diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | 32 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/fabs.ll | 128 |
2 files changed, 91 insertions, 69 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp index 1f89ca635a9..ff682acd3fd 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -1569,7 +1569,37 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) { // NOTE: if we wanted to, this is where to detect MIN/MAX } - // NOTE: if we wanted to, this is where to detect ABS + + // Canonicalize select with fcmp to fabs(). -0.0 makes this tricky. We need + // fast-math-flags (nsz) or fsub with +0.0 (not fneg) for this to work. We + // also require nnan because we do not want to unintentionally change the + // sign of a NaN value. + Value *X = FCI->getOperand(0); + FCmpInst::Predicate Pred = FCI->getPredicate(); + if (match(FCI->getOperand(1), m_AnyZeroFP()) && FCI->hasNoNaNs()) { + // (X <= +/-0.0) ? (0.0 - X) : X --> fabs(X) + // (X > +/-0.0) ? X : (0.0 - X) --> fabs(X) + if ((X == FalseVal && match(TrueVal, m_FSub(m_Zero(), m_Specific(X))) && + Pred == FCmpInst::FCMP_OLE) || + (X == TrueVal && match(FalseVal, m_FSub(m_Zero(), m_Specific(X))) && + Pred == FCmpInst::FCMP_OGT)) { + Value *Fabs = Builder.CreateIntrinsic(Intrinsic::fabs, { X }, FCI); + return replaceInstUsesWith(SI, Fabs); + } + // With nsz: + // (X < +/-0.0) ? -X : X --> fabs(X) + // (X <= +/-0.0) ? -X : X --> fabs(X) + // (X > +/-0.0) ? X : -X --> fabs(X) + // (X >= +/-0.0) ? X : -X --> fabs(X) + if (FCI->hasNoSignedZeros() && + ((X == FalseVal && match(TrueVal, m_FNeg(m_Specific(X))) && + (Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_OLE)) || + (X == TrueVal && match(FalseVal, m_FNeg(m_Specific(X))) && + (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_OGE)))) { + Value *Fabs = Builder.CreateIntrinsic(Intrinsic::fabs, { X }, FCI); + return replaceInstUsesWith(SI, Fabs); + } + } } // See if we are selecting two values based on a comparison of the two values. diff --git a/llvm/test/Transforms/InstCombine/fabs.ll b/llvm/test/Transforms/InstCombine/fabs.ll index 023e2a681ee..87ab0bdc7a6 100644 --- a/llvm/test/Transforms/InstCombine/fabs.ll +++ b/llvm/test/Transforms/InstCombine/fabs.ll @@ -246,15 +246,29 @@ define double @multi_use_fabs_fpext(float %x) { ret double %fabs } -; X <= 0.0 ? (0.0 - X) : X --> fabs(X) +; Negative test for the fabs folds below: we require nnan, so +; we won't always clear the sign bit of a NaN value. define double @select_fcmp_ole_zero(double %x) { ; CHECK-LABEL: @select_fcmp_ole_zero( -; CHECK-NEXT: [[LEZERO:%.*]] = fcmp nnan ole double [[X:%.*]], 0.000000e+00 +; CHECK-NEXT: [[LEZERO:%.*]] = fcmp ole double [[X:%.*]], 0.000000e+00 ; CHECK-NEXT: [[NEGX:%.*]] = fsub double 0.000000e+00, [[X]] ; CHECK-NEXT: [[FABS:%.*]] = select i1 [[LEZERO]], double [[NEGX]], double [[X]] ; CHECK-NEXT: ret double [[FABS]] ; + %lezero = fcmp ole double %x, 0.0 + %negx = fsub double 0.0, %x + %fabs = select i1 %lezero, double %negx, double %x + ret double %fabs +} + +; X <= 0.0 ? (0.0 - X) : X --> fabs(X) + +define double @select_fcmp_nnan_ole_zero(double %x) { +; CHECK-LABEL: @select_fcmp_nnan_ole_zero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan double @llvm.fabs.f64(double [[X:%.