1 files changed, 47 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index cc7d4be7a78..b0d898738a5 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -796,6 +796,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
       return new StoreInst(II->getArgOperand(0), Ptr);
     }
     break;
+
   case Intrinsic::x86_sse_storeu_ps:
   case Intrinsic::x86_sse2_storeu_pd:
   case Intrinsic::x86_sse2_storeu_dq:
@@ -809,6 +810,52 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     }
     break;
 
+  case Intrinsic::x86_vcvtph2ps_128:
+  case Intrinsic::x86_vcvtph2ps_256: {
+    auto Arg = II->getArgOperand(0);
+    auto ArgType = cast<VectorType>(Arg->getType());
+    auto RetType = cast<VectorType>(II->getType());
+    unsigned ArgWidth = ArgType->getNumElements();
+    unsigned RetWidth = RetType->getNumElements();
+    assert(RetWidth <= ArgWidth && "Unexpected input/return vector widths");
+    assert(ArgType->isIntOrIntVectorTy() &&
+           ArgType->getScalarSizeInBits() == 16 &&
+           "CVTPH2PS input type should be 16-bit integer vector");
+    assert(RetType->getScalarType()->isFloatTy() &&
+           "CVTPH2PS output type should be 32-bit float vector");
+
+    // Constant folding: Convert to generic half to single conversion.
+    if (auto CIZero = dyn_cast<ConstantAggregateZero>(Arg))
+      return ReplaceInstUsesWith(*II, ConstantAggregateZero::get(RetType));
+
+    if (auto CIHalf = dyn_cast<ConstantDataVector>(Arg)) {
+      auto VectorHalfAsShorts = Arg;
+      if (RetWidth < ArgWidth) {
+        SmallVector<int, 8> SubVecMask;
+        for (unsigned i = 0; i != RetWidth; ++i)
+          SubVecMask.push_back((int)i);
+        VectorHalfAsShorts = Builder->CreateShuffleVector(
+            Arg, UndefValue::get(ArgType), SubVecMask);
+      }
+
+      auto VectorHalfType =
+          VectorType::get(Type::getHalfTy(II->getContext()), RetWidth);
+      auto VectorHalfs =
+          Builder->CreateBitCast(VectorHalfAsShorts, VectorHalfType);
+      auto VectorFloats = Builder->CreateFPExt(VectorHalfs, RetType);
+      return ReplaceInstUsesWith(*II, VectorFloats);
+    }
+
+    // We only use the lowest lanes of the argument.
+    APInt DemandedElts = APInt::getLowBitsSet(ArgWidth, RetWidth);
+    APInt UndefElts(ArgWidth, 0);
+    if (Value *V = SimplifyDemandedVectorElts(Arg, DemandedElts, UndefElts)) {
+      II->setArgOperand(0, V);
+      return II;
+    }
+    break;
+  }
+
   case Intrinsic::x86_sse_cvtss2si:
   case Intrinsic::x86_sse_cvtss2si64:
   case Intrinsic::x86_sse_cvttss2si: