diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -273,6 +273,7 @@
   bool visitCmpInst(CmpInst &I);
   bool visitSub(BinaryOperator &I);
   bool visitBinaryOperator(BinaryOperator &I);
+  bool visitFNeg(UnaryOperator &I);
   bool visitLoad(LoadInst &I);
   bool visitStore(StoreInst &I);
   bool visitExtractValue(ExtractValueInst &I);
@@ -1106,6 +1107,28 @@
   return false;
 }
 
+bool CallAnalyzer::visitFNeg(UnaryOperator &I) {
+  Value *Op = I.getOperand(0);
+  Constant *COp = dyn_cast<Constant>(Op);
+  if (!COp)
+    COp = SimplifiedValues.lookup(Op);
+
+  Value *SimpleV = SimplifyFNegInst(COp ? COp : Op,
+                                    cast<FPMathOperator>(I).getFastMathFlags(),
+                                    DL);
+
+  if (Constant *C = dyn_cast_or_null<Constant>(SimpleV))
+    SimplifiedValues[&I] = C;
+
+  if (SimpleV)
+    return true;
+
+  // Disable any SROA on arguments to arbitrary, unsimplified fneg.
+  disableSROA(Op);
+
+  return false;
+}
+
 bool CallAnalyzer::visitLoad(LoadInst &I) {
   Value *SROAArg;
   DenseMap<Value *, int>::iterator CostIt;