*]]) +; CHECK-NEXT: ret double [[TMP1]] +; %lezero = fcmp nnan ole double %x, 0.0 %negx = fsub double 0.0, %x %fabs = select i1 %lezero, double %negx, double %x @@ -263,12 +277,10 @@ define double @select_fcmp_ole_zero(double %x) { ; X <= -0.0 ? (0.0 - X) : X --> fabs(X) -define float @select_fcmp_ole_negzero(float %x) { -; CHECK-LABEL: @select_fcmp_ole_negzero( -; CHECK-NEXT: [[LEZERO:%.*]] = fcmp nnan ole float [[X:%.*]], -0.000000e+00 -; CHECK-NEXT: [[NEGX:%.*]] = fsub float 0.000000e+00, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[LEZERO]], float [[NEGX]], float [[X]] -; CHECK-NEXT: ret float [[FABS]] +define float @select_fcmp_nnan_ole_negzero(float %x) { +; CHECK-LABEL: @select_fcmp_nnan_ole_negzero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan float @llvm.fabs.f32(float [[X:%.*]]) +; CHECK-NEXT: ret float [[TMP1]] ; %lezero = fcmp nnan ole float %x, -0.0 %negx = fsub float 0.0, %x @@ -278,12 +290,10 @@ define float @select_fcmp_ole_negzero(float %x) { ; X > 0.0 ? X : (0.0 - X) --> fabs(X) -define fp128 @select_fcmp_ogt_zero(fp128 %x) { -; CHECK-LABEL: @select_fcmp_ogt_zero( -; CHECK-NEXT: [[GTZERO:%.*]] = fcmp nnan ogt fp128 [[X:%.*]], 0xL00000000000000000000000000000000 -; CHECK-NEXT: [[NEGX:%.*]] = fsub fp128 0xL00000000000000000000000000000000, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[GTZERO]], fp128 [[X]], fp128 [[NEGX]] -; CHECK-NEXT: ret fp128 [[FABS]] +define fp128 @select_fcmp_nnan_ogt_zero(fp128 %x) { +; CHECK-LABEL: @select_fcmp_nnan_ogt_zero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan fp128 @llvm.fabs.f128(fp128 [[X:%.*]]) +; CHECK-NEXT: ret fp128 [[TMP1]] ; %gtzero = fcmp nnan ogt fp128 %x, zeroinitializer %negx = fsub fp128 zeroinitializer, %x @@ -293,12 +303,10 @@ define fp128 @select_fcmp_ogt_zero(fp128 %x) { ; X > -0.0 ? X : (0.0 - X) --> fabs(X) -define half @select_fcmp_ogt_negzero(half %x) { -; CHECK-LABEL: @select_fcmp_ogt_negzero( -; CHECK-NEXT: [[GTZERO:%.*]] = fcmp nnan ogt half [[X:%.*]], 0xH8000 -; CHECK-NEXT: [[NEGX:%.*]] = fsub half 0xH0000, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[GTZERO]], half [[X]], half [[NEGX]] -; CHECK-NEXT: ret half [[FABS]] +define half @select_fcmp_nnan_ogt_negzero(half %x) { +; CHECK-LABEL: @select_fcmp_nnan_ogt_negzero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan half @llvm.fabs.f16(half [[X:%.*]]) +; CHECK-NEXT: ret half [[TMP1]] ; %gtzero = fcmp nnan ogt half %x, -0.0 %negx = fsub half 0.0, %x @@ -308,12 +316,10 @@ define half @select_fcmp_ogt_negzero(half %x) { ; X < 0.0 ? -X : X --> fabs(X) -define double @select_fcmp_nsz_olt_zero(double %x) { -; CHECK-LABEL: @select_fcmp_nsz_olt_zero( -; CHECK-NEXT: [[LTZERO:%.*]] = fcmp nnan nsz olt double [[X:%.*]], 0.000000e+00 -; CHECK-NEXT: [[NEGX:%.