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| author | Tim Northover <tnorthover@apple.com> | 2014-05-02 17:25:02 +0000 |
|---|---|---|
| committer | Tim Northover <tnorthover@apple.com> | 2014-05-02 17:25:02 +0000 |
| commit | b20252764dd2d68e4334dcf127b3b683226dc72b (patch) | |
| tree | ea7f86f72346c12bcce4e0b677702bf534add22c | |
| parent | 3cddd1607c3e48853870275a080d16a63ed0d6ef (diff) | |
| download | llvm-b20252764dd2d68e4334dcf127b3b683226dc72b.tar.gz llvm-b20252764dd2d68e4334dcf127b3b683226dc72b.tar.bz2 llvm-b20252764dd2d68e4334dcf127b3b683226dc72b.tar.xz | |
DAGCombine: prevent formation of illegal ConstantFP nodes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207850 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 15 | ||||
| -rw-r--r-- | test/CodeGen/ARM64/fp-contract-zero.ll | 14 |
2 files changed, 24 insertions, 5 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 290f2a1ea2..de715e4791 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -7181,11 +7181,16 @@ SDValue DAGCombiner::visitFNEG(SDNode *N) { // (fneg (fmul c, x)) -> (fmul -c, x) if (N0.getOpcode() == ISD::FMUL) { ConstantFPSDNode *CFP1 = dyn_cast<ConstantFPSDNode>(N0.getOperand(1)); - if (CFP1) - return DAG.getNode(ISD::FMUL, SDLoc(N), VT, - N0.getOperand(0), - DAG.getNode(ISD::FNEG, SDLoc(N), VT, - N0.getOperand(1))); + if (CFP1) { + APFloat CVal = CFP1->getValueAPF(); + CVal.changeSign(); + if (Level >= AfterLegalizeDAG && + (TLI.isFPImmLegal(CVal, N->getValueType(0)) || + TLI.isOperationLegal(ISD::ConstantFP, N->getValueType(0)))) + return DAG.getNode( + ISD::FMUL, SDLoc(N), VT, N0.getOperand(0), + DAG.getNode(ISD::FNEG, SDLoc(N), VT, N0.getOperand(1))); + } } return SDValue(); diff --git a/test/CodeGen/ARM64/fp-contract-zero.ll b/test/CodeGen/ARM64/fp-contract-zero.ll new file mode 100644 index 0000000000..f982cbb7f5 --- /dev/null +++ b/test/CodeGen/ARM64/fp-contract-zero.ll @@ -0,0 +1,14 @@ +; RUN: llc -mtriple=arm64 -fp-contract=fast -o - %s | FileCheck %s + + +; Make sure we don't try to fold an fneg into +0.0, creating an illegal constant +; -0.0. It's also good, though not essential, that we don't resort to a litpool. +define double @test_fms_fold(double %a, double %b) { +; CHECK-LABEL: test_fms_fold: +; CHECK: fmov {{d[0-9]+}}, xzr +; CHECK: ret + %mul = fmul double %a, 0.000000e+00 + %mul1 = fmul double %b, 0.000000e+00 + %sub = fsub double %mul, %mul1 + ret double %sub +}
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