[llvm] [JumpThreading] Infer constants from correlated PHIs (PR #190184)

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``````````bash
git-clang-format --diff origin/main HEAD --extensions cpp -- llvm/lib/Transforms/Scalar/JumpThreading.cpp --diff_from_common_commit
``````````

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``````````diff
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index 9712fb716..47d7626aa 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -591,14 +591,14 @@ getIncomingBlockConditionValue(Value *Cond, PHINode *GuardPN,
   if (CmpPN != GuardPN)
     return std::nullopt;
 
-  Value *LHS = GuardOnLHS ? GuardPN->getIncomingValue(IncomingIdx)
-                          : Cmp->getOperand(0)->DoPHITranslation(PhiBB,
-                                                                  IncomingBB);
-  Value *RHS = GuardOnLHS ? Cmp->getOperand(1)->DoPHITranslation(PhiBB,
-                                                                 IncomingBB)
-                          : GuardPN->getIncomingValue(IncomingIdx);
-  if (auto *C = dyn_cast_or_null<ConstantInt>(
-          simplifyCmpInst(Cmp->getPredicate(), LHS, RHS, {PhiBB->getDataLayout()})))
+  Value *LHS = GuardOnLHS
+                   ? GuardPN->getIncomingValue(IncomingIdx)
+                   : Cmp->getOperand(0)->DoPHITranslation(PhiBB, IncomingBB);
+  Value *RHS = GuardOnLHS
+                   ? Cmp->getOperand(1)->DoPHITranslation(PhiBB, IncomingBB)
+                   : GuardPN->getIncomingValue(IncomingIdx);
+  if (auto *C = dyn_cast_or_null<ConstantInt>(simplifyCmpInst(
+          Cmp->getPredicate(), LHS, RHS, {PhiBB->getDataLayout()})))
     return !C->isZero();
   return std::nullopt;
 }
@@ -607,11 +607,9 @@ getIncomingBlockConditionValue(Value *Cond, PHINode *GuardPN,
 /// the same block that controls the branch in FromBB. If the branch condition
 /// makes exactly one incoming block feasible, use the corresponding incoming
 /// value of V.
-static Constant *
-getKnownConstantFromCorrelatedPHI(Value *V, BasicBlock *FromBB,
-                                  BasicBlock *ToBB,
-                                  ConstantPreference Preference,
-                                  LazyValueInfo *LVI) {
+static Constant *getKnownConstantFromCorrelatedPHI(
+    Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
+    ConstantPreference Preference, LazyValueInfo *LVI) {
   auto *ValPN = dyn_cast<PHINode>(V);
   if (!ValPN)
     return nullptr;
@@ -703,8 +701,7 @@ bool JumpThreadingPass::computeValueKnownInPredecessorsImpl(
       // predecessor, use that information to try to thread this block.
       Constant *PredCst = LVI->getConstantOnEdge(V, P, BB, CxtI);
       if (!PredCst)
-        PredCst = getKnownConstantFromCorrelatedPHI(
-            V, P, BB, Preference, LVI);
+        PredCst = getKnownConstantFromCorrelatedPHI(V, P, BB, Preference, LVI);
       // If I is a non-local compare-with-constant instruction, use more-rich
       // 'getPredicateOnEdge' method. This would be able to handle value
       // inequalities better, for example if the compare is "X < 4" and "X < 3"

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https://github.com/llvm/llvm-project/pull/190184