[cfe-commits] r130453 - in /cfe/trunk: lib/CodeGen/CGExprAgg.cpp lib/CodeGen/CGExprCXX.cpp test/CodeGenCXX/value-init.cpp
Argyrios Kyrtzidis
akyrtzi at gmail.com
Thu Apr 28 15:57:55 PDT 2011
Author: akirtzidis
Date: Thu Apr 28 17:57:55 2011
New Revision: 130453
URL: http://llvm.org/viewvc/llvm-project?rev=130453&view=rev
Log:
Cut down unnecessary zero'ing when value-initializing arrays of C++ objects.
-C++ objects with user-declared constructor don't need zero'ing.
-We can zero-initialize arrays of C++ objects in "bulk" now, in which case don't zero-initialize each object again.
Modified:
cfe/trunk/lib/CodeGen/CGExprAgg.cpp
cfe/trunk/lib/CodeGen/CGExprCXX.cpp
cfe/trunk/test/CodeGenCXX/value-init.cpp
Modified: cfe/trunk/lib/CodeGen/CGExprAgg.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprAgg.cpp?rev=130453&r1=130452&r2=130453&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprAgg.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprAgg.cpp Thu Apr 28 17:57:55 2011
@@ -811,7 +811,16 @@
// If the slot is already known to be zeroed, nothing to do. Don't mess with
// volatile stores.
if (Slot.isZeroed() || Slot.isVolatile() || Slot.getAddr() == 0) return;
-
+
+ // C++ objects with a user-declared constructor don't need zero'ing.
+ if (CGF.getContext().getLangOptions().CPlusPlus)
+ if (const RecordType *RT = CGF.getContext()
+ .getBaseElementType(E->getType())->getAs<RecordType>()) {
+ const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
+ if (RD->hasUserDeclaredConstructor())
+ return;
+ }
+
// If the type is 16-bytes or smaller, prefer individual stores over memset.
std::pair<CharUnits, CharUnits> TypeInfo =
CGF.getContext().getTypeInfoInChars(E->getType());
Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=130453&r1=130452&r2=130453&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Thu Apr 28 17:57:55 2011
@@ -370,8 +370,9 @@
// If we require zero initialization before (or instead of) calling the
// constructor, as can be the case with a non-user-provided default
- // constructor, emit the zero initialization now.
- if (E->requiresZeroInitialization())
+ // constructor, emit the zero initialization now, unless destination is
+ // already zeroed.
+ if (E->requiresZeroInitialization() && !Dest.isZeroed())
EmitNullInitialization(Dest.getAddr(), E->getType());
// If this is a call to a trivial default constructor, do nothing.
Modified: cfe/trunk/test/CodeGenCXX/value-init.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/value-init.cpp?rev=130453&r1=130452&r2=130453&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/value-init.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/value-init.cpp Thu Apr 28 17:57:55 2011
@@ -101,23 +101,37 @@
// CHECK: define void @_ZN6PR98011fEv
void f() {
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98014TestC1Ei
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98014TestC1Ev
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98014TestC1Ev
Test partial[3] = { 1 };
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98014TestC1Ev
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98014TestC1Ev
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98014TestC1Ev
Test empty[3] = {};
+ // CHECK: call void @llvm.memset.p0i8.i64
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98015Test2C1Ev
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98015Test2C1Ev
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98015Test2C1Ev
Test2 empty2[3] = {};
+ // CHECK: call void @llvm.memset.p0i8.i64
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98015Test3C1Ev
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98015Test3C1Ev
+ // CHECK-NOT: call void @llvm.memset.p0i8.i64
// CHECK: call void @_ZN6PR98015Test3C1Ev
Test3 empty3[3] = {};
}
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