[IR] add optional parameter for copying IR flags to compare instructions
As shown, this is used to eliminate redundant code in InstCombine,
and there are more cases where we should be using this pattern, but
we're currently unintentionally dropping flags.
llvm-svn: 346282
diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index 3b8d8d0..7d4b6df 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -3149,15 +3149,18 @@
//===----------------------------------------------------------------------===//
CmpInst::CmpInst(Type *ty, OtherOps op, Predicate predicate, Value *LHS,
- Value *RHS, const Twine &Name, Instruction *InsertBefore)
+ Value *RHS, const Twine &Name, Instruction *InsertBefore,
+ Instruction *FlagsSource)
: Instruction(ty, op,
OperandTraits<CmpInst>::op_begin(this),
OperandTraits<CmpInst>::operands(this),
InsertBefore) {
- Op<0>() = LHS;
- Op<1>() = RHS;
+ Op<0>() = LHS;
+ Op<1>() = RHS;
setPredicate((Predicate)predicate);
setName(Name);
+ if (FlagsSource)
+ copyIRFlags(FlagsSource);
}
CmpInst::CmpInst(Type *ty, OtherOps op, Predicate predicate, Value *LHS,