[PATCH] D137027: [llvm] Improve performance of programUndefinedIfUndefOrPoison

[Nikita Popov via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rGd5e59e99f404: [ValueTracking] Improve performance of programUndefinedIfUndefOrPoison (NFC) (authored by gezalore, committed by nikic).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D137027/new/

https://reviews.llvm.org/D137027

Files:
  llvm/lib/Analysis/ValueTracking.cpp


Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -5722,11 +5722,6 @@
   SmallSet<const BasicBlock *, 4> Visited;
 
   YieldsPoison.insert(V);
-  auto Propagate = [&](const User *User) {
-    if (propagatesPoison(cast<Operator>(User)))
-      YieldsPoison.insert(User);
-  };
-  for_each(V->users(), Propagate);
   Visited.insert(BB);
 
   while (true) {
@@ -5740,9 +5735,16 @@
       if (!isGuaranteedToTransferExecutionToSuccessor(&I))
         return false;
 
-      // Mark poison that propagates from I through uses of I.
-      if (YieldsPoison.count(&I))
-        for_each(I.users(), Propagate);
+      // If this instruction propagates poison, mark it as poison if any of
+      // its operands are poison
+      if (propagatesPoison(cast<Operator>(&I))) {
+        for (const Value *Op : I.operands()) {
+          if (YieldsPoison.count(Op)) {
+            YieldsPoison.insert(&I);
+            break;
+          }
+        }
+      }
     }
 
     BB = BB->getSingleSuccessor();


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