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| author | Tim Northover <tnorthover@apple.com> | 2015-07-17 03:31:50 +0000 |
|---|---|---|
| committer | Tim Northover <tnorthover@apple.com> | 2015-07-17 03:31:50 +0000 |
| commit | a5740e08744403031f5d2a0b4baa614a4d6bfad9 (patch) | |
| tree | 3d3be72f37e0beafd03d38f783cc1995fd76ee07 /llvm | |
| parent | 8101f570f83cf7643b64d38d71dfe00cea3ac6ee (diff) | |
| download | bcm5719-llvm-a5740e08744403031f5d2a0b4baa614a4d6bfad9.tar.gz bcm5719-llvm-a5740e08744403031f5d2a0b4baa614a4d6bfad9.zip | |
AArch64: add comment missed out from earlier patch.
Helps explain some of the background behind this bit of code.
llvm-svn: 242503
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp index cf33782365b..1a1b58bd26e 100644 --- a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp +++ b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp @@ -2062,6 +2062,10 @@ SDNode *AArch64DAGToDAGISel::SelectLIBM(SDNode *N) { SmallVector<SDValue, 2> Ops; Ops.push_back(In); + // C11 leaves it implementation-defined whether these operations trigger an + // inexact exception. IEEE says they don't. Unfortunately, Darwin decided + // they do so we sometimes have to insert a special instruction just to set + // the right bit in FPSR. if (Subtarget->isTargetDarwin() && !TM.Options.UnsafeFPMath) { SDNode *FRINTX = CurDAG->getMachineNode(FRINTXOpc, dl, VT, MVT::Glue, In); Ops.push_back(SDValue(FRINTX, 1)); |
