commit 9a4084dc06dc1b0033c461013bee3bae74be0555
author Zhongxing Xu <xuzhongxing@gmail.com> Sat Nov 13 07:30:59 2010 +0000
committer Zhongxing Xu <xuzhongxing@gmail.com> Sat Nov 13 07:30:59 2010 +0000
tree a9eb8e3bd0a464e7d7f110e3e0995b5e87194085
parent 8b8d8c90f2d8ac651d14b57f116d20b3c911ac7f

Do not add implicit dtors for CXXBindTemporaryExpr with elidable 
CXXConstructExpr.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@118991 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/CFG.cpp

diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index ef67d3b..42e0816 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -2579,11 +2579,18 @@
   return RHSBlock ? RHSBlock : LHSBlock;
 }
 
+static bool hasElidableCXXConstructExpr(CXXBindTemporaryExpr *E) {
+  if (CXXConstructExpr *CE = dyn_cast<CXXConstructExpr>(E->getSubExpr()))
+    if (CE->isElidable())
+      return true;
+  return false;
+}
+
 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors(
     CXXBindTemporaryExpr *E, bool BindToTemporary) {
   // First add destructors for temporaries in subexpression.
   CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr());
-  if (!BindToTemporary) {
+  if (!BindToTemporary && !hasElidableCXXConstructExpr(E)) {
     // If lifetime of temporary is not prolonged (by assigning to constant
     // reference) add destructor for it.
     autoCreateBlock();

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

diff --git a/test/Analysis/temp-obj-dtors-cfg-output.cpp b/test/Analysis/temp-obj-dtors-cfg-output.cpp
index 594c91b..adf509b 100644
--- a/test/Analysis/temp-obj-dtors-cfg-output.cpp
+++ b/test/Analysis/temp-obj-dtors-cfg-output.cpp
@@ -264,14 +264,11 @@
 // CHECK:    Successors (2): B3 B2
 // CHECK: [ B5 ]
 // CHECK:      1: ~A() (Temporary object destructor)
-// CHECK:      2: ~A() (Temporary object destructor)
 // CHECK:    Predecessors (1): B7
 // CHECK:    Successors (1): B4
 // CHECK: [ B6 ]
 // CHECK:      1: ~A() (Temporary object destructor)
-// CHECK:      2: ~A() (Temporary object destructor)
-// CHECK:      3: ~A() (Temporary object destructor)
-// CHECK:      4: ~B() (Temporary object destructor)
+// CHECK:      2: ~B() (Temporary object destructor)
 // CHECK:    Predecessors (1): B7
 // CHECK:    Successors (1): B4
 // CHECK: [ B7 ]
@@ -311,14 +308,11 @@
 // CHECK:    Successors (1): B0
 // CHECK: [ B2 ]
 // CHECK:      1: ~A() (Temporary object destructor)
-// CHECK:      2: ~A() (Temporary object destructor)
 // CHECK:    Predecessors (1): B4
 // CHECK:    Successors (1): B1
 // CHECK: [ B3 ]
 // CHECK:      1: ~A() (Temporary object destructor)
-// CHECK:      2: ~A() (Temporary object destructor)
-// CHECK:      3: ~A() (Temporary object destructor)
-// CHECK:      4: ~B() (Temporary object destructor)
+// CHECK:      2: ~B() (Temporary object destructor)
 // CHECK:    Predecessors (1): B4
 // CHECK:    Successors (1): B1
 // CHECK: [ B4 ]
@@ -351,8 +345,7 @@
 // CHECK:    Successors (1): B7
 // CHECK: [ B9 ]
 // CHECK:      1: ~A() (Temporary object destructor)
-// CHECK:      2: ~A() (Temporary object destructor)
-// CHECK:      3: ~B() (Temporary object destructor)
+// CHECK:      2: ~B() (Temporary object destructor)
 // CHECK:    Predecessors (1): B10
 // CHECK:    Successors (1): B7
 // CHECK: [ B10 ]
@@ -392,7 +385,6 @@
 // CHECK:    Successors (1): B0
 // CHECK: [ B2 ]
 // CHECK:      1: ~A() (Temporary object destructor)
-// CHECK:      2: ~A() (Temporary object destructor)
 // CHECK:    Predecessors (1): B3
 // CHECK:    Successors (1): B1
 // CHECK: [ B3 ]
@@ -426,7 +418,6 @@
 // CHECK:    Successors (1): B0
 // CHECK: [ B2 ]
 // CHECK:      1: ~A() (Temporary object destructor)
-// CHECK:      2: ~A() (Temporary object destructor)
 // CHECK:    Predecessors (1): B3
 // CHECK:    Successors (1): B1
 // CHECK: [ B3 ]