[PATCH] D141782: [X86] Don't fold select for vXi1 on X86 target.

[LuoYuanke via Phabricator via llvm-commits]

LuoYuanke created this revision.
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Since there is no mask instruction for vXi1 with avx512f in X86 target.
Folding select for vXi1 doesn't help to reduce instructions.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D141782

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/fold-select.ll


Index: llvm/test/CodeGen/X86/fold-select.ll
===================================================================
--- llvm/test/CodeGen/X86/fold-select.ll
+++ llvm/test/CodeGen/X86/fold-select.ll
@@ -4,16 +4,9 @@
 define <8 x float> @select_and_v8i1(<8 x i1> %a, <8 x i1> %b, <8 x i1> %c, <8 x float> %d) {
 ; CHECK-LABEL: select_and_v8i1:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    vpsllw $15, %xmm2, %xmm4
+; CHECK-NEXT:    vpternlogq $200, %xmm1, %xmm2, %xmm0
 ; CHECK-NEXT:    vpsllw $15, %xmm0, %xmm0
 ; CHECK-NEXT:    vpmovw2m %xmm0, %k1
-; CHECK-NEXT:    vpxor %xmm0, %xmm0, %xmm0
-; CHECK-NEXT:    vpcmpgtw %xmm4, %xmm0, %k0 {%k1}
-; CHECK-NEXT:    vpand %xmm1, %xmm2, %xmm0
-; CHECK-NEXT:    vpsllw $15, %xmm0, %xmm0
-; CHECK-NEXT:    vpmovw2m %xmm0, %k2
-; CHECK-NEXT:    kandnb %k2, %k1, %k1
-; CHECK-NEXT:    korb %k1, %k0, %k1
 ; CHECK-NEXT:    vbroadcastss {{.*#+}} ymm0 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0]
 ; CHECK-NEXT:    vmovaps %ymm3, %ymm0 {%k1}
 ; CHECK-NEXT:    retq
@@ -26,15 +19,13 @@
 define <8 x float> @select_or_v8i1(<8 x i1> %a, <8 x i1> %b, <8 x i1> %c, <8 x float> %d) {
 ; CHECK-LABEL: select_or_v8i1:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    vpsllw $15, %xmm2, %xmm4
-; CHECK-NEXT:    vpsllw $15, %xmm0, %xmm0
-; CHECK-NEXT:    vpmovw2m %xmm0, %k1
-; CHECK-NEXT:    vpxor %xmm0, %xmm0, %xmm0
-; CHECK-NEXT:    vpcmpgtw %xmm4, %xmm0, %k0 {%k1}
-; CHECK-NEXT:    vpor %xmm1, %xmm2, %xmm0
+; CHECK-NEXT:    vpsllw $15, %xmm2, %xmm2
+; CHECK-NEXT:    vpmovw2m %xmm2, %k0
+; CHECK-NEXT:    vpsllw $15, %xmm1, %xmm1
+; CHECK-NEXT:    vpmovw2m %xmm1, %k1
 ; CHECK-NEXT:    vpsllw $15, %xmm0, %xmm0
 ; CHECK-NEXT:    vpmovw2m %xmm0, %k2
-; CHECK-NEXT:    kandnb %k2, %k1, %k1
+; CHECK-NEXT:    kandnb %k1, %k2, %k1
 ; CHECK-NEXT:    korb %k1, %k0, %k1
 ; CHECK-NEXT:    vbroadcastss {{.*#+}} ymm0 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0]
 ; CHECK-NEXT:    vmovaps %ymm3, %ymm0 {%k1}
Index: llvm/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -34853,8 +34853,13 @@
     return false;
   if (!Subtarget.hasVLX() && !VT.is512BitVector())
     return false;
+  if (!VT.isSimple())
+    return false;
   if (!VT.isVector())
     return false;
+  // Not for i1 vectors because there is no mask instruction for vXi1.
+  if (VT.getSimpleVT().getScalarType() == MVT::i1)
+    return false;
 
   return true;
 }


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