[PATCH] D86835: [Attributor][NFC] Do not manifest noundef for positions to be changed to undef

[Shinji Okumura via Phabricator via llvm-commits]

okura created this revision.
Herald added subscribers: llvm-commits, kuter, danielkiss, uenoku, hiraditya.
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okura requested review of this revision.
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This patch fixes AANoUndef manifestation.
We should not manifest noundef for positions that will be changed to undef.


https://reviews.llvm.org/D86835

Files:
  llvm/lib/Transforms/IPO/AttributorAttributes.cpp


Index: llvm/lib/Transforms/IPO/AttributorAttributes.cpp
===================================================================
--- llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -7812,6 +7812,13 @@
     // values.
     if (A.isAssumedDead(getIRPosition(), nullptr, nullptr))
       return ChangeStatus::UNCHANGED;
+    // A position whose simplified value does not have any value is
+    // considered to be dead. We don't manifest noundef in such positions for
+    // the same reason above.
+    auto &ValueSimplifyAA = A.getAAFor<AAValueSimplify>(
+        *this, getIRPosition(), /* TrackDependence */ false);
+    if (!ValueSimplifyAA.getAssumedSimplifiedValue(A).hasValue())
+      return ChangeStatus::UNCHANGED;
     return AANoUndef::manifest(A);
   }
 };


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