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| author | Owen Anderson <resistor@mac.com> | 2012-05-02 21:32:35 +0000 |
|---|---|---|
| committer | Owen Anderson <resistor@mac.com> | 2012-05-02 21:32:35 +0000 |
| commit | 363e4b90c0a8dfca87ac847001158c743491c06f (patch) | |
| tree | 298a6f6456c4bede793a06dbc89bd21188b08005 | |
| parent | 4599613dec76683aa1630a4a02082e0dc8ec2706 (diff) | |
| download | external_llvm-363e4b90c0a8dfca87ac847001158c743491c06f.zip external_llvm-363e4b90c0a8dfca87ac847001158c743491c06f.tar.gz external_llvm-363e4b90c0a8dfca87ac847001158c743491c06f.tar.bz2 | |
Teach DAG combine that multiplication by 1.0 can always be constant folded.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156023 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 | ||||
| -rw-r--r-- | test/CodeGen/ARM/fmuls.ll | 9 |
2 files changed, 12 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index e72c8d5..b8f08bf 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -5715,6 +5715,9 @@ SDValue DAGCombiner::visitFMUL(SDNode *N) { if (DAG.getTarget().Options.UnsafeFPMath && ISD::isBuildVectorAllZeros(N1.getNode())) return N1; + // fold (fmul A, 1.0) -> A + if (N1CFP && N1CFP->isExactlyValue(1.0)) + return N0; // fold (fmul X, 2.0) -> (fadd X, X) if (N1CFP && N1CFP->isExactlyValue(+2.0)) return DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0, N0); diff --git a/test/CodeGen/ARM/fmuls.ll b/test/CodeGen/ARM/fmuls.ll index bc118b8..3c3182b 100644 --- a/test/CodeGen/ARM/fmuls.ll +++ b/test/CodeGen/ARM/fmuls.ll @@ -21,3 +21,12 @@ entry: ; CORTEXA8: vmul.f32 d0, d1, d0 ; CORTEXA9: test: ; CORTEXA9: vmul.f32 s{{.}}, s{{.}}, s{{.}} + +; VFP2: test2 +define float @test2(float %a) nounwind { +; CHECK-NOT: mul +; CHECK: mov pc, lr + %ret = fmul float %a, 1.0 + ret float %ret +} + |