diff options
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp | 26 | ||||
| -rw-r--r-- | llvm/test/CodeGen/PowerPC/fma-combine.ll | 101 |
2 files changed, 116 insertions, 11 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp index 24ab65171a1..368e2100031 100644 --- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -5490,9 +5490,20 @@ char TargetLowering::isNegatibleForFree(SDValue Op, SelectionDAG &DAG, EVT VT = Op.getValueType(); const SDNodeFlags Flags = Op->getFlags(); const TargetOptions &Options = DAG.getTarget().Options; - if (!Op.hasOneUse() && !(Op.getOpcode() == ISD::FP_EXTEND && - isFPExtFree(VT, Op.getOperand(0).getValueType()))) - return 0; + if (!Op.hasOneUse()) { + bool IsFreeExtend = Op.getOpcode() == ISD::FP_EXTEND && + isFPExtFree(VT, Op.getOperand(0).getValueType()); + + // If we already have the use of the negated floating constant, it is free + // to negate it even it has multiple uses. + bool IsFreeConstant = + Op.getOpcode() == ISD::ConstantFP && + !getNegatedExpression(Op, DAG, LegalOperations, ForCodeSize) + .use_empty(); + + if (!IsFreeExtend && !IsFreeConstant) + return 0; + } // Don't recurse exponentially. if (Depth > SelectionDAG::MaxRecursionDepth) @@ -5687,14 +5698,7 @@ SDValue TargetLowering::getNegatedExpression(SDValue Op, SelectionDAG &DAG, ForCodeSize, Depth + 1); char V1 = isNegatibleForFree(Op.getOperand(1), DAG, LegalOperations, ForCodeSize, Depth + 1); - // TODO: This is a hack. It is possible that costs have changed between now - // and the initial calls to isNegatibleForFree(). That is because we - // are rewriting the expression, and that may change the number of - // uses (and therefore the cost) of values. If the negation costs are - // equal, only negate this value if it is a constant. Otherwise, try - // operand 1. A better fix would eliminate uses as a cost factor or - // track the change in uses as we rewrite the expression. - if (V0 > V1 || (V0 == V1 && isa<ConstantFPSDNode>(Op.getOperand(0)))) { + if (V0 > V1) { // fold (fneg (fma X, Y, Z)) -> (fma (fneg X), Y, (fneg Z)) SDValue Neg0 = getNegatedExpression( Op.getOperand(0), DAG, LegalOperations, ForCodeSize, Depth + 1); diff --git a/llvm/test/CodeGen/PowerPC/fma-combine.ll b/llvm/test/CodeGen/PowerPC/fma-combine.ll index 88da295201f..8973dc1334d 100644 --- a/llvm/test/CodeGen/PowerPC/fma-combine.ll +++ b/llvm/test/CodeGen/PowerPC/fma-combine.ll @@ -137,3 +137,104 @@ entry: %add = fsub double %mul, %a ret double %add } + +define float @fma_combine_no_ice() { +; CHECK-FAST-LABEL: fma_combine_no_ice: +; CHECK-FAST: # %bb.0: +; CHECK-FAST-NEXT: addis 3, 2, .LCPI4_0@toc@ha +; CHECK-FAST-NEXT: addis 4, 2, .LCPI4_1@toc@ha +; CHECK-FAST-NEXT: lfs 0, .LCPI4_0@toc@l(3) +; CHECK-FAST-NEXT: lfsx 2, 0, 3 +; CHECK-FAST-NEXT: addis 3, 2, .LCPI4_2@toc@ha +; CHECK-FAST-NEXT: lfs 3, .LCPI4_1@toc@l(4) +; CHECK-FAST-NEXT: lfs 1, .LCPI4_2@toc@l(3) +; CHECK-FAST-NEXT: xsmaddasp 3, 2, 0 +; CHECK-FAST-NEXT: xsmaddasp 1, 2, 3 +; CHECK-FAST-NEXT: xsnmsubasp 1, 3, 2 +; CHECK-FAST-NEXT: blr +; +; CHECK-FAST-NOVSX-LABEL: fma_combine_no_ice: +; CHECK-FAST-NOVSX: # %bb.0: +; CHECK-FAST-NOVSX-NEXT: addis 3, 2, .LCPI4_0@toc@ha +; CHECK-FAST-NOVSX-NEXT: lfs 0, .LCPI4_0@toc@l(3) +; CHECK-FAST-NOVSX-NEXT: addis 3, 2, .LCPI4_1@toc@ha +; CHECK-FAST-NOVSX-NEXT: lfs 1, 0(3) +; CHECK-FAST-NOVSX-NEXT: lfs 2, .LCPI4_1@toc@l(3) +; CHECK-FAST-NOVSX-NEXT: addis 3, 2, .LCPI4_2@toc@ha +; CHECK-FAST-NOVSX-NEXT: fmadds 0, 1, 2, 0 +; CHECK-FAST-NOVSX-NEXT: lfs 2, .LCPI4_2@toc@l(3) +; CHECK-FAST-NOVSX-NEXT: fmadds 2, 1, 0, 2 +; CHECK-FAST-NOVSX-NEXT: fnmsubs 1, 0, 1, 2 +; CHECK-FAST-NOVSX-NEXT: blr +; +; CHECK-LABEL: fma_combine_no_ice: +; CHECK: # %bb.0: +; CHECK-NEXT: addis 3, 2, .LCPI4_0@toc@ha +; CHECK-NEXT: addis 4, 2, .LCPI4_1@toc@ha +; CHECK-NEXT: lfs 0, .LCPI4_0@toc@l(3) +; CHECK-NEXT: lfsx 2, 0, 3 +; CHECK-NEXT: addis 3, 2, .LCPI4_2@toc@ha +; CHECK-NEXT: lfs 3, .LCPI4_1@toc@l(4) +; CHECK-NEXT: lfs 1, .LCPI4_2@toc@l(3) +; CHECK-NEXT: xsmaddasp 3, 2, 0 +; CHECK-NEXT: xsmaddasp 1, 2, 3 +; CHECK-NEXT: xsnmsubasp 1, 3, 2 +; CHECK-NEXT: blr + %tmp = load float, float* undef, align 4 + %tmp2 = load float, float* undef, align 4 + %tmp3 = fmul fast float %tmp, 0x3FE372D780000000 + %tmp4 = fadd fast float %tmp3, 1.000000e+00 + %tmp5 = fmul fast float %tmp2, %tmp4 + %tmp6 = load float, float* undef, align 4 + %tmp7 = load float, float* undef, align 4 + %tmp8 = fmul fast float %tmp7, 0x3FE372D780000000 + %tmp9 = fsub fast float -1.000000e+00, %tmp8 + %tmp10 = fmul fast float %tmp9, %tmp6 + %tmp11 = fadd fast float %tmp5, 5.000000e-01 + %tmp12 = fadd fast float %tmp11, %tmp10 + ret float %tmp12 +} + +; This would crash while trying getNegatedExpression(). +define double @getNegatedExpression_crash(double %x, double %y) { +; CHECK-FAST-LABEL: getNegatedExpression_crash: +; CHECK-FAST: # %bb.0: +; CHECK-FAST-NEXT: addis 3, 2, .LCPI5_1@toc@ha +; CHECK-FAST-NEXT: addis 4, 2, .LCPI5_0@toc@ha +; CHECK-FAST-NEXT: lfs 3, .LCPI5_1@toc@l(3) +; CHECK-FAST-NEXT: lfs 4, .LCPI5_0@toc@l(4) +; CHECK-FAST-NEXT: xssubdp 0, 1, 3 +; CHECK-FAST-NEXT: xsmaddadp 3, 1, 4 +; CHECK-FAST-NEXT: xsmaddadp 0, 3, 2 +; CHECK-FAST-NEXT: fmr 1, 0 +; CHECK-FAST-NEXT: blr +; +; CHECK-FAST-NOVSX-LABEL: getNegatedExpression_crash: +; CHECK-FAST-NOVSX: # %bb.0: +; CHECK-FAST-NOVSX-NEXT: addis 3, 2, .LCPI5_0@toc@ha +; CHECK-FAST-NOVSX-NEXT: addis 4, 2, .LCPI5_1@toc@ha +; CHECK-FAST-NOVSX-NEXT: lfs 0, .LCPI5_0@toc@l(3) +; CHECK-FAST-NOVSX-NEXT: lfs 3, .LCPI5_1@toc@l(4) +; CHECK-FAST-NOVSX-NEXT: fmadd 3, 1, 3, 0 +; CHECK-FAST-NOVSX-NEXT: fsub 0, 1, 0 +; CHECK-FAST-NOVSX-NEXT: fmadd 1, 3, 2, 0 +; CHECK-FAST-NOVSX-NEXT: blr +; +; CHECK-LABEL: getNegatedExpression_crash: +; CHECK: # %bb.0: +; CHECK-NEXT: addis 3, 2, .LCPI5_1@toc@ha +; CHECK-NEXT: addis 4, 2, .LCPI5_0@toc@ha +; CHECK-NEXT: lfs 3, .LCPI5_1@toc@l(3) +; CHECK-NEXT: lfs 4, .LCPI5_0@toc@l(4) +; CHECK-NEXT: xssubdp 0, 1, 3 +; CHECK-NEXT: xsmaddadp 3, 1, 4 +; CHECK-NEXT: xsmaddadp 0, 3, 2 +; CHECK-NEXT: fmr 1, 0 +; CHECK-NEXT: blr + %neg = fneg fast double %x + %fma = call fast double @llvm.fma.f64(double %neg, double 42.0, double -1.0) + %add = fadd fast double %x, 1.0 + %fma1 = call fast double @llvm.fma.f64(double %fma, double %y, double %add) + ret double %fma1 +} +declare double @llvm.fma.f64(double, double, double) nounwind readnone |
