r207888 - [leaks] Fix a leak of a basic block when we successfully fold a switch

[Chandler Carruth]

Author: chandlerc
Date: Fri May  2 19:14:49 2014
New Revision: 207888

URL: http://llvm.org/viewvc/llvm-project?rev=207888&view=rev
Log:
[leaks] Fix a leak of a basic block when we successfully fold a switch
condition to a constant and emit only the relevant statement. In that
case, we were previously creating the epilog jump destination, a cleanup
scope, and emitting any condition variable into it. Instead, we can emit
the condition variable (if we have one) into the cleanup scope used for
the entire folded case sequence. We avoid creating a jump dest, a basic
block, and an extra cleanup scope. Win!

Modified:
    cfe/trunk/lib/CodeGen/CGStmt.cpp

Modified: cfe/trunk/lib/CodeGen/CGStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGStmt.cpp?rev=207888&r1=207887&r2=207888&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGStmt.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGStmt.cpp Fri May  2 19:14:49 2014
@@ -1302,13 +1302,6 @@ static bool FindCaseStatementsForValue(c
 }
 
 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
-  JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
-
-  RunCleanupsScope ConditionScope(*this);
-
-  if (S.getConditionVariable())
-    EmitAutoVarDecl(*S.getConditionVariable());
-
   // Handle nested switch statements.
   llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
   SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
@@ -1328,6 +1321,11 @@ void CodeGenFunction::EmitSwitchStmt(con
       }
       RunCleanupsScope ExecutedScope(*this);
 
+      // Emit the condition variable if needed inside the entire cleanup scope
+      // used by this special case for constant folded switches.
+      if (S.getConditionVariable())
+        EmitAutoVarDecl(*S.getConditionVariable());
+
       // At this point, we are no longer "within" a switch instance, so
       // we can temporarily enforce this to ensure that any embedded case
       // statements are not emitted.
@@ -1348,6 +1346,11 @@ void CodeGenFunction::EmitSwitchStmt(con
     }
   }
 
+  JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
+
+  RunCleanupsScope ConditionScope(*this);
+  if (S.getConditionVariable())
+    EmitAutoVarDecl(*S.getConditionVariable());
   llvm::Value *CondV = EmitScalarExpr(S.getCond());
 
   // Create basic block to hold stuff that comes after switch