[gcc(refs/users/meissner/heads/work255-sha)] PR target/117251: Improve vector fusion #7
Michael Meissner via Gcc-cvs <[email protected]> Mon, 3 Aug 2026 19:54:02 +0000 (GMT)
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https://gcc.gnu.org/g:2cff5c0813b8563a03250427e89a3c6279c143e8 commit 2cff5c0813b8563a03250427e89a3c6279c143e8 Author: Michael Meissner <[email protected]> Date: Mon Aug 3 15:52:32 2026 -0400 PR target/117251: Improve vector fusion #7 See the following post for a complete explanation of what the patches for PR target/117251: * https://gcc.gnu.org/pipermail/gcc-patches/2025-June/686474.html This is patch #2 of 45 to generate the 'XXEVAL' instruction on power10 and power11 instead of using the Altivec 'VANDC' instruction feeding into 'VAND'. The 'XXEVAL' instruction can use all 64 vector registers, instead of the 32 registers that traditional Altivec vector instructions use. By allowing all of the vector registers to be used, it reduces the amount of spilling that a large benchmark generated. For vectors such as: vector int a, b, c, d; This patch will generate a call to xxeval if any of the registers are allocated to traditional floating point registers: Code: Old: New: ===== ==== ==== a = ~ ((~ (c | d)) & b); vnor t,c,d xxeval a,b,c,d,247 vnand a,t,b a = ~ ((c | d) & b); vor t,c,d xxeval a,b,c,d,248 vnand a,t,b a = ~ ((c ^ d) & b); vxor t,c,d xxeval a,b,c,d,249 vnand a,t,b a = ~ ((c & ~ d) & b); vandc t,c,d xxeval a,b,c,d,253 vnand a,t,b a = ~ ((c & d) & b); vand t,c,d xxeval a,b,c,d,254 vnand a,t,b Since fusion using 2 Altivec instructions is slightly faster than using the 'XXEVAL' instruction we prefer to generate the Altivec instructions if we can. In addition, because 'XXEVAL' is a prefixed instruction, it possibly might generate an extra NOP instruction to align the 'XXEVAL' instruction. I have tested these patches on both big endian and little endian PowerPC servers, with no regressions. Can I check these patches into the trunk? I have committed all of the patches in my backlog (dense math registers, other -mcpu=future instructions, random bug fixes, support for _Float16 and __bfloat16, and optimizations for vector logical operations on power10/power11) into the IBM vendor branch: vendors/ibm/gcc-17-future 2026-08-03 Michael Meissner <[email protected]> gcc/ PR target/117251 * config/rs6000/fusion.md: Regenerate. * config/rs6000/genfusion.pl (gen_logical_addsubf): Add support to generate vector/vector fusion if XXEVAL is supported. Diff: --- gcc/config/rs6000/fusion.md | 75 +++++++++++++++++++++++++----------------- gcc/config/rs6000/genfusion.pl | 5 +++ 2 files changed, 50 insertions(+), 30 deletions(-) diff --git a/gcc/config/rs6000/fusion.md b/gcc/config/rs6000/fusion.md index 14e00f44271a..d433629c3a0c 100644 --- a/gcc/config/rs6000/fusion.md +++ b/gcc/config/rs6000/fusion.md @@ -2336,38 +2336,44 @@ ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector vand -> vnand (define_insn "*fuse_vand_vnand" - [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v") - (ior:VM (not:VM (and:VM (match_operand:VM 0 "altivec_register_operand" "v,v,v,v") - (match_operand:VM 1 "altivec_register_operand" "v,v,v,v"))) - (not:VM (match_operand:VM 2 "altivec_register_operand" "v,v,v,v")))) - (clobber (match_scratch:VM 4 "=X,X,X,&v"))] + [(set (match_operand:VM 3 "vector_fusion_operand" "=&0,&1,&v,wa,v") + (ior:VM (not:VM (and:VM (match_operand:VM 0 "vector_fusion_operand" "v,v,v,wa,v") + (match_operand:VM 1 "vector_fusion_operand" "v,v,v,wa,v"))) + (not:VM (match_operand:VM 2 "vector_fusion_operand" "v,v,v,wa,v")))) + (clobber (match_scratch:VM 4 "=X,X,X,X,&v"))] "(TARGET_P10_FUSION)" "@ vand %3,%1,%0\;vnand %3,%3,%2 vand %3,%1,%0\;vnand %3,%3,%2 vand %3,%1,%0\;vnand %3,%3,%2 + xxeval %x3,%x2,%x1,%x0,254 vand %4,%1,%0\;vnand %3,%4,%2" [(set_attr "type" "fused_vector") (set_attr "cost" "6") - (set_attr "length" "8")]) + (set_attr "length" "8") + (set_attr "prefixed" "*,*,*,yes,*") + (set_attr "isa" "*,*,*,p10p,*")]) ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector vandc -> vnand (define_insn "*fuse_vandc_vnand" - [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v") - (ior:VM (not:VM (and:VM (not:VM (match_operand:VM 0 "altivec_register_operand" "v,v,v,v")) - (match_operand:VM 1 "altivec_register_operand" "v,v,v,v"))) - (not:VM (match_operand:VM 2 "altivec_register_operand" "v,v,v,v")))) - (clobber (match_scratch:VM 4 "=X,X,X,&v"))] + [(set (match_operand:VM 3 "vector_fusion_operand" "=&0,&1,&v,wa,v") + (ior:VM (not:VM (and:VM (not:VM (match_operand:VM 0 "vector_fusion_operand" "v,v,v,wa,v")) + (match_operand:VM 1 "vector_fusion_operand" "v,v,v,wa,v"))) + (not:VM (match_operand:VM 2 "vector_fusion_operand" "v,v,v,wa,v")))) + (clobber (match_scratch:VM 4 "=X,X,X,X,&v"))] "(TARGET_P10_FUSION)" "@ vandc %3,%1,%0\;vnand %3,%3,%2 vandc %3,%1,%0\;vnand %3,%3,%2 vandc %3,%1,%0\;vnand %3,%3,%2 + xxeval %x3,%x2,%x1,%x0,253 vandc %4,%1,%0\;vnand %3,%4,%2" [(set_attr "type" "fused_vector") (set_attr "cost" "6") - (set_attr "length" "8")]) + (set_attr "length" "8") + (set_attr "prefixed" "*,*,*,yes,*") + (set_attr "isa" "*,*,*,p10p,*")]) ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector veqv -> vnand @@ -2414,38 +2420,44 @@ ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector vnor -> vnand (define_insn "*fuse_vnor_vnand" - [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v") - (ior:VM (not:VM (and:VM (not:VM (match_operand:VM 0 "altivec_register_operand" "v,v,v,v")) - (not:VM (match_operand:VM 1 "altivec_register_operand" "v,v,v,v")))) - (not:VM (match_operand:VM 2 "altivec_register_operand" "v,v,v,v")))) - (clobber (match_scratch:VM 4 "=X,X,X,&v"))] + [(set (match_operand:VM 3 "vector_fusion_operand" "=&0,&1,&v,wa,v") + (ior:VM (not:VM (and:VM (not:VM (match_operand:VM 0 "vector_fusion_operand" "v,v,v,wa,v")) + (not:VM (match_operand:VM 1 "vector_fusion_operand" "v,v,v,wa,v")))) + (not:VM (match_operand:VM 2 "vector_fusion_operand" "v,v,v,wa,v")))) + (clobber (match_scratch:VM 4 "=X,X,X,X,&v"))] "(TARGET_P10_FUSION)" "@ vnor %3,%1,%0\;vnand %3,%3,%2 vnor %3,%1,%0\;vnand %3,%3,%2 vnor %3,%1,%0\;vnand %3,%3,%2 + xxeval %x3,%x2,%x1,%x0,247 