Remove threshold for inserting lifetime markers for named temporaries

Now that TailRecursionElimination has been fixed with r222354, the
threshold on size for lifetime marker insertion can be removed. This
only affects named temporary though, as the patch for unnamed temporaries
is still in progress.

My previous commit (r222993) was not handling debuginfo correctly, but
this could only be seen with some asan tests. Basically, lifetime markers
are just instrumentation for the compiler's usage and should not affect
debug information; however, the cleanup infrastructure was assuming it
contained only destructors, i.e. actual code to be executed, and was
setting the breakpoint for the end of the function to the closing '}', and
not the return statement, in order to show some destructors have been
called when leaving the function. This is wrong when the cleanups are only
lifetime markers, and this is now fixed.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@234581 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/test/CodeGen/cleanup-destslot-simple.c b/test/CodeGen/cleanup-destslot-simple.c
new file mode 100644
index 0000000000..0ee52e1d9f
--- /dev/null
+++ b/test/CodeGen/cleanup-destslot-simple.c
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -O1 -triple x86_64-none-linux-gnu -emit-llvm -gline-tables-only %s -o - | FileCheck %s
+
+// There is no exception to handle here, lifetime.end is not a destructor,
+// so there is no need have cleanup dest slot related code
+// CHECK-LABEL: define i32 @test
+int test() {
+  int x = 3;
+  int *volatile p = &x;
+  return *p;
+// CHECK: [[X:%.*]] = alloca i32
+// CHECK: [[P:%.*]] = alloca i32*
+// CHECK: call void @llvm.lifetime.start(i64 4, i8* %{{.*}})
+// CHECK: call void @llvm.lifetime.start(i64 8, i8* %{{.*}})
+// CHECK-NOT: store i32 %{{.*}}, i32* %cleanup.dest.slot
+}