[GlobalISel] Fix buildZExtInReg creating new register.

Fix a bug where buildZExtInReg will create and use a new register instead of using the register from parameter DstOp Res.

Reviewed By: arsenm, foad

Differential Revision: https://reviews.llvm.org/D101871

diff --git a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index bde442a..1f86bfa 100644 (file)
--- a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -492,7 +492,7 @@ MachineInstrBuilder MachineIRBuilder::buildZExtInReg(const DstOp &Res,
   LLT ResTy = Res.getLLTTy(*getMRI());
   auto Mask = buildConstant(
       ResTy, APInt::getLowBitsSet(ResTy.getScalarSizeInBits(), ImmOp));
-  return buildAnd(ResTy, Op, Mask);
+  return buildAnd(Res, Op, Mask);
 }
 
 MachineInstrBuilder MachineIRBuilder::buildCast(const DstOp &Dst,