[llvm-branch-commits] [clang] [LifetimeSafety][NFC] Update Checker to use prefix comparison interfaces (PR #207519)

[Utkarsh Saxena via llvm-branch-commits]

https://github.com/usx95 updated https://github.com/llvm/llvm-project/pull/207519

>From 16f77ac1a8dedc19b87aaa7361239135ae25696d Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Sat, 4 Jul 2026 16:17:19 +0000
Subject: [PATCH] [LifetimeSafety][NFC] Update Checker to use prefix comparison
 interfaces

This patch switches the Checker's expiry and invalidation checks to use `AccessPath::isPrefixOf` instead of equality (`==`).

Since all generated access paths are currently empty, `isPrefixOf` is behaviorally identical to `==` (NFC). This prepares the checker to handle nested paths (fields and container interiors) in subsequent commits.

TAG=agy
CONV=2cfd8d00-18d7-4a03-8d78-2aba2f9a8f23
---
 clang/lib/Analysis/LifetimeSafety/Checker.cpp | 34 +++++++++----------
 .../Analysis/LifetimeSafety/MovedLoans.cpp    |  2 +-
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/clang/lib/Analysis/LifetimeSafety/Checker.cpp b/clang/lib/Analysis/LifetimeSafety/Checker.cpp
index 4deead08e6fed..7bb02394138aa 100644
--- a/clang/lib/Analysis/LifetimeSafety/Checker.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/Checker.cpp
@@ -188,22 +188,22 @@ class LifetimeChecker {
       LoanSet HeldLoans = LoanPropagation.getLoans(OID, EF);
       for (LoanID HeldLoanID : HeldLoans) {
         const Loan *HeldLoan = FactMgr.getLoanMgr().getLoan(HeldLoanID);
-        if (ExpiredPath != HeldLoan->getAccessPath())
-          continue;
-        // HeldLoan is expired because its AccessPath is expired.
-        PendingWarning &CurWarning = FinalWarningsMap[HeldLoan->getID()];
-        const Expr *MovedExpr = nullptr;
-        if (auto *ME = MovedLoans.getMovedLoans(EF).lookup(HeldLoanID))
-          MovedExpr = *ME;
-        // Skip if we already have a dominating causing fact.
-        if (CurWarning.CausingFactDominatesExpiry)
-          continue;
-        if (causingFactDominatesExpiry(LiveInfo.Kind))
-          CurWarning.CausingFactDominatesExpiry = true;
-        CurWarning.CausingFact = LiveInfo.CausingFact;
-        CurWarning.ExpiryLoc = EF->getExpiryLoc();
-        CurWarning.MovedExpr = MovedExpr;
-        CurWarning.InvalidatedByExpr = nullptr;
+        if (ExpiredPath.isPrefixOf(HeldLoan->getAccessPath())) {
+          // HeldLoan is expired because its base or itself is expired.
+          PendingWarning &CurWarning = FinalWarningsMap[HeldLoan->getID()];
+          const Expr *MovedExpr = nullptr;
+          if (auto *ME = MovedLoans.getMovedLoans(EF).lookup(HeldLoanID))
+            MovedExpr = *ME;
+          // Skip if we already have a dominating causing fact.
+          if (CurWarning.CausingFactDominatesExpiry)
+            continue;
+          if (causingFactDominatesExpiry(LiveInfo.Kind))
+            CurWarning.CausingFactDominatesExpiry = true;
+          CurWarning.CausingFact = LiveInfo.CausingFact;
+          CurWarning.ExpiryLoc = EF->getExpiryLoc();
+          CurWarning.MovedExpr = MovedExpr;
+          CurWarning.InvalidatedByExpr = nullptr;
+        }
       }
     }
   }
@@ -223,7 +223,7 @@ class LifetimeChecker {
     auto IsInvalidated = [&](const Loan *L) {
       for (LoanID InvalidID : DirectlyInvalidatedLoans) {
         const Loan *InvalidL = FactMgr.getLoanMgr().getLoan(InvalidID);
-        if (InvalidL->getAccessPath() == L->getAccessPath())
+        if (InvalidL->getAccessPath().isPrefixOf(L->getAccessPath()))
           return true;
       }
       return false;
diff --git a/clang/lib/Analysis/LifetimeSafety/MovedLoans.cpp b/clang/lib/Analysis/LifetimeSafety/MovedLoans.cpp
index 138704821024a..1a9ce3e576733 100644
--- a/clang/lib/Analysis/LifetimeSafety/MovedLoans.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/MovedLoans.cpp
@@ -80,7 +80,7 @@ class AnalysisImpl
     auto IsInvalidated = [&](const AccessPath &Path) {
       for (LoanID LID : ImmediatelyMovedLoans) {
         const Loan *MovedLoan = LoanMgr.getLoan(LID);
-        if (MovedLoan->getAccessPath() == Path)
+        if (MovedLoan->getAccessPath().isPrefixOf(Path))
           return true;
       }
       return false;