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);        veqv   t,c,d    xxeval a,b,c,d,96
                                        vnor   a,t,b

        a = (c ^ d) ^ b;                vxor   t,c,d    xxeval a,b,c,d,105
                                        vxor   a,t,b

        a = (c ^ d) | b;                vxor   t,c,d    xxeval a,b,c,d,111
                                        vor    a,t,b

        a = ~ ((~ (c | d)) | b);        vnor   t,c,d    xxeval a,b,c,d,112
                                        vnor   a,t,b

        a = (c | d) ^ b;                vor    t,c,d    xxeval a,b,c,d,120
                                        vxor   a,t,b

        a = (c | d) | b;                vor    t,c,d    xxeval a,b,c,d,127
                                        vor    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

2026-07-01  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.

---
 gcc/config/rs6000/fusion.md    | 90 ++++++++++++++++++++--------------
 gcc/config/rs6000/genfusion.pl |  6 +++
 2 files changed, 60 insertions(+), 36 deletions(-)

diff --git a/gcc/config/rs6000/fusion.md b/gcc/config/rs6000/fusion.md
index 79bfc9e238a..84cf352b477 100644
--- a/gcc/config/rs6000/fusion.md
+++ b/gcc/config/rs6000/fusion.md
@@ -2513,20 +2513,23 @@ (define_insn "*fuse_vandc_vnor"
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector veqv -> vnor
 (define_insn "*fuse_veqv_vnor"
-  [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
-        (and:VM (not: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")
+        (and:VM (not: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)"
   "@
    veqv %3,%1,%0\;vnor %3,%3,%2
    veqv %3,%1,%0\;vnor %3,%3,%2
    veqv %3,%1,%0\;vnor %3,%3,%2
+   xxeval %x3,%x2,%x1,%x0,96
    veqv %4,%1,%0\;vnor %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 vnand -> vnor
@@ -2552,20 +2555,23 @@ (define_insn "*fuse_vnand_vnor"
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector vnor -> vnor
 (define_insn "*fuse_vnor_vnor"
-  [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
-        (and: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")
+        (and: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\;vnor %3,%3,%2
    vnor %3,%1,%0\;vnor %3,%3,%2
    vnor %3,%1,%0\;vnor %3,%3,%2
+   xxeval %x3,%x2,%x1,%x0,112
    vnor %4,%1,%0\;vnor %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 -> vnor
@@ -2723,20 +2729,23 @@ (define_insn "*fuse_vnor_vor"
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector vor -> vor
 (define_insn "*fuse_vor_vor"
-  [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
-        (ior: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"))
-                 (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 (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"))
+                 (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\;vor %3,%3,%2
    vor %3,%1,%0\;vor %3,%3,%2
    vor %3,%1,%0\;vor %3,%3,%2
+   xxeval %x3,%x2,%x1,%x0,127
    vor %4,%1,%0\;vor %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 -> vor
@@ -2759,20 +2768,23 @@ (define_insn "*fuse_vorc_vor"
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector vxor -> vor
 (define_insn "*fuse_vxor_vor"
-  [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
-        (ior: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"))
-                 (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 (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"))
+                 (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\;vor %3,%3,%2
    vxor %3,%1,%0\;vor %3,%3,%2
    vxor %3,%1,%0\;vor %3,%3,%2
+   xxeval %x3,%x2,%x1,%x0,111
    vxor %4,%1,%0\;vor %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 -> vorc
@@ -3020,20 +3032,23 @@ (define_insn "*fuse_vnor_vxor"
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector vor -> vxor
 (define_insn "*fuse_vor_vxor"
-  [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
-        (xor: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"))
-                 (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")
+        (xor: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"))
+                 (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\;vxor %3,%3,%2
    vor %3,%1,%0\;vxor %3,%3,%2
    vor %3,%1,%0\;vxor %3,%3,%2
+   xxeval %x3,%x2,%x1,%x0,120
    vor %4,%1,%0\;vxor %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 -> vxor
@@ -3056,20 +3071,23 @@ (define_insn "*fuse_vorc_vxor"
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector vxor -> vxor
 (define_insn "*fuse_vxor_vxor"
-  [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
-        (xor: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"))
-                 (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")
+        (xor: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"))
+                 (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\;vxor %3,%3,%2
    vxor %3,%1,%0\;vxor %3,%3,%2
    vxor %3,%1,%0\;vxor %3,%3,%2
+   xxeval %x3,%x2,%x1,%x0,105
    vxor %4,%1,%0\;vxor %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,*")])
 
 ;; add-add fusion pattern generated by gen_addadd
 (define_insn "*fuse_add_add"
diff --git a/gcc/config/rs6000/genfusion.pl b/gcc/config/rs6000/genfusion.pl
index d983144b084..5fec485cdaa 100755
--- a/gcc/config/rs6000/genfusion.pl
+++ b/gcc/config/rs6000/genfusion.pl
@@ -232,6 +232,12 @@ sub gen_logical_addsubf
       "vorc_vnor"   =>  64,
       "vorc_veqv"   =>  75,
       "vorc_vorc"   =>  79,
+      "veqv_vnor"   =>  96,
+      "vxor_vxor"   => 105,
+      "vxor_vor"    => 111,
+      "vnor_vnor"   => 112,
+      "vor_vxor"    => 120,
+      "vor_vor"     => 127,
     );
 
     KIND: foreach $kind ('scalar','vector') {
-- 
2.54.0


-- 
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: [email protected]

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