[IR] Add a dedicated FNeg IR Instruction
The IEEE-754 Standard makes it clear that fneg(x) and
fsub(-0.0, x) are two different operations. The former is a bitwise
operation, while the latter is an arithmetic operation. This patch
creates a dedicated FNeg IR Instruction to model that behavior.
Differential Revision: https://reviews.llvm.org/D53877
llvm-svn: 346774
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index 166ff18..44afbef 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -1451,6 +1451,7 @@
case CatchPad: return 0;
case CatchSwitch: return 0;
case CleanupPad: return 0;
+ case FNeg: return ISD::FNEG;
case Add: return ISD::ADD;
case FAdd: return ISD::FADD;
case Sub: return ISD::SUB;