ConstraintElim: assert on invalid union field (NFC)

[artagnon]

getContextInst currently returns an invalid union field, when it is called with a ConditionFact, although existing callers don't do this. In order to error out early and serve as documentation for future callers, add an assert forbidding the behavior.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Ramkumar Ramachandra (artagnon)

Changes

getContextInst currently returns an invalid union field, when it is called with a ConditionFact, although existing callers don't do this. In order to error out early and serve as documentation for future callers, add an assert forbidding the behavior.

---

Full diff: https://github.com/llvm/llvm-project/pull/115898.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Scalar/ConstraintElimination.cpp (+1)

diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 7c06e0c757e1cc..d2e532d29d07b5 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -164,6 +164,7 @@ struct FactOrCheck {
   }
 
   Instruction *getContextInst() const {
+    assert(!isConditionFact());
     if (Ty == EntryTy::UseCheck)
       return getContextInstForUse(*U);
     return Inst;

[nikic]

LGTM

[fhahn]

Thanks for adding the assert!