diff options
| author | Mon P Wang <wangmp@apple.com> | 2009-01-31 06:07:45 +0000 |
|---|---|---|
| committer | Mon P Wang <wangmp@apple.com> | 2009-01-31 06:07:45 +0000 |
| commit | a7b6cff99f5015120f828c316823cb32eed93901 (patch) | |
| tree | a046b83051e726f491d34728317c9eb396f50f58 /lib/CodeGen/SelectionDAG/SelectionDAG.cpp | |
| parent | 9729c5ad3413d3b69d4bc41aa918a7a8dd6bf9f0 (diff) | |
If unsafe FP optimization is not set, don't allow -(A-B) => B-A because
when A==B, -0.0 != +0.0.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63474 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/SelectionDAG.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index bda9d934a4..f5287b0cf2 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -2357,7 +2357,8 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, return Operand.getOperand(0); break; case ISD::FNEG: - if (OpOpcode == ISD::FSUB) // -(X-Y) -> (Y-X) + // -(X-Y) -> (Y-X) is unsafe because when X==Y, -0.0 != +0.0 + if (UnsafeFPMath && OpOpcode == ISD::FSUB) return getNode(ISD::FSUB, VT, Operand.getNode()->getOperand(1), Operand.getNode()->getOperand(0)); if (OpOpcode == ISD::FNEG) // --X -> X |