canonicalize:
-%a + 42
into
42 - %a
previously we were emitting:
-(%a + 42)
This fixes the infinite loop in PR12338. The generated code is still not perfect, though.
Will work on that next
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158237 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index c88ceed..00f9974 100644
--- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -170,10 +170,11 @@
// -A + B --> B - A
// -A + -B --> -(A + B)
if (Value *LHSV = dyn_castNegVal(LHS)) {
- if (Value *RHSV = dyn_castNegVal(RHS)) {
- Value *NewAdd = Builder->CreateAdd(LHSV, RHSV, "sum");
- return BinaryOperator::CreateNeg(NewAdd);
- }
+ if (!isa<Constant>(RHS))
+ if (Value *RHSV = dyn_castNegVal(RHS)) {
+ Value *NewAdd = Builder->CreateAdd(LHSV, RHSV, "sum");
+ return BinaryOperator::CreateNeg(NewAdd);
+ }
return BinaryOperator::CreateSub(RHS, LHSV);
}