// If the call returns a temporary with struct return, create a temporary
// alloca to hold the result, unless one is given to us.
llvm::Value *SRetPtr = nullptr;
+ size_t UnusedReturnSize = 0;
if (RetAI.isIndirect() || RetAI.isInAlloca()) {
SRetPtr = ReturnValue.getValue();
- if (!SRetPtr)
+ if (!SRetPtr) {
SRetPtr = CreateMemTemp(RetTy);
+ if (HaveInsertPoint()) {
+ uint64_t size =
+ CGM.getDataLayout().getTypeAllocSize(ConvertTypeForMem(RetTy));
+ if (EmitLifetimeStart(size, SRetPtr))
+ UnusedReturnSize = size;
+ }
+ }
if (IRFunctionArgs.hasSRetArg()) {
IRCallArgs[IRFunctionArgs.getSRetArgNo()] = SRetPtr;
} else {
// insertion point; this allows the rest of IRgen to discard
// unreachable code.
if (CS.doesNotReturn()) {
+ if (UnusedReturnSize)
+ EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize),
+ SRetPtr);
+
Builder.CreateUnreachable();
Builder.ClearInsertionPoint();
RValue Ret = [&] {
switch (RetAI.getKind()) {
case ABIArgInfo::InAlloca:
- case ABIArgInfo::Indirect:
- return convertTempToRValue(SRetPtr, RetTy, SourceLocation());
+ case ABIArgInfo::Indirect: {
+ RValue ret = convertTempToRValue(SRetPtr, RetTy, SourceLocation());
+ if (UnusedReturnSize)
+ EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize),
+ SRetPtr);
+ return ret;
+ }
case ABIArgInfo::Ignore:
// If we are ignoring an argument that had a result, make sure to
--- /dev/null
+// RUN: %clang -target armv7l-unknown-linux-gnueabihf -S %s -o - -emit-llvm -O1 -disable-llvm-optzns | FileCheck %s
+
+// Stack should be reused when possible, no need to allocate two separate slots
+// if they have disjoint lifetime.
+
+// Sizes of objects are related to previously existed threshold of 32. In case
+// of S_large stack size is rounded to 40 bytes.
+
+// 32B
+struct S_small {
+ int a[8];
+};
+
+// 36B
+struct S_large {
+ int a[9];
+};
+
+extern S_small foo_small();
+extern S_large foo_large();
+extern void bar_small(S_small*);
+extern void bar_large(S_large*);
+
+// Prevent mangling of function names.
+extern "C" {
+
+void small_rvoed_unnamed_temporary_object() {
+// CHECK-LABEL: define void @small_rvoed_unnamed_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+
+ foo_small();
+ foo_small();
+}
+
+void large_rvoed_unnamed_temporary_object() {
+// CHECK-LABEL: define void @large_rvoed_unnamed_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+
+ foo_large();
+ foo_large();
+}
+
+void small_rvoed_named_temporary_object() {
+// CHECK-LABEL: define void @small_rvoed_named_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_smallv
+// CHECK: call void @llvm.lifetime.end
+
+ {
+ S_small s = foo_small();
+ }
+ {
+ S_small s = foo_small();
+ }
+}
+
+void large_rvoed_named_temporary_object() {
+// CHECK-LABEL: define void @large_rvoed_named_temporary_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9foo_largev
+// CHECK: call void @llvm.lifetime.end
+
+ {
+ S_large s = foo_large();
+ }
+ {
+ S_large s = foo_large();
+ }
+}
+
+void small_auto_object() {
+// CHECK-LABEL: define void @small_auto_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_smallP7S_small
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_smallP7S_small
+// CHECK: call void @llvm.lifetime.end
+
+ {
+ S_small s;
+ bar_small(&s);
+ }
+ {
+ S_small s;
+ bar_small(&s);
+ }
+}
+
+void large_auto_object() {
+// CHECK-LABEL: define void @large_auto_object
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_largeP7S_large
+// CHECK: call void @llvm.lifetime.end
+// CHECK: call void @llvm.lifetime.start
+// CHECK: call void @_Z9bar_largeP7S_large
+// CHECK: call void @llvm.lifetime.end
+
+ {
+ S_large s;
+ bar_large(&s);
+ }
+ {
+ S_large s;
+ bar_large(&s);
+ }
+}
+
+}