Index: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2962,6 +2962,24 @@
     Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
     return replaceInstUsesWith(SI, Fabs);
   }
+  // Negative Fabs:
+  // 1. (X < +/-0.0) ? X : (0.0 - X)  --> (0.0 - fabs(X))
+  // 2. nsz on the sub (canonicalized to FNeg) or on the select:
+  //    (X < +/-0.0) ? X : -X         --> -X
+  if (match(CondVal, m_FCmp(Pred, m_Specific(TrueVal), m_AnyZeroFP())) &&
+      (Pred == FCmpInst::FCMP_OLT || Pred == FCmpInst::FCMP_ULT)) {
+    if (match(FalseVal, m_FSub(m_PosZeroFP(), m_Specific(TrueVal)))) {
+      Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
+      return BinaryOperator::CreateFSubFMF(
+          ConstantFP::get(Fabs->getType(), 0.0), Fabs,
+          cast<Instruction>(FalseVal));
+    } else if (match(FalseVal, m_FNeg(m_Specific(TrueVal))) &&
+               (cast<Instruction>(FalseVal)->hasNoSignedZeros() ||
+                SI.hasNoSignedZeros())) {
+      Value *Fabs = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, TrueVal, &SI);
+      return UnaryOperator::CreateFNegFMF(Fabs, cast<Instruction>(FalseVal));
+    }
+  }
 
   // See if we are selecting two values based on a comparison of the two values.
   if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal))
Index: llvm/test/Transforms/InstCombine/fneg-fabs.ll
===================================================================
--- llvm/test/Transforms/InstCombine/fneg-fabs.ll
+++ llvm/test/Transforms/InstCombine/fneg-fabs.ll
@@ -10,9 +10,8 @@
 ; (X < +/-0.0) ? X : (0.0 - X)  --> (0.0 - fabs(X))
 define double @olt_fsub(double %x) {
 ; CHECK-LABEL: @olt_fsub(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp olt double [[X:%.*]], 0.000000e+00
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub double 0.000000e+00, [[X]]
-; CHECK-NEXT:    [[RETVAL:%.*]] = select i1 [[CMP]], double [[X]], double [[NEGX]]
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL:%.*]] = fsub double 0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    ret double [[RETVAL]]
 ;
   %cmp = fcmp olt double %x, 0.000000e+00
@@ -22,9 +21,8 @@
 }
 define double @ult_fsub(double %x) {
 ; CHECK-LABEL: @ult_fsub(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp ult double [[X:%.*]], 0.000000e+00
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub double 0.000000e+00, [[X]]
-; CHECK-NEXT:    [[RETVAL:%.*]] = select i1 [[CMP]], double [[X]], double [[NEGX]]
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL:%.*]] = fsub double 0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    ret double [[RETVAL]]
 ;
   %cmp = fcmp ult double %x, 0.000000e+00
@@ -100,9 +98,8 @@
 
 define double @ult_fneg1(double %x) {
 ; CHECK-LABEL: @ult_fneg1(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp ult double [[X:%.*]], 0.000000e+00
-; CHECK-NEXT:    [[NEGX:%.*]] = fneg nsz double [[X]]
-; CHECK-NEXT:    [[RETVAL:%.*]] = select i1 [[CMP]], double [[X]], double [[NEGX]]
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL:%.*]] = fneg nsz double [[TMP1]]
 ; CHECK-NEXT:    ret double [[RETVAL]]
 ;
   %cmp = fcmp ult double %x, 0.000000e+00
@@ -112,9 +109,8 @@
 }
 define double @ult_fneg2(double %x) {
 ; CHECK-LABEL: @ult_fneg2(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp ult double [[X:%.*]], 0.000000e+00
-; CHECK-NEXT:    [[NEGX:%.*]] = fneg double [[X]]
-; CHECK-NEXT:    [[RETVAL:%.*]] = select nsz i1 [[CMP]], double [[X]], double [[NEGX]]
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL:%.*]] = fneg double [[TMP1]]
 ; CHECK-NEXT:    ret double [[RETVAL]]
 ;
   %cmp = fcmp ult double %x, 0.000000e+00
@@ -124,9 +120,8 @@
 }
 define double @olt_fneg1(double %x) {
 ; CHECK-LABEL: @olt_fneg1(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp olt double [[X:%.*]], 0.000000e+00
-; CHECK-NEXT:    [[NEGX:%.*]] = fneg nsz double [[X]]
-; CHECK-NEXT:    [[RETVAL:%.*]] = select i1 [[CMP]], double [[X]], double [[NEGX]]
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL:%.*]] = fneg nsz double [[TMP1]]
 ; CHECK-NEXT:    ret double [[RETVAL]]
 ;
   %cmp = fcmp olt double %x, 0.000000e+00
@@ -136,9 +131,8 @@
 }
 define double @olt_fneg2(double %x) {
 ; CHECK-LABEL: @olt_fneg2(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp olt double [[X:%.*]], 0.000000e+00
-; CHECK-NEXT:    [[NEGX:%.*]] = fneg double [[X]]
-; CHECK-NEXT:    [[RETVAL:%.*]] = select nsz i1 [[CMP]], double [[X]], double [[NEGX]]
+; CHECK-NEXT:    [[TMP1:%.*]] = call nsz double @llvm.fabs.f64(double [[X:%.*]])
+; CHECK-NEXT:    [[RETVAL:%.*]] = fneg double [[TMP1]]
 ; CHECK-NEXT:    ret double [[RETVAL]]
 ;
   %cmp = fcmp olt double %x, 0.000000e+00