Don't create usless casts for same-bith-width floating point casts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32475 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 2aa0524dfd0565abb0827e8326dec291a558269c..710b738cd245f90ead5ce21c0531259061b7ea8e 100644 (file)
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -1531,9 +1531,10 @@ Constant *ConstantExpr::getFPCast(Constant *C, const Type *Ty) {
          "Invalid cast");
   unsigned SrcBits = C->getType()->getPrimitiveSizeInBits();
   unsigned DstBits = Ty->getPrimitiveSizeInBits();
+  if (SrcBits == DstBits)
+    return C; // Avoid a useless cast
   Instruction::CastOps opcode =
-    (SrcBits == DstBits ? Instruction::BitCast :
-     (SrcBits > DstBits ? Instruction::FPTrunc : Instruction::FPExt));
+     (SrcBits > DstBits ? Instruction::FPTrunc : Instruction::FPExt);
   return getCast(opcode, C, Ty);
 }