Attempt to fix up condition variables with temp dtors.

[klimek]

Summary

I discovered this problem when playing around with slightly
different block split-ups when inserting temp dtors; a test
would fail with "garbage value accessed" warning. After following
some red herrings while debugging, I realized that the initializer
(MyClass c = ...) was after the temp destructor call (see the test
I had to fix). I just replaced the special-case logic in VisitIfStmt
with a call to addStmt, which invokes VisitDeclStmt, which already
handles all the temporary destructor logic correctly.
If you can come up with tests that this breaks, please let me know ;)

[klimek]

Simplify the condition.

[jordan_rose]

Good catch, LGTM.

lib/Analysis/CFG.cpp

CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) {
   addSuccessor(Block, ThenBlock, /* isReachable = */ !KnownVal.isFalse());
   addSuccessor(Block, ElseBlock, /* isReachable = */ !KnownVal.isTrue());
 
   // Add the condition as the last statement in the new block.  This may create
   // new blocks as the condition may contain control-flow.  Any newly created
   // blocks will be pointed to be "Block".
   CFGBlock *LastBlock = addStmt(I->getCond());
 
-  // Finally, if the IfStmt contains a condition variable, add both the IfStmt
-  // and the condition variable initialization to the CFG.
+  // Finally, if the IfStmt contains a condition variable, add it and its
+  // initializer to the CFG.
   if (VarDecl *VD = I->getConditionVariable()) {
-    if (Expr *Init = VD->getInit()) {
-      autoCreateBlock();
-      appendStmt(Block, I->getConditionVariableDeclStmt());
-      LastBlock = addStmt(Init);
-    }
+    LastBlock =
+        addStmt(const_cast<DeclStmt *>(I->getConditionVariableDeclStmt()));
   }
 
   return LastBlock;
 }
 
 
 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) {
   // If we were in the middle of a block we stop processing that block.

test/Analysis/temp-obj-dtors-cfg-output.cpp

 // CHECK:     Preds (1): B4
 // CHECK:     Succs (2): B2 B1
 // CHECK:   [B0 (EXIT)]
 // CHECK:     Preds (2): B1 B2
 // CHECK:  int test_cond_named_custom_destructor()
 // CHECK:   [B5 (ENTRY)]
 // CHECK:     Succs (1): B4
 // CHECK:   [B1]
-// CHECK:     1: [B4.7].~C() (Implicit destructor)
+// CHECK:     1: [B4.6].~C() (Implicit destructor)
 // CHECK:     Succs (1): B0
 // CHECK:   [B2]
 // CHECK:     1: 0
 // CHECK:     2: return [B2.1];
-// CHECK:     3: [B4.7].~C() (Implicit destructor)
+// CHECK:     3: [B4.6].~C() (Implicit destructor)
 // CHECK:     Preds (1): B4
 // CHECK:     Succs (1): B0
 // CHECK:   [B3]
 // CHECK:     1: 1
 // CHECK:     2: return [B3.1];
-// CHECK:     3: [B4.7].~C() (Implicit destructor)
+// CHECK:     3: [B4.6].~C() (Implicit destructor)
 // CHECK:     Preds (1): B4
 // CHECK:     Succs (1): B0
 // CHECK:   [B4]
 // CHECK:     1: C() (CXXConstructExpr, struct C)
 // CHECK:     2: [B4.1] (BindTemporary)
 // CHECK:     3: [B4.2] (ImplicitCastExpr, NoOp, const struct C)
 // CHECK:     4: [B4.3]
 // CHECK:     5: [B4.4] (CXXConstructExpr, struct C)
-// CHECK:     6: ~C() (Temporary object destructor)
-// CHECK:     7: C c = C();
+// CHECK:     6: C c = C();
+// CHECK:     7: ~C() (Temporary object destructor)
 // CHECK:     8: c
 // CHECK:     9: [B4.8].operator bool
 // CHECK:    10: [B4.8]
 // CHECK:    11: [B4.10] (ImplicitCastExpr, UserDefinedConversion, _Bool)
 // CHECK:     T: if [B4.11]
 // CHECK:     Preds (1): B5
 // CHECK:     Succs (2): B3 B2
 // CHECK:   [B0 (EXIT)]