). The first oddity is that sse.md uses TImode and a special SSESCALARMODE iterator, rather than V1TImode, and indeed the comment above SSESCALARMODE hints that this should be "dropped in favor of VIMAX_AVX2_AVX512BW". Hence this patch includes the migration of _palignr to use VIMAX_AVX2_AVX512BW, basically using V1TImode instead of TImode for 128-bit palignr. This patch has been tested on x86_64-pc-linux-gnu with make bootstrap and make -k check, both with and without --target_board=unix{-,32}, with no new failures. Ok for mainline? 2022-07-05 Roger Sayle Hongtao Liu gcc/ChangeLog * config/i386/i386-builtin.def (__builtin_ia32_palignr128): Change CODE_FOR_ssse3_palignrti to CODE_FOR_ssse3_palignrv1ti. * config/i386/i386-expand.cc (expand_vec_perm_palignr): Use V1TImode and gen_ssse3_palignv1ti instead of TImode. * config/i386/sse.md (SSESCALARMODE): Delete. (define_mode_attr ssse3_avx2): Handle V1TImode instead of TImode. (_palignr): Use VIMAX_AVX2_AVX512BW as a mode iterator instead of SSESCALARMODE. (ssse3_palignrdi): Optimize cases where operands[3] is 0 or 64, using a single move instruction (if required). gcc/testsuite/ChangeLog * gcc.target/i386/ssse3-palignr-2.c: New test case. --- diff --git a/gcc/config/i386/i386-builtin.def b/gcc/config/i386/i386-builtin.def index e6daad47692..fd160935e67 100644 --- a/gcc/config/i386/i386-builtin.def +++ b/gcc/config/i386/i386-builtin.def @@ -900,7 +900,7 @@ BDESC (OPTION_MASK_ISA_SSSE3, 0, CODE_FOR_ssse3_psignv4si3, "__builtin_ia32_psig BDESC (OPTION_MASK_ISA_SSSE3 | OPTION_MASK_ISA_MMX, 0, CODE_FOR_ssse3_psignv2si3, "__builtin_ia32_psignd", IX86_BUILTIN_PSIGND, UNKNOWN, (int) V2SI_FTYPE_V2SI_V2SI) /* SSSE3. */ -BDESC (OPTION_MASK_ISA_SSSE3, 0, CODE_FOR_ssse3_palignrti, "__builtin_ia32_palignr128", IX86_BUILTIN_PALIGNR128, UNKNOWN, (int) V2DI_FTYPE_V2DI_V2DI_INT_CONVERT) +BDESC (OPTION_MASK_ISA_SSSE3, 0, CODE_FOR_ssse3_palignrv1ti, "__builtin_ia32_palignr128", IX86_BUILTIN_PALIGNR128, UNKNOWN, (int) V2DI_FTYPE_V2DI_V2DI_INT_CONVERT) BDESC (OPTION_MASK_ISA_SSSE3 | OPTION_MASK_ISA_MMX, 0, CODE_FOR_ssse3_palignrdi, "__builtin_ia32_palignr", IX86_BUILTIN_PALIGNR, UNKNOWN, (int) V1DI_FTYPE_V1DI_V1DI_INT_CONVERT) /* SSE4.1 */ diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc index 8bc54304da8..6a3fcde5738 100644 --- a/gcc/config/i386/i386-expand.cc +++ b/gcc/config/i386/i386-expand.cc @@ -19548,9 +19548,11 @@ expand_vec_perm_palignr (struct expand_vec_perm_d *d, bool single_insn_only_p) shift = GEN_INT (min * GET_MODE_UNIT_BITSIZE (d->vmode)); if (GET_MODE_SIZE (d->vmode) == 16) { - target = gen_reg_rtx (TImode); - emit_insn (gen_ssse3_palignrti (target, gen_lowpart (TImode, dcopy.op1), - gen_lowpart (TImode, dcopy.op0), shift)); + target = gen_reg_rtx (V1TImode); + emit_insn (gen_ssse3_palignrv1ti (target, + gen_lowpart (V1TImode, dcopy.op1), + gen_lowpart (V1TImode, dcopy.op0), + shift)); } else { diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md index 3396ff748da..81d32a88785 100644 --- a/gcc/config/i386/sse.md +++ b/gcc/config/i386/sse.md @@ -575,10 +575,6 @@ (define_mode_iterator VIMAX_AVX2 [(V2TI "TARGET_AVX2") V1TI]) -;; ??? This should probably be dropped in favor of VIMAX_AVX2_AVX512BW. -(define_mode_iterator SSESCALARMODE - [(V4TI "TARGET_AVX512BW") (V2TI "TARGET_AVX2") TI]) - (define_mode_iterator VI12_AVX2 [(V32QI "TARGET_AVX2") V16QI (V16HI "TARGET_AVX2") V8HI]) @@ -712,7 +708,7 @@ (V4HI "ssse3") (V8HI "ssse3") (V16HI "avx2") (V32HI "avx512bw") (V4SI "ssse3") (V8SI "avx2") (V2DI "ssse3") (V4DI "avx2") - (TI "ssse3") (V2TI "avx2") (V4TI "avx512bw")]) + (V1TI "ssse3") (V2TI "avx2") (V4TI "avx512bw")]) (define_mode_attr sse4_1_avx2 [(V16QI "sse4_1") (V32QI "avx2") (V64QI "avx512bw") @@ -21108,10 +21104,10 @@ (set_attr "mode" "")]) (define_insn "_palignr" - [(set (match_operand:SSESCALARMODE 0 "register_operand" "=x,") - (unspec:SSESCALARMODE - [(match_operand:SSESCALARMODE 1 "register_operand" "0,") - (match_operand:SSESCALARMODE 2 "vector_operand" "xBm,m") + [(set (match_operand:VIMAX_AVX2_AVX512BW 0 "register_operand" "=x,") + (unspec:VIMAX_AVX2_AVX512BW + [(match_operand:VIMAX_AVX2_AVX512BW 1 "register_operand" "0,") + (match_operand:VIMAX_AVX2_AVX512BW 2 "vector_operand" "xBm,m") (match_operand:SI 3 "const_0_to_255_mul_8_operand")] UNSPEC_PALIGNR))] "TARGET_SSSE3" @@ -21157,11 +21153,30 @@ gcc_unreachable (); } } - "TARGET_SSSE3 && reload_completed - && SSE_REGNO_P (REGNO (operands[0]))" + "(TARGET_SSSE3 && reload_completed + && SSE_REGNO_P (REGNO (operands[0]))) + || operands[3] == const0_rtx + || INTVAL (operands[3]) == 64" [(set (match_dup 0) (lshiftrt:V1TI (match_dup 0) (match_dup 3)))] { + if (operands[3] == const0_rtx) + { + if (!rtx_equal_p (operands[0], operands[2])) + emit_move_insn (operands[0], operands[2]); + else + emit_note (NOTE_INSN_DELETED); + DONE; + } + else if (INTVAL (operands[3]) == 64) + { + if (!rtx_equal_p (operands[0], operands[1])) + emit_move_insn (operands[0], operands[1]); + else + emit_note (NOTE_INSN_DELETED); + DONE; + } + /* Emulate MMX palignrdi with SSE psrldq. */ rtx op0 = lowpart_subreg (V2DImode, operands[0], GET_MODE (operands[0])); diff --git a/gcc/testsuite/gcc.target/i386/ssse3-palignr-2.c b/gcc/testsuite/gcc.target/i386/ssse3-palignr-2.c new file mode 100644 index 00000000000..791222ddd78 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/ssse3-palignr-2.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -mssse3" } */ + +typedef long long __attribute__ ((__vector_size__ (8))) T; + +T x; +T y; +T z; + +void foo() +{ + z = __builtin_ia32_palignr (x, y, 0); +} + +void bar() +{ + z = __builtin_ia32_palignr (x, y, 64); +} +/* { dg-final { scan-assembler-not "punpcklqdq" } } */ +/* { dg-final { scan-assembler-not "pshufd" } } */ +/* { dg-final { scan-assembler-not "psrldq" } } */