Index: include/llvm/IR/IRBuilder.h
===================================================================
--- include/llvm/IR/IRBuilder.h
+++ include/llvm/IR/IRBuilder.h
@@ -785,7 +785,9 @@
                     MDNode *FPMathTag = nullptr) {
     if (Constant *LC = dyn_cast<Constant>(LHS))
       if (Constant *RC = dyn_cast<Constant>(RHS))
-        return Insert(Folder.CreateFAdd(LC, RC, FMF), Name);
+        if (Constant *C = Insert(Folder.CreateFAdd(LC, RC, FMF,
+                                                   /* Strict = */ true), Name))
+          return C;
     return Insert(AddFPMathAttributes(BinaryOperator::CreateFAdd(LHS, RHS),
                                       FPMathTag, FMF), Name);
   }
@@ -807,7 +809,9 @@
                     MDNode *FPMathTag = nullptr) {
     if (Constant *LC = dyn_cast<Constant>(LHS))
       if (Constant *RC = dyn_cast<Constant>(RHS))
-        return Insert(Folder.CreateFSub(LC, RC, FMF), Name);
+        if (Constant *C = Insert(Folder.CreateFSub(LC, RC, FMF,
+                                                   /* Strict = */ true), Name))
+          return C;
     return Insert(AddFPMathAttributes(BinaryOperator::CreateFSub(LHS, RHS),
                                       FPMathTag, FMF), Name);
   }
@@ -829,7 +833,9 @@
                     MDNode *FPMathTag = nullptr) {
     if (Constant *LC = dyn_cast<Constant>(LHS))
       if (Constant *RC = dyn_cast<Constant>(RHS))
-        return Insert(Folder.CreateFMul(LC, RC, FMF), Name);
+        if (Constant *C = Insert(Folder.CreateFMul(LC, RC, FMF,
+                                                   /* Strict = */ true), Name))
+          return C;
     return Insert(AddFPMathAttributes(BinaryOperator::CreateFMul(LHS, RHS),
                                       FPMathTag, FMF), Name);
   }
@@ -861,7 +867,9 @@
                     MDNode *FPMathTag = nullptr) {
     if (Constant *LC = dyn_cast<Constant>(LHS))
       if (Constant *RC = dyn_cast<Constant>(RHS))
-        return Insert(Folder.CreateFDiv(LC, RC, FMF), Name);
+        if (Constant *C = Insert(Folder.CreateFDiv(LC, RC, FMF,
+                                                   /* Strict = */ true), Name))
+          return C;
     return Insert(AddFPMathAttributes(BinaryOperator::CreateFDiv(LHS, RHS),
                                       FPMathTag, FMF), Name);
   }
@@ -881,7 +889,9 @@
                     MDNode *FPMathTag = nullptr) {
     if (Constant *LC = dyn_cast<Constant>(LHS))
       if (Constant *RC = dyn_cast<Constant>(RHS))
-        return Insert(Folder.CreateFRem(LC, RC, FMF), Name);
+        if (Constant *C = Insert(Folder.CreateFRem(LC, RC, FMF,
+                                                   /* Strict = */ true), Name))
+          return C;
     return Insert(AddFPMathAttributes(BinaryOperator::CreateFRem(LHS, RHS),
                                       FPMathTag, FMF), Name);
   }
Index: unittests/IR/IRBuilderTest.cpp
===================================================================
--- unittests/IR/IRBuilderTest.cpp
+++ unittests/IR/IRBuilderTest.cpp
@@ -221,6 +221,54 @@
 
 }
 
+TEST_F(IRBuilderTest, FPEnvFlags) {
+  IRBuilder<> Builder(BB);
+  Value *F;
+
+  Constant *Huge = ConstantFP::get(Type::getDoubleTy(Ctx), 1.000000e+308);
+  Constant *Big = ConstantFP::get(Type::getDoubleTy(Ctx), 1.000000e+300);
+  Constant *Small = ConstantFP::get(Type::getDoubleTy(Ctx), 1.000000e-300);
+  Constant *Tiny = ConstantFP::get(Type::getDoubleTy(Ctx), 1.000000e-308);
+  Constant *Zero = ConstantFP::get(Type::getDoubleTy(Ctx), 0.0);
+
+  FastMathFlags KeepExceptions;
+  KeepExceptions.clear();
+  KeepExceptions.setNoRounding();
+  Builder.SetFastMathFlags(KeepExceptions);
+
+  F = Builder.CreateFAdd(Huge, Huge);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  F = Builder.CreateFSub(Tiny, Huge);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  F = Builder.CreateFMul(Big, Big);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  F = Builder.CreateFDiv(Big, Small);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  F = Builder.CreateFDiv(Big, Zero);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  F = Builder.CreateFRem(Big, Zero);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  FastMathFlags KeepRounding;
+  KeepRounding.clear();
+  KeepRounding.setNoExceptions();
+  Builder.SetFastMathFlags(KeepRounding);
+
+  F = Builder.CreateFAdd(Huge, Huge);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  F = Builder.CreateFSub(Tiny, Huge);
+  EXPECT_FALSE(isa<Constant>(F));
+
+  F = Builder.CreateFMul(Huge, Huge);
+  EXPECT_FALSE(isa<Constant>(F));
+}
+
 TEST_F(IRBuilderTest, WrapFlags) {
   IRBuilder<true, NoFolder> Builder(BB);