Index: include/llvm/Target/TargetLowering.h
===================================================================
--- include/llvm/Target/TargetLowering.h	(revision 215148)
+++ include/llvm/Target/TargetLowering.h	(working copy)
@@ -261,6 +261,11 @@
   bool isMaskAndBranchFoldingLegal() const {
     return MaskAndBranchFoldingIsLegal;
   }
+  
+  /// Return true if target supports floating point exceptions.
+  bool hasFloatingPointExceptions() const {
+    return FloatingPointExceptions;
+  }
 
   /// Return the ValueType of the result of SETCC operations.  Also used to
   /// obtain the target's preferred type for the condition operand of SELECT and
@@ -1053,6 +1058,12 @@
   /// possible, should be replaced by an alternate sequence of instructions not
   /// containing an integer divide.
   void setIntDivIsCheap(bool isCheap = true) { IntDivIsCheap = isCheap; }
+  
+  /// Tells the code generator that this target supports floating point
+  /// exceptions and cares about preserving floating point exception behavior.
+  void setHasFloatingPointExceptions(bool FPExceptions = true) {
+    FloatingPointExceptions = FPExceptions;
+  }
 
   /// Tells the code generator which bitwidths to bypass.
   void addBypassSlowDiv(unsigned int SlowBitWidth, unsigned int FastBitWidth) {
Index: lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/SelectionDAG.cpp	(revision 215148)
+++ lib/CodeGen/SelectionDAG/SelectionDAG.cpp	(working copy)
@@ -3402,6 +3402,7 @@
   }
 
   // Constant fold FP operations.
+  bool HasFPExceptions = TLI->hasFloatingPointExceptions();
   ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1.getNode());
   ConstantFPSDNode *N2CFP = dyn_cast<ConstantFPSDNode>(N2.getNode());
   if (N1CFP) {
@@ -3415,28 +3416,32 @@
       switch (Opcode) {
       case ISD::FADD:
         s = V1.add(V2, APFloat::rmNearestTiesToEven);
-        if (s != APFloat::opInvalidOp)
+        if (!HasFPExceptions || s != APFloat::opInvalidOp)
           return getConstantFP(V1, VT);
         break;
       case ISD::FSUB:
         s = V1.subtract(V2, APFloat::rmNearestTiesToEven);
-        if (s!=APFloat::opInvalidOp)
+        if (!HasFPExceptions || s!=APFloat::opInvalidOp)
           return getConstantFP(V1, VT);
         break;
       case ISD::FMUL:
         s = V1.multiply(V2, APFloat::rmNearestTiesToEven);
-        if (s!=APFloat::opInvalidOp)
+        if (!HasFPExceptions || s!=APFloat::opInvalidOp)
           return getConstantFP(V1, VT);
         break;
       case ISD::FDIV:
         s = V1.divide(V2, APFloat::rmNearestTiesToEven);
-        if (s!=APFloat::opInvalidOp && s!=APFloat::opDivByZero)
+        if (!HasFPExceptions || (s!=APFloat::opInvalidOp &&
+                                 s!=APFloat::opDivByZero)) {
           return getConstantFP(V1, VT);
+        }
         break;
       case ISD::FREM :
         s = V1.mod(V2, APFloat::rmNearestTiesToEven);
-        if (s!=APFloat::opInvalidOp && s!=APFloat::opDivByZero)
+        if (!HasFPExceptions || (s!=APFloat::opInvalidOp &&
+                                 s!=APFloat::opDivByZero)) {
           return getConstantFP(V1, VT);
+        }
         break;
       case ISD::FCOPYSIGN:
         V1.copySign(V2);
Index: lib/CodeGen/TargetLoweringBase.cpp
===================================================================
--- lib/CodeGen/TargetLoweringBase.cpp	(revision 215148)
+++ lib/CodeGen/TargetLoweringBase.cpp	(working copy)
@@ -705,6 +705,7 @@
   JumpIsExpensive = false;
   PredictableSelectIsExpensive = false;
   MaskAndBranchFoldingIsLegal = false;
+  FloatingPointExceptions = true;
   StackPointerRegisterToSaveRestore = 0;
   ExceptionPointerRegister = 0;
   ExceptionSelectorRegister = 0;