Index: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2929,10 +2929,8 @@
   // 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.
   // (X <= +/-0.0) ? (0.0 - X) : X --> fabs(X)
-  Instruction *FSub;
   if (match(CondVal, m_FCmp(Pred, m_Specific(FalseVal), m_AnyZeroFP())) &&
       match(TrueVal, m_FSub(m_PosZeroFP(), m_Specific(FalseVal))) &&
-      match(TrueVal, m_Instruction(FSub)) &&
       (Pred == FCmpInst::FCMP_OLE || Pred == FCmpInst::FCMP_ULE)) {
     Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, FalseVal, &SI);
     return replaceInstUsesWith(SI, Fabs);
@@ -2940,35 +2938,62 @@
   // (X >  +/-0.0) ? X : (0.0 - X) --> fabs(X)
   if (match(CondVal, m_FCmp(Pred, m_Specific(TrueVal), m_AnyZeroFP())) &&
       match(FalseVal, m_FSub(m_PosZeroFP(), m_Specific(TrueVal))) &&
-      match(FalseVal, m_Instruction(FSub)) &&
       (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_UGT)) {
     Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
     return replaceInstUsesWith(SI, Fabs);
   }
-  // With nnan and nsz:
+  // (X < +/-0.0) ? X : (0.0 - X) --> (0.0 - fabs(X))
+  // With nsz:
+  // (X < +/-0.0) ? X : -X --> -fabs(X)
+  if (match(CondVal, m_FCmp(Pred, m_Specific(TrueVal), m_AnyZeroFP())) &&
+      (match(FalseVal, m_FSub(m_PosZeroFP(), m_Specific(TrueVal))) ||
+       (match(FalseVal, m_FNeg(m_Specific(TrueVal))) &&
+        cast<Instruction>(FalseVal)->hasNoSignedZeros())) &&
+      (Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_ULT)) {
+    Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
+    return BinaryOperator::CreateFSubFMF(ConstantFP::get(Fabs->getType(), 0.0),
+                                         Fabs, cast<Instruction>(FalseVal));
+  }
+  // With nsz:
   // (X <  +/-0.0) ? -X : X --> fabs(X)
   // (X <= +/-0.0) ? -X : X --> fabs(X)
-  Instruction *FNeg;
   if (match(CondVal, m_FCmp(Pred, m_Specific(FalseVal), m_AnyZeroFP())) &&
-      match(TrueVal, m_FNeg(m_Specific(FalseVal))) &&
-      match(TrueVal, m_Instruction(FNeg)) && SI.hasNoSignedZeros() &&
+      match(TrueVal, m_FNeg(m_Specific(FalseVal))) && SI.hasNoSignedZeros() &&
       (Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_OLE ||
        Pred == FCmpInst::FCMP_ULT || Pred == FCmpInst::FCMP_ULE)) {
     Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, FalseVal, &SI);
     return replaceInstUsesWith(SI, Fabs);
   }
-  // With nnan and nsz:
+  // With nsz:
   // (X >  +/-0.0) ? X : -X --> fabs(X)
   // (X >= +/-0.0) ? X : -X --> fabs(X)
   if (match(CondVal, m_FCmp(Pred, m_Specific(TrueVal), m_AnyZeroFP())) &&
-      match(FalseVal, m_FNeg(m_Specific(TrueVal))) &&
-      match(FalseVal, m_Instruction(FNeg)) && SI.hasNoSignedZeros() &&
+      match(FalseVal, m_FNeg(m_Specific(TrueVal))) && SI.hasNoSignedZeros() &&
       (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_OGE ||
        Pred == FCmpInst::FCMP_UGT || Pred == FCmpInst::FCMP_UGE)) {
     Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
     return replaceInstUsesWith(SI, Fabs);
   }
-
+  // With nsz:
+  // (X <  +/-0.0) ? X : -X --> -fabs(X)
+  // (X <= +/-0.0) ? X : -X --> -fabs(X)
+  if (match(CondVal, m_FCmp(Pred, m_Specific(TrueVal), m_AnyZeroFP())) &&
+      match(FalseVal, m_FNeg(m_Specific(TrueVal))) && SI.hasNoSignedZeros() &&
+      (Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_OLE ||
+       Pred == FCmpInst::FCMP_ULT || Pred == FCmpInst::FCMP_ULE)) {
+    Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
+    return UnaryOperator::CreateFNegFMF(Fabs, cast<Instruction>(FalseVal));
+  }
+  // With nsz:
+  // (X >  +/-0.0) ? -X : X --> -fabs(X)
+  // (X >= +/-0.0) ? -X : X --> -fabs(X)
