[PATCH] D154213: [X86][FP16] Fix mis-combination from FMULC to FCMULC

[Phoebe Wang via Phabricator via llvm-commits]

pengfei created this revision.
pengfei added reviewers: RKSimon, FreddyYe, LuoYuanke, craig.topper.
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The combination was designed to combine a negative imaginary value
rather then a full negative complex value.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D154213

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/avx512fp16-combine-xor-vfmulc.ll


Index: llvm/test/CodeGen/X86/avx512fp16-combine-xor-vfmulc.ll
===================================================================
--- llvm/test/CodeGen/X86/avx512fp16-combine-xor-vfmulc.ll
+++ llvm/test/CodeGen/X86/avx512fp16-combine-xor-vfmulc.ll
@@ -69,8 +69,10 @@
 define dso_local <32 x half> @test5(<32 x half> noundef %a, <32 x half> noundef %b) local_unnamed_addr #0 {
 ; CHECK-LABEL: test5:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    vfcmulcph %zmm1, %zmm0, %zmm2
-; CHECK-NEXT:    vmovaps %zmm2, %zmm0
+; CHECK-NEXT:    vpbroadcastw {{.*#+}} zmm2 = [-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0,-0.0E+0]
+; CHECK-NEXT:    vpxorq %zmm2, %zmm1, %zmm2
+; CHECK-NEXT:    vfmulcph %zmm2, %zmm0, %zmm1
+; CHECK-NEXT:    vmovaps %zmm1, %zmm0
 ; CHECK-NEXT:    retq
 entry:
   %fneg = fneg <32 x half> %b
Index: llvm/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -52865,7 +52865,7 @@
       }
     }
     if (const auto *CF = dyn_cast<ConstantFP>(c))
-      return CF->isNegativeZeroValue();
+      return CF->getType()->isFloatTy() && CF->isNegativeZeroValue();
     return false;
   };
   auto combineConjugation = [&](SDValue &r) {


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