*]] = fsub double -0.000000e+00, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[LTZERO]], double [[NEGX]], double [[X]] -; CHECK-NEXT: ret double [[FABS]] +define double @select_fcmp_nnan_nsz_olt_zero(double %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_olt_zero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz double @llvm.fabs.f64(double [[X:%.*]]) +; CHECK-NEXT: ret double [[TMP1]] ; %ltzero = fcmp nnan nsz olt double %x, 0.0 %negx = fsub double -0.0, %x @@ -323,12 +329,10 @@ define double @select_fcmp_nsz_olt_zero(double %x) { ; X < -0.0 ? -X : X --> fabs(X) -define float @select_fcmp_nsz_olt_negzero(float %x) { -; CHECK-LABEL: @select_fcmp_nsz_olt_negzero( -; CHECK-NEXT: [[LTZERO:%.*]] = fcmp nnan ninf nsz olt float [[X:%.*]], -0.000000e+00 -; CHECK-NEXT: [[NEGX:%.*]] = fsub float -0.000000e+00, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[LTZERO]], float [[NEGX]], float [[X]] -; CHECK-NEXT: ret float [[FABS]] +define float @select_fcmp_nnan_nsz_olt_negzero(float %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_olt_negzero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan ninf nsz float @llvm.fabs.f32(float [[X:%.*]]) +; CHECK-NEXT: ret float [[TMP1]] ; %ltzero = fcmp nnan nsz ninf olt float %x, -0.0 %negx = fsub float -0.0, %x @@ -338,12 +342,10 @@ define float @select_fcmp_nsz_olt_negzero(float %x) { ; X <= 0.0 ? -X : X --> fabs(X) -define double @select_fcmp_nsz_ole_zero(double %x) { -; CHECK-LABEL: @select_fcmp_nsz_ole_zero( -; CHECK-NEXT: [[LEZERO:%.*]] = fcmp fast ole double [[X:%.*]], 0.000000e+00 -; CHECK-NEXT: [[NEGX:%.*]] = fsub double -0.000000e+00, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[LEZERO]], double [[NEGX]], double [[X]] -; CHECK-NEXT: ret double [[FABS]] +define double @select_fcmp_nnan_nsz_ole_zero(double %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_ole_zero( +; CHECK-NEXT: [[TMP1:%.*]] = call fast double @llvm.fabs.f64(double [[X:%.*]]) +; CHECK-NEXT: ret double [[TMP1]] ; %lezero = fcmp fast ole double %x, 0.0 %negx = fsub double -0.0, %x @@ -353,12 +355,10 @@ define double @select_fcmp_nsz_ole_zero(double %x) { ; X <= -0.0 ? -X : X --> fabs(X) -define float @select_fcmp_nsz_ole_negzero(float %x) { -; CHECK-LABEL: @select_fcmp_nsz_ole_negzero( -; CHECK-NEXT: [[LEZERO:%.*]] = fcmp nnan nsz ole float [[X:%.*]], -0.000000e+00 -; CHECK-NEXT: [[NEGX:%.*]] = fsub float -0.000000e+00, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[LEZERO]], float [[NEGX]], float [[X]] -; CHECK-NEXT: ret float [[FABS]] +define float @select_fcmp_nnan_nsz_ole_negzero(float %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_ole_negzero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz float @llvm.fabs.f32(float [[X:%.*]]) +; CHECK-NEXT: ret float [[TMP1]] ; %lezero = fcmp nnan nsz ole float %x, -0.0 %negx = fsub float -0.0, %x @@ -368,12 +368,10 @@ define float @select_fcmp_nsz_ole_negzero(float %x) { ; X > 0.0 ? X : (0.0 - X) --> fabs(X) -define <2 x float> @select_fcmp_nsz_ogt_zero(<2 x float> %x) { -; CHECK-LABEL: @select_fcmp_nsz_ogt_zero( -; CHECK-NEXT: [[GTZERO:%.*]] = fcmp nnan nsz arcp ogt <2 x float> [[X:%.*]], zeroinitializer -; CHECK-NEXT: [[NEGX:%.