[PATCH] add a convenience method to copy wrapping, exact, and fast-math flags (NFC)

[David Majnemer]

================
Comment at: lib/IR/Instructions.cpp:2033-2049
@@ -2032,1 +2032,19 @@
 
+void BinaryOperator::copyFlags(const Value *V) {
+  // Copy the wrapping flags.
+  const OverflowingBinaryOperator *OB = dyn_cast<OverflowingBinaryOperator>(V);
+  if (OB) {
+    setHasNoSignedWrap(OB->hasNoSignedWrap());
+    setHasNoUnsignedWrap(OB->hasNoUnsignedWrap());
+  }
+  // Copy the exact flag.
+  const PossiblyExactOperator *PE = dyn_cast<PossiblyExactOperator>(V);
+  if (PE)
+    setIsExact(PE->isExact());
+  
+  // Copy the fast-math flags.
+  const FPMathOperator *FP = dyn_cast<FPMathOperator>(V);
+  if (FP)
+    setFastMathFlags(FP->getFastMathFlags());
+}
+
----------------
You could shorten this a bit by doing two things:
  # Folding the dyn_cast into the if
  # Using auto for the type of the variables, the dyn_cast makes unambiguous.

================
Comment at: test/Transforms/LoopVectorize/exact.ll:3-4
@@ +2,4 @@
+
+;CHECK-LABEL: @lshr_exact(
+;CHECK: lshr exact <4 x i32>
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
----------------
Space between ; and CHECK.

http://reviews.llvm.org/D5138