http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59835
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Untested patch for kunpckhi:
2014-01-16 Jakub Jelinek <ja...@redhat.com>
* config/i386/i386.md (kunpckhi): Add GPR alternative.
--- gcc/config/i386/i386.md.jj 2014-01-09 21:07:23.000000000 +0100
+++ gcc/config/i386/i386.md 2014-01-16 17:53:54.983352747 +0100
@@ -8486,14 +8486,16 @@ (define_insn "kortestchi"
(set_attr "prefix" "vex")])
(define_insn "kunpckhi"
- [(set (match_operand:HI 0 "register_operand" "=Yk")
+ [(set (match_operand:HI 0 "register_operand" "=Yk,Q")
(ior:HI
(ashift:HI
- (match_operand:HI 1 "register_operand" "Yk")
+ (match_operand:HI 1 "register_operand" "Yk,Q")
(const_int 8))
- (zero_extend:HI (match_operand:QI 2 "register_operand" "Yk"))))]
+ (zero_extend:HI (match_operand:QI 2 "register_operand" "Yk,0"))))]
"TARGET_AVX512F"
- "kunpckbw\t{%2, %1, %0|%0, %1, %2}"
+ "@
+ kunpckbw\t{%2, %1, %0|%0, %1, %2}
+ mov{b}\t{%b1, %h0|%h0, %b1}"
[(set_attr "mode" "HI")
(set_attr "type" "msklog")
(set_attr "prefix" "vex")])
Of course, no real performance testing has been performed, perhaps there should
be one ? or more for the =Q, Q, 0 alternative. Without any ?, we don't ICE or
endlessly consume memory anymore, with one ? we do again.
With -O2 -march=k8 -mavx512f the patch changes (from before r206638 to trunk +
patch):
- kmovw %edi, %k1
- kunpckbw %k1, %k1, %k0
- kmovw %k0, -8(%rsp)
- movd -8(%rsp), %mm0
+ movl %edi, %eax
+ movb %al, %ah
+ movd %eax, %mm0
Dunno of course how that compares performance wise, but at least it is shorter.
For -O2 -mavx512f:
- kmovw %edi, %k1
- kunpckbw %k1, %k1, %k0
- kmovw %k0, -8(%rsp)
+ movl %edi, %eax
+ movl %edi, %edx
+ movb %al, %dh
+ movw %dx, -8(%rsp)
so in this case perhaps using mask registers is better, as we store the result
into memory anyway.
