[gcc(refs/users/meissner/heads/work221-sha)] PR target/117251: Improve vector orc to vector eqv fusion

[Michael Meissner]

https://gcc.gnu.org/g:6c38417248ed38b5315095e6dbe951939d0e1307

commit 6c38417248ed38b5315095e6dbe951939d0e1307
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Mon Sep 8 15:23:31 2025 -0400

    PR target/117251: Improve vector orc to vector eqv fusion
    
    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 #16 of 45 to generate the 'XXEVAL' instruction on power10
    and power11 instead of using the Altivec 'VORC' instruction feeding
    into 'VEQV'.  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.
    
    Currently the following code:
    
            vector int a, b, c, d;
            a = ~ ((c | ~ d) ^ b);
    
    Generates:
    
            vorc   t,c,d
            veqv   a,t,b
    
    Now in addition with this patch, if the arguments or result is
    allocated to a traditional FPR register, the GCC compiler will now
    generate the following code instead of adding vector move instructions:
    
            xxeval a,b,c,75
    
    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 patchs into
    the trunk?
    
    2025-09-08  Michael Meissner  <meissner@linux.ibm.com>
    
    gcc/
    
            PR target/117251
            * config/rs6000/fusion.md: Regenerate.
            * config/rs6000/genfusion.pl (gen_logical_addsubf): Add support
            to generate vector orc => eqv fusion if XXEVAL is supported.

Diff:
---
 gcc/config/rs6000/fusion.md    | 15 +++++++++------
 gcc/config/rs6000/genfusion.pl |  1 +
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/gcc/config/rs6000/fusion.md b/gcc/config/rs6000/fusion.md
index f45e65f0217c..f84d0aee5d79 100644
--- a/gcc/config/rs6000/fusion.md
+++ b/gcc/config/rs6000/fusion.md
@@ -2294,20 +2294,23 @@
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector vorc -> veqv
 (define_insn "*fuse_vorc_veqv"
-  [(set (match_operand:VM 3 "altivec_register_operand" "=&0,&1,&v,v")
-        (not:VM (xor:VM (ior: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"))
-                 (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")
+        (not:VM (xor:VM (ior: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"))
+                 (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)"
   "@
    vorc %3,%1,%0\;veqv %3,%3,%2
    vorc %3,%1,%0\;veqv %3,%3,%2
    vorc %3,%1,%0\;veqv %3,%3,%2
+   xxeval %x3,%x2,%x1,%x0,75
    vorc %4,%1,%0\;veqv %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" "*,*,*,xxeval,*")])
 
 ;; logical-logical fusion pattern generated by gen_logical_addsubf
 ;; vector vxor -> veqv
diff --git a/gcc/config/rs6000/genfusion.pl b/gcc/config/rs6000/genfusion.pl
index 720e8d440c2d..8ba1aa081f75 100755
--- a/gcc/config/rs6000/genfusion.pl
+++ b/gcc/config/rs6000/genfusion.pl
@@ -230,6 +230,7 @@ sub gen_logical_addsubf
       "vandc_vxor"  =>  45,
       "vandc_vor"   =>  47,
       "vorc_vnor"   =>  64,
+      "vorc_veqv"   =>  75,
     );
 
     KIND: foreach $kind ('scalar','vector') {