diff options
| author | Duncan Sands <baldrick@free.fr> | 2012-04-08 18:08:12 +0000 |
|---|---|---|
| committer | Duncan Sands <baldrick@free.fr> | 2012-04-08 18:08:12 +0000 |
| commit | 3ef3fcfc0414b96d626b706c6151596684b7d134 (patch) | |
| tree | d3be66c997afe87dfd18329a2c371ba40fde5bb6 /lib/CodeGen | |
| parent | f873dde50264ffab16f3d12eaec8be91edfcc131 (diff) | |
Only have codegen turn fdiv by a constant into fmul by the reciprocal
when -ffast-math, i.e. don't just always do it if the reciprocal can
be formed exactly. There is already an IR level transform that does
that, and it does it more carefully.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154296 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index ebffb8562e..f1b9f4385e 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -5725,16 +5725,14 @@ SDValue DAGCombiner::visitFDIV(SDNode *N) { if (N0CFP && N1CFP && VT != MVT::ppcf128) return DAG.getNode(ISD::FDIV, N->getDebugLoc(), VT, N0, N1); - // fold (fdiv X, c2) -> fmul X, 1/c2 if there is no precision loss or if - // losing precision is acceptable. - if (N1CFP && VT != MVT::ppcf128) { + // fold (fdiv X, c2) -> fmul X, 1/c2 if losing precision is acceptable. + if (N1CFP && VT != MVT::ppcf128 && DAG.getTarget().Options.UnsafeFPMath) { // Compute the reciprocal 1.0 / c2. APFloat N1APF = N1CFP->getValueAPF(); APFloat Recip(N1APF.getSemantics(), 1); // 1.0 APFloat::opStatus st = Recip.divide(N1APF, APFloat::rmNearestTiesToEven); // Only do the transform if the reciprocal is not too horrible (eg not NaN). - if (st == APFloat::opOK || (st == APFloat::opInexact && - DAG.getTarget().Options.UnsafeFPMath)) + if (st == APFloat::opOK || st == APFloat::opInexact) return DAG.getNode(ISD::FMUL, N->getDebugLoc(), VT, N0, DAG.getConstantFP(Recip, VT)); } |