[PATCH] D19198: [X86][AVX] Generalized matching for target shuffle combines

[Elena Demikhovsky via llvm-commits]

delena added inline comments.

================
Comment at: lib/Target/X86/X86ISelLowering.cpp:24007
@@ +24006,3 @@
+
+  if (!FloatDomain)
+    return false;
----------------
Why float/int is so important? I think that a one cycle penalty for switching domains was on old (SSE) processors.

================
Comment at: test/CodeGen/X86/vector-shuffle-combining-avx512bw.ll:25
@@ -24,4 +24,3 @@
 ; CHECK:       # BB#0:
-; CHECK-NEXT:    vmovdqa64 {{.*#+}} zmm2 = [0,0,2,2,4,4,6,6]
-; CHECK-NEXT:    vpermt2pd %zmm1, %zmm2, %zmm0
+; CHECK-NEXT:    vmovddup {{.*#+}} zmm0 = zmm0[0,0,2,2,4,4,6,6]
 ; CHECK-NEXT:    retq
----------------
What happens when mask is not -1?


Repository:
  rL LLVM

http://reviews.llvm.org/D19198