Fix a bug in the dead stores checker reported in the following email:
http://lists.cs.uiuc.edu/pipermail/cfe-dev/2008-July/002157.html
Essentially the observer mechanism in LiveVariables was observing block-level
expressions multiple times, leading to a case where the dead store checker could
see a value as dead when it was really live.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@53115 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/LiveVariables.cpp b/lib/Analysis/LiveVariables.cpp
index 54e2195..8f391dc 100644
--- a/lib/Analysis/LiveVariables.cpp
+++ b/lib/Analysis/LiveVariables.cpp
@@ -133,15 +133,23 @@
};
void TransferFuncs::Visit(Stmt *S) {
- if (AD.Observer)
- AD.Observer->ObserveStmt(S,AD,LiveState);
if (S == getCurrentBlkStmt()) {
+
+ if (AD.Observer)
+ AD.Observer->ObserveStmt(S,AD,LiveState);
+
if (getCFG().isBlkExpr(S)) LiveState(S,AD) = Dead;
StmtVisitor<TransferFuncs,void>::Visit(S);
}
- else if (!getCFG().isBlkExpr(S))
+ else if (!getCFG().isBlkExpr(S)) {
+
+ if (AD.Observer)
+ AD.Observer->ObserveStmt(S,AD,LiveState);
+
StmtVisitor<TransferFuncs,void>::Visit(S);
+
+ }
else
// For block-level expressions, mark that they are live.
LiveState(S,AD) = Alive;