+  if (match(CondVal, m_FCmp(Pred, m_Specific(FalseVal), m_AnyZeroFP())) &&
+      match(TrueVal, m_FNeg(m_Specific(FalseVal))) && SI.hasNoSignedZeros() &&
+      (Pred == FCmpInst::FCMP_OGT || Pred == FCmpInst::FCMP_OGE ||
+       Pred == FCmpInst::FCMP_UGT || Pred == FCmpInst::FCMP_UGE)) {
+    Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, FalseVal, &SI);
+    return UnaryOperator::CreateFNegFMF(Fabs, cast<Instruction>(TrueVal));
+  }
   // See if we are selecting two values based on a comparison of the two values.
   if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
     if (Instruction *Result = foldSelectInstWithICmp(SI, ICI))
Index: llvm/test/Transforms/InstCombine/fabs.ll
===================================================================
--- llvm/test/Transforms/InstCombine/fabs.ll
+++ llvm/test/Transforms/InstCombine/fabs.ll
@@ -975,3 +975,225 @@
   %fabs = call <2 x float> @llvm.fabs.v2f32(<2 x float> %s)
   ret <2 x float> %fabs
 }
+
+; (X <  +/-0.0) ? X : -X --> -fabs(X)
+; (X <= +/-0.0) ? X : -X --> -fabs(X)
+; One negative test with no fmf
+define double @select_noFMF_nfabs_lt(double %x) {
+; CHECK-LABEL: @select_noFMF_nfabs_lt(
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp olt double [[X:%.*]], 0.000000e+00
+; CHECK-NEXT:    [[NEGX:%.*]] = fneg double [[X]]
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], double [[X]], double [[NEGX]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp olt double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select i1 %cmp, double %x, double %negX
+  ret double %sel
+}
+
+; One test where the neg has fmfs.
+define double @select_nsz_nfabs_lt_fmfProp(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_lt_fmfProp(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg fast double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp olt double %x, 0.000000e+00
+  %negX = fneg fast double %x
+  %sel = select nsz i1 %cmp, double %x, double %negX
+  ret double %sel
+}
+
+; Tests with various predicate types.
+define double @select_nsz_nfabs_olt(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_olt(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp olt double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %x, double %negX
+  ret double %sel
+}
+
+define double @select_nsz_nfabs_ult(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_ult(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp ult double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %x, double %negX
+  ret double %sel
+}
+
+define double @select_nsz_nfabs_ole(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_ole(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp ole double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %x, double %negX
+  ret double %sel
+}
+
+define double @select_nsz_nfabs_ule(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_ule(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp ule double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %x, double %negX
+  ret double %sel
+}
+
+; (X >  +/-0.0) ? -X : X --> -fabs(X)
+; (X >= +/-0.0) ? -X : X --> -fabs(X)
+; One negative test with no fmf
+define double @select_noFMF_nfabs_gt(double %x) {
+; CHECK-LABEL: @select_noFMF_nfabs_gt(
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ogt double [[X:%.*]], 0.000000e+00
+; CHECK-NEXT:    [[NEGX:%.*]] = fneg double [[X]]
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP]], double [[NEGX]], double [[X]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp ogt double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select i1 %cmp, double %negX, double %x
+  ret double %sel
+}
+
+; One test where the neg has fmfs.
