diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 22 | ||||
| -rw-r--r-- | test/CodeGen/X86/dagcombine_unsafe_math.ll | 14 |
2 files changed, 31 insertions, 5 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 61603e18f5..b2f970b447 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -5835,14 +5835,25 @@ SDValue DAGCombiner::visitFADD(SDNode *N) { DAG.getNode(ISD::FADD, N->getDebugLoc(), VT, N0.getOperand(1), N1)); + // No FP constant should be created after legalization as Instruction + // Selection pass has hard time in dealing with FP constant. + // + // We don't need test this condition for transformation like following, as + // the DAG being transformed implies it is legal to take FP constant as + // operand. + // + // (fadd (fmul c, x), x) -> (fmul c+1, x) + // + bool AllowNewFpConst = (Level < AfterLegalizeDAG); + // If allow, fold (fadd (fneg x), x) -> 0.0 - if (DAG.getTarget().Options.UnsafeFPMath && + if (AllowNewFpConst && DAG.getTarget().Options.UnsafeFPMath && N0.getOpcode() == ISD::FNEG && N0.getOperand(0) == N1) { return DAG.getConstantFP(0.0, VT); } // If allow, fold (fadd x, (fneg x)) -> 0.0 - if (DAG.getTarget().Options.UnsafeFPMath && + if (AllowNewFpConst && DAG.getTarget().Options.UnsafeFPMath && N1.getOpcode() == ISD::FNEG && N1.getOperand(0) == N0) { return DAG.getConstantFP(0.0, VT); } @@ -5944,7 +5955,7 @@ SDValue DAGCombiner::visitFADD(SDNode *N) { } } - if (N0.getOpcode() == ISD::FADD) { + if (N0.getOpcode() == ISD::FADD && AllowNewFpConst) { ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N0.getOperand(0)); // (fadd (fadd x, x), x) -> (fmul 3.0, x) if (!CFP && N0.getOperand(0) == N0.getOperand(1) && @@ -5954,7 +5965,7 @@ SDValue DAGCombiner::visitFADD(SDNode *N) { } } - if (N1.getOpcode() == ISD::FADD) { + if (N1.getOpcode() == ISD::FADD && AllowNewFpConst) { ConstantFPSDNode *CFP10 = dyn_cast<ConstantFPSDNode>(N1.getOperand(0)); // (fadd x, (fadd x, x)) -> (fmul 3.0, x) if (!CFP10 && N1.getOperand(0) == N1.getOperand(1) && @@ -5965,7 +5976,8 @@ SDValue DAGCombiner::visitFADD(SDNode *N) { } // (fadd (fadd x, x), (fadd x, x)) -> (fmul 4.0, x) - if (N0.getOpcode() == ISD::FADD && N1.getOpcode() == ISD::FADD && + if (AllowNewFpConst && + N0.getOpcode() == ISD::FADD && N1.getOpcode() == ISD::FADD && N0.getOperand(0) == N0.getOperand(1) && N1.getOperand(0) == N1.getOperand(1) && N0.getOperand(0) == N1.getOperand(0)) { diff --git a/test/CodeGen/X86/dagcombine_unsafe_math.ll b/test/CodeGen/X86/dagcombine_unsafe_math.ll index a3221dea5b..592cf1bec2 100644 --- a/test/CodeGen/X86/dagcombine_unsafe_math.ll +++ b/test/CodeGen/X86/dagcombine_unsafe_math.ll @@ -40,3 +40,17 @@ define float @test4(float %x, float %y) { ; CHECK: test4 ; CHECK: vaddss } + +; rdar://13445387 +; "x + x + x => 3.0 * x" should be disabled after legalization because +; Instruction-Selection dosen't know how to handle "3.0" +; +define float @test5() { + %mul.i.i151 = fmul <4 x float> zeroinitializer, zeroinitializer + %vecext.i8.i152 = extractelement <4 x float> %mul.i.i151, i32 1 + %vecext1.i9.i153 = extractelement <4 x float> %mul.i.i151, i32 0 + %add.i10.i154 = fadd float %vecext1.i9.i153, %vecext.i8.i152 + %vecext.i7.i155 = extractelement <4 x float> %mul.i.i151, i32 2 + %add.i.i156 = fadd float %vecext.i7.i155, %add.i10.i154 + ret float %add.i.i156 +} |