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| 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 | cf9ba823240ec6d3682ba2ddeab5cdcf04092c77 (patch) | |
| tree | 01955ca4ac9d26f7b80c37f724ccf279d764065c /llvm/lib/CodeGen | |
| parent | 3b585af0ecddfa8b09f0e2d329138094c689164f (diff) | |
| download | bcm5719-llvm-cf9ba823240ec6d3682ba2ddeab5cdcf04092c77.tar.gz bcm5719-llvm-cf9ba823240ec6d3682ba2ddeab5cdcf04092c77.zip | |
If unsafe FP optimization is not set, don't allow -(A-B) => B-A because
when A==B, -0.0 != +0.0.
llvm-svn: 63474
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index bda9d934a41..f5287b0cf2c 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/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 |