*]] = fsub <2 x float> <float -0.000000e+00, float -0.000000e+00>, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select <2 x i1> [[GTZERO]], <2 x float> [[X]], <2 x float> [[NEGX]] -; CHECK-NEXT: ret <2 x float> [[FABS]] +define <2 x float> @select_fcmp_nnan_nsz_ogt_zero(<2 x float> %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_ogt_zero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz arcp <2 x float> @llvm.fabs.v2f32(<2 x float> [[X:%.*]]) +; CHECK-NEXT: ret <2 x float> [[TMP1]] ; %gtzero = fcmp nnan nsz arcp ogt <2 x float> %x, zeroinitializer %negx = fsub <2 x float> <float -0.0, float -0.0>, %x @@ -383,12 +381,10 @@ define <2 x float> @select_fcmp_nsz_ogt_zero(<2 x float> %x) { ; X > -0.0 ? X : (0.0 - X) --> fabs(X) -define half @select_fcmp_nsz_ogt_negzero(half %x) { -; CHECK-LABEL: @select_fcmp_nsz_ogt_negzero( -; CHECK-NEXT: [[GTZERO:%.*]] = fcmp fast ogt half [[X:%.*]], 0xH8000 -; CHECK-NEXT: [[NEGX:%.*]] = fsub half 0xH0000, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[GTZERO]], half [[X]], half [[NEGX]] -; CHECK-NEXT: ret half [[FABS]] +define half @select_fcmp_nnan_nsz_ogt_negzero(half %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_ogt_negzero( +; CHECK-NEXT: [[TMP1:%.*]] = call fast half @llvm.fabs.f16(half [[X:%.*]]) +; CHECK-NEXT: ret half [[TMP1]] ; %gtzero = fcmp fast ogt half %x, -0.0 %negx = fsub half 0.0, %x @@ -398,12 +394,10 @@ define half @select_fcmp_nsz_ogt_negzero(half %x) { ; X > 0.0 ? X : (0.0 - X) --> fabs(X) -define <2 x double> @select_fcmp_nsz_oge_zero(<2 x double> %x) { -; CHECK-LABEL: @select_fcmp_nsz_oge_zero( -; CHECK-NEXT: [[GEZERO:%.*]] = fcmp reassoc nnan nsz oge <2 x double> [[X:%.*]], zeroinitializer -; CHECK-NEXT: [[NEGX:%.*]] = fsub <2 x double> <double -0.000000e+00, double -0.000000e+00>, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select <2 x i1> [[GEZERO]], <2 x double> [[X]], <2 x double> [[NEGX]] -; CHECK-NEXT: ret <2 x double> [[FABS]] +define <2 x double> @select_fcmp_nnan_nsz_oge_zero(<2 x double> %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_oge_zero( +; CHECK-NEXT: [[TMP1:%.*]] = call reassoc nnan nsz <2 x double> @llvm.fabs.v2f64(<2 x double> [[X:%.*]]) +; CHECK-NEXT: ret <2 x double> [[TMP1]] ; %gezero = fcmp nnan nsz reassoc oge <2 x double> %x, zeroinitializer %negx = fsub <2 x double> <double -0.0, double -0.0>, %x @@ -413,12 +407,10 @@ define <2 x double> @select_fcmp_nsz_oge_zero(<2 x double> %x) { ; X > -0.0 ? X : (0.0 - X) --> fabs(X) -define half @select_fcmp_nsz_oge_negzero(half %x) { -; CHECK-LABEL: @select_fcmp_nsz_oge_negzero( -; CHECK-NEXT: [[GEZERO:%.*]] = fcmp nnan nsz oge half [[X:%.*]], 0xH8000 -; CHECK-NEXT: [[NEGX:%.*]] = fsub half 0xH8000, [[X]] -; CHECK-NEXT: [[FABS:%.*]] = select i1 [[GEZERO]], half [[X]], half [[NEGX]] -; CHECK-NEXT: ret half [[FABS]] +define half @select_fcmp_nnan_nsz_oge_negzero(half %x) { +; CHECK-LABEL: @select_fcmp_nnan_nsz_oge_negzero( +; CHECK-NEXT: [[TMP1:%.*]] = call nnan nsz half @llvm.fabs.f16(half [[X:%.*]]) +; CHECK-NEXT: ret half [[TMP1]] ; %gezero = fcmp nnan nsz oge half %x, -0.0 %negx = fsub half -0.0, %x |
