[llvm] r333771 - [Hexagon] Avoid UB when shifting unsigned integer left by 32

[Krzysztof Parzyszek via llvm-commits]

Author: kparzysz
Date: Fri Jun  1 08:39:10 2018
New Revision: 333771

URL: http://llvm.org/viewvc/llvm-project?rev=333771&view=rev
Log:
[Hexagon] Avoid UB when shifting unsigned integer left by 32

Modified:
    llvm/trunk/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp

Modified: llvm/trunk/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp?rev=333771&r1=333770&r2=333771&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp (original)
+++ llvm/trunk/lib/Target/Hexagon/HexagonISelLoweringHVX.cpp Fri Jun  1 08:39:10 2018
@@ -1169,16 +1169,17 @@ HexagonTargetLowering::LowerHvxCttz(SDVa
   // Calculate the vectors of 1 and bitwidth(x).
   MVT ElemTy = ty(InpV).getVectorElementType();
   unsigned ElemWidth = ElemTy.getSizeInBits();
-  uint32_t Splat1 = 0, SplatW = 0;
+  // Using uint64_t because a shift by 32 can happen.
+  uint64_t Splat1 = 0, SplatW = 0;
   assert(isPowerOf2_32(ElemWidth) && ElemWidth <= 32);
   for (unsigned i = 0; i != 32/ElemWidth; ++i) {
     Splat1 = (Splat1 << ElemWidth) | 1;
     SplatW = (SplatW << ElemWidth) | ElemWidth;
   }
   SDValue Vec1 = DAG.getNode(HexagonISD::VSPLATW, dl, ResTy,
-                             DAG.getConstant(Splat1, dl, MVT::i32));
+                             DAG.getConstant(uint32_t(Splat1), dl, MVT::i32));
   SDValue VecW = DAG.getNode(HexagonISD::VSPLATW, dl, ResTy,
-                             DAG.getConstant(SplatW, dl, MVT::i32));
+                             DAG.getConstant(uint32_t(SplatW), dl, MVT::i32));
   SDValue VecN1 = DAG.getNode(HexagonISD::VSPLATW, dl, ResTy,
                               DAG.getConstant(-1, dl, MVT::i32));
   // Do not use DAG.getNOT, because that would create BUILD_VECTOR with