+define double @select_nsz_nfabs_gt_fmfProp(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_gt_fmfProp(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg fast double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp ogt double %x, 0.000000e+00
+  %negX = fneg fast double %x
+  %sel = select nsz i1 %cmp, double %negX, double %x
+  ret double %sel
+}
+
+; Tests with various predicate types.
+define double @select_nsz_nfabs_ogt(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_ogt(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp ogt double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %negX, double %x
+  ret double %sel
+}
+
+define double @select_nsz_nfabs_ugt(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_ugt(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp ugt double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %negX, double %x
+  ret double %sel
+}
+
+define double @select_nsz_nfabs_oge(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_oge(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp oge double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %negX, double %x
+  ret double %sel
+}
+
+define double @select_nsz_nfabs_uge(double %x) {
+; CHECK-LABEL: @select_nsz_nfabs_uge(
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[SEL:%.*]] = fneg double [[TMP1]]
+; CHECK-NEXT:    ret double [[SEL]]
+;
+  %cmp = fcmp uge double %x, 0.000000e+00
+  %negX = fneg double %x
+  %sel = select nsz i1 %cmp, double %negX, double %x
+  ret double %sel
+}
+
+; (X < +/-0.0) ? X : (0.0 - X) --> (0.0 - fabs(X))
+; One negative test with <=.
+define double @select_noFMF_fsubfabs_le(double %x) {
+; CHECK-LABEL: @select_noFMF_fsubfabs_le(
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ole double [[X:%.*]], 0.000000e+00
+; CHECK-NEXT:    [[SUB:%.*]] = fsub double 0.000000e+00, [[X]]
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = select i1 [[CMP]], double [[X]], double [[SUB]]
+; CHECK-NEXT:    ret double [[RETVAL_0]]
+;
+  %cmp = fcmp ole double %x, 0.000000e+00
+  %sub = fsub double 0.000000e+00, %x
+  %retval.0 = select i1 %cmp, double %x, double %sub
+  ret double %retval.0
+}
+
+define double @select_noFMF_fsubfabs_olt(double %x) {
+; CHECK-LABEL: @select_noFMF_fsubfabs_olt(
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = fsub double 0.000000e+00, [[TMP1]]
+; CHECK-NEXT:    ret double [[RETVAL_0]]
+;
+  %cmp = fcmp olt double %x, 0.000000e+00
+  %sub = fsub double 0.000000e+00, %x
+  %retval.0 = select i1 %cmp, double %x, double %sub
+  ret double %retval.0
+}
+
+define double @select_noFMF_fsubfabs_ult(double %x) {
+; CHECK-LABEL: @select_noFMF_fsubfabs_ult(
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = fsub double 0.000000e+00, [[TMP1]]
+; CHECK-NEXT:    ret double [[RETVAL_0]]
+;
+  %cmp = fcmp ult double %x, 0.000000e+00
+  %sub = fsub double 0.000000e+00, %x
+  %retval.0 = select i1 %cmp, double %x, double %sub
+  ret double %retval.0
+}
+
+
+; With nsz:
+; (X < +/-0.0) ? X : -X --> -fabs(X)
+define double @select_nsz_fnegfabs_olt(double %x) {
+; CHECK-LABEL: @select_nsz_fnegfabs_olt(
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = fneg nsz double [[TMP1]]
+; CHECK-NEXT:    ret double [[RETVAL_0]]
+;
+  %cmp = fcmp olt double %x, 0.000000e+00
+  %negX = fneg nsz double %x
+  %retval.0 = select i1 %cmp, double %x, double %negX
+  ret double %retval.0
+}
+
+define double @select_nsz_fnegfabs_ult(double %x) {
+; CHECK-LABEL: @select_nsz_fnegfabs_ult(
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL_0:%.*]] = fneg nsz double [[TMP1]]
+; CHECK-NEXT:    ret double [[RETVAL_0]]
+;
+  %cmp = fcmp ult double %x, 0.000000e+00
+  %negX = fneg nsz double %x
+  %retval.0 = select i1 %cmp, double %x, double %negX
+  ret double %retval.0
+}