[PATCH] D114633: [SCEV] Turn validity check in getExistingSCEV into assert (NFC).

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: nikic, reames, mkazantsev.
Herald added subscribers: javed.absar, hiraditya.
fhahn requested review of this revision.
Herald added a project: LLVM.

Now that we track users of SCEV expressions, we should be able to always
invalidate containing expressions.

With that, I think the case where a value gets removed but
SCEVs containing references to it should not be possible any longer.
Turn check into an assert.

This slightly reduces compile-time:

NewPM-O3: -0.27%
NewPM-ReleaseThinLTO: -0.21%
NewPM-ReleaseLTO-g: -0.26%

http://llvm-compile-time-tracker.com/compare.php?from=c3dc6b081da6ba503e67d260033f81f61eb38ea3&to=95a4a028b1f1dd0bc3d221435953b7d2c031b3d5&stat=instructions


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D114633

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp


Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -4134,10 +4134,9 @@
   ValueExprMapType::iterator I = ValueExprMap.find_as(V);
   if (I != ValueExprMap.end()) {
     const SCEV *S = I->second;
-    if (checkValidity(S))
-      return S;
-    eraseValueFromMap(V);
-    forgetMemoizedResults(S);
+    assert(checkValidity(S) &&
+           "existing SCEV has not been properly invalidated");
+    return S;
   }
   return nullptr;
 }


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