From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 16 Feb 2012 22:45:48 +0000 (+0000)
Subject: Elide copy construction in new expressions.  PR11757.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=22cfaf512e4f66105fb1f8dd39e0a77787fbdf9b;p=clang

Elide copy construction in new expressions.  PR11757.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150738 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index 12bdc7e43f..47e57032e0 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -890,20 +890,6 @@ static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
     return;
   }
 
-  if (const CXXConstructExpr *CCE = dyn_cast_or_null<CXXConstructExpr>(Init)) {
-    CXXConstructorDecl *Ctor = CCE->getConstructor();
-    // Per C++ [expr.new]p15, if we have an initializer, then we're performing
-    // direct initialization. C++ [dcl.init]p5 requires that we 
-    // zero-initialize storage if there are no user-declared constructors.
-    if (!Ctor->getParent()->hasUserDeclaredConstructor() &&
-        !Ctor->getParent()->isEmpty())
-      CGF.EmitNullInitialization(NewPtr, ElementType);
-
-    CGF.EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false,
-                               NewPtr, CCE->arg_begin(), CCE->arg_end());
-    return;
-  }
-  // We have a POD type.
   if (!Init)
     return;
 
diff --git a/test/CodeGenCXX/debug-info-limit.cpp b/test/CodeGenCXX/debug-info-limit.cpp
index 75f9271b00..bca887b4db 100644
--- a/test/CodeGenCXX/debug-info-limit.cpp
+++ b/test/CodeGenCXX/debug-info-limit.cpp
@@ -7,8 +7,8 @@ public:
   int z;
 };
 
-A *foo () {
-  A *a = new A();
+A *foo (A* x) {
+  A *a = new A(*x);
   return a;
 }
 
diff --git a/test/CodeGenCXX/exceptions.cpp b/test/CodeGenCXX/exceptions.cpp
index 2a5cbb4900..079c1e5e72 100644
--- a/test/CodeGenCXX/exceptions.cpp
+++ b/test/CodeGenCXX/exceptions.cpp
@@ -194,12 +194,9 @@ namespace test3 {
     // CHECK:      [[SAVED0:%.*]] = alloca i8*
     // CHECK-NEXT: [[SAVED1:%.*]] = alloca i8*
     // CHECK-NEXT: [[CLEANUPACTIVE:%.*]] = alloca i1
-    // CHECK-NEXT: [[TMP:%.*]] = alloca [[A]], align 8
-    // CHECK:      [[TMPACTIVE:%.*]] = alloca i1
 
     // CHECK:      [[COND:%.*]] = trunc i8 {{.*}} to i1
     // CHECK-NEXT: store i1 false, i1* [[CLEANUPACTIVE]]
-    // CHECK-NEXT: store i1 false, i1* [[TMPACTIVE]]
     // CHECK-NEXT: br i1 [[COND]]
     return (cond ?
 
@@ -209,24 +206,18 @@ namespace test3 {
     // CHECK-NEXT: store i8* [[FOO]], i8** [[SAVED1]]
     // CHECK-NEXT: store i1 true, i1* [[CLEANUPACTIVE]]
     // CHECK-NEXT: [[CAST:%.*]] = bitcast i8* [[NEW]] to [[A]]*
-    // CHECK-NEXT: invoke void @_ZN5test35makeAEv([[A]]* sret [[TMP]])
-    // CHECK:      store i1 true, i1* [[TMPACTIVE]]
-    // CHECK-NEXT: invoke void @_ZN5test31AC1ERKS0_([[A]]* [[CAST]], [[A]]* [[TMP]])
-    // CHECK:      store i1 false, i1* [[CLEANUPACTIVE]]
-    // CHECK-NEXT: br label
+    // CHECK-NEXT: invoke void @_ZN5test35makeAEv([[A]]* sret [[CAST]])
+    // CHECK: br label
     //   -> cond.end
             new(foo(),10.0) A(makeA()) :
 
-    // CHECK:      [[MAKE:%.*]] = invoke [[A]]* @_ZN5test38makeAPtrEv()
+    // CHECK:      [[MAKE:%.*]] = call [[A]]* @_ZN5test38makeAPtrEv()
     // CHECK:      br label
     //   -> cond.end
             makeAPtr());
 
     // cond.end:
     // CHECK:      [[RESULT:%.*]] = phi [[A]]* {{.*}}[[CAST]]{{.*}}[[MAKE]]
-    // CHECK-NEXT: [[ISACTIVE:%.*]] = load i1* [[TMPACTIVE]]
-    // CHECK-NEXT: br i1 [[ISACTIVE]]
-    // CHECK:      invoke void @_ZN5test31AD1Ev
     // CHECK:      ret [[A]]* [[RESULT]]
 
     // in the EH path:
diff --git a/test/CodeGenCXX/new.cpp b/test/CodeGenCXX/new.cpp
index 810a585bca..8d9f641ba1 100644
--- a/test/CodeGenCXX/new.cpp
+++ b/test/CodeGenCXX/new.cpp
@@ -239,3 +239,14 @@ namespace PR11523 {
   // CHECK: store i64 -1
   NewTy* f() { return new NewTy[2](); }
 }
+
+namespace PR11757 {
+  // Make sure we elide the copy construction.
+  struct X { X(); X(const X&); };
+  X* a(X* x) { return new X(X()); }
+  // CHECK: define {{.*}} @_ZN7PR117571aEPNS_1XE
+  // CHECK: [[CALL:%.*]] = call noalias i8* @_Znwm
+  // CHECK-NEXT: [[CASTED:%.*]] = bitcast i8* [[CALL]] to
+  // CHECK-NEXT: call void @_ZN7PR117571XC1Ev({{.*}}* [[CASTED]])
+  // CHECK-NEXT: ret {{.*}} [[CASTED]]
+}
diff --git a/test/CodeGenObjCXX/copy.mm b/test/CodeGenObjCXX/copy.mm
index a61ccd4e5d..9382ee870a 100644
--- a/test/CodeGenObjCXX/copy.mm
+++ b/test/CodeGenObjCXX/copy.mm
@@ -14,8 +14,6 @@ namespace test0 {
   // CHECK-NEXT: call noalias i8* @_Znwm(
   // CHECK-NEXT: bitcast
   // CHECK-NEXT: bitcast
-  // CHECK-NEXT: call void @llvm.memset.p0i8.i64(
-  // CHECK-NEXT: bitcast
   // CHECK-NEXT: bitcast
   // CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(
   // CHECK-NEXT: ret