vnor %4,%1,%0\;vnand %3,%4,%2" [(set_attr "type" "fused_vector") (set_attr "cost" "6") - (set_attr "length" "8")]) + (set_attr "length" "8") + (set_attr "prefixed" "*,*,*,yes,*") + (set_attr "isa" "*,*,*,p10p,*")]) ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector vor -> vnand (define_insn "*fuse_vor_vnand" - [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v") - (ior:VM (not:VM (ior:VM (match_operand:VM 0 "altivec_register_operand" "v,v,v,v") - (match_operand:VM 1 "altivec_register_operand" "v,v,v,v"))) - (not:VM (match_operand:VM 2 "altivec_register_operand" "v,v,v,v")))) - (clobber (match_scratch:VM 4 "=X,X,X,&v"))] + [(set (match_operand:VM 3 "vector_fusion_operand" "=&0,&1,&v,wa,v") + (ior:VM (not:VM (ior:VM (match_operand:VM 0 "vector_fusion_operand" "v,v,v,wa,v") + (match_operand:VM 1 "vector_fusion_operand" "v,v,v,wa,v"))) + (not:VM (match_operand:VM 2 "vector_fusion_operand" "v,v,v,wa,v")))) + (clobber (match_scratch:VM 4 "=X,X,X,X,&v"))] "(TARGET_P10_FUSION)" "@ vor %3,%1,%0\;vnand %3,%3,%2 vor %3,%1,%0\;vnand %3,%3,%2 vor %3,%1,%0\;vnand %3,%3,%2 + xxeval %x3,%x2,%x1,%x0,248 vor %4,%1,%0\;vnand %3,%4,%2" [(set_attr "type" "fused_vector") (set_attr "cost" "6") - (set_attr "length" "8")]) + (set_attr "length" "8") + (set_attr "prefixed" "*,*,*,yes,*") + (set_attr "isa" "*,*,*,p10p,*")]) ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector vorc -> vnand @@ -2471,20 +2483,23 @@ ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector vxor -> vnand (define_insn "*fuse_vxor_vnand" - [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v") - (ior:VM (not:VM (xor:VM (match_operand:VM 0 "altivec_register_operand" "v,v,v,v") - (match_operand:VM 1 "altivec_register_operand" "v,v,v,v"))) - (not:VM (match_operand:VM 2 "altivec_register_operand" "v,v,v,v")))) - (clobber (match_scratch:VM 4 "=X,X,X,&v"))] + [(set (match_operand:VM 3 "vector_fusion_operand" "=&0,&1,&v,wa,v") + (ior:VM (not:VM (xor:VM (match_operand:VM 0 "vector_fusion_operand" "v,v,v,wa,v") + (match_operand:VM 1 "vector_fusion_operand" "v,v,v,wa,v"))) + (not:VM (match_operand:VM 2 "vector_fusion_operand" "v,v,v,wa,v")))) + (clobber (match_scratch:VM 4 "=X,X,X,X,&v"))] "(TARGET_P10_FUSION)" "@ vxor %3,%1,%0\;vnand %3,%3,%2 vxor %3,%1,%0\;vnand %3,%3,%2 vxor %3,%1,%0\;vnand %3,%3,%2 + xxeval %x3,%x2,%x1,%x0,249 vxor %4,%1,%0\;vnand %3,%4,%2" [(set_attr "type" "fused_vector") (set_attr "cost" "6") - (set_attr "length" "8")]) + (set_attr "length" "8") + (set_attr "prefixed" "*,*,*,yes,*") + (set_attr "isa" "*,*,*,p10p,*")]) ;; logical-logical fusion pattern generated by gen_logical_addsubf ;; vector vand -> vnor diff --git a/gcc/config/rs6000/genfusion.pl b/gcc/config/rs6000/genfusion.pl index 62d19c0de031..3fc14e6d5eb7 100755 --- a/gcc/config/rs6000/genfusion.pl +++ b/gcc/config/rs6000/genfusion.pl @@ -254,6 +254,11 @@ sub gen_logical_addsubf "vnand_vnand" => 241, "vorc_vnand" => 244, "veqv_vnand" => 246, + "vnor_vnand" => 247, + "vor_vnand" => 248, + "vxor_vnand" => 249, + "vandc_vnand" => 253, + "vand_vnand" => 254, ); KIND: foreach $kind ('scalar','vector') {