[PATCH] D111180: The result of a function with noundef return attribute must be well defined

[Philip Reames via Phabricator via llvm-commits]

reames created this revision.
reames added reviewers: nlopes, aqjune.
Herald added subscribers: javed.absar, bollu, hiraditya, mcrosier.
reames requested review of this revision.
Herald added a project: LLVM.

This does for readability of returns within said function as what we do for the caller side when reasoning about what might be poison.

Couldn't figure out a small test.  I'm working on this from SCEV, but that's blocked by other things as well.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D111180

Files:
  llvm/lib/Analysis/ValueTracking.cpp


Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -5418,7 +5418,10 @@
       }
       break;
     }
-
+    case Instruction::Ret:
+      if (I->getFunction()->hasRetAttribute(Attribute::NoUndef))
+        Operands.insert(I->getOperand(0));
+      break;
     default:
       break;
   }


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