llvm-project/clang/test/CodeGen/attr-disable-tail-calls.c
Akira Hatanaka 7828b1e604 Add support for function attribute 'disable_tail_calls'.
The ``disable_tail_calls`` attribute instructs the backend to not
perform tail call optimization inside the marked function.

For example, 

int callee(int);

int foo(int a) __attribute__((disable_tail_calls)) {
  return callee(a); // This call is not tail-call optimized.
}

Note that this attribute is different from 'not_tail_called', which
prevents tail-call optimization to the marked function.

rdar://problem/8973573

Differential Revision: http://reviews.llvm.org/D12547

llvm-svn: 252986
2015-11-13 00:42:21 +00:00

20 lines
773 B
C

// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 %s -emit-llvm -mdisable-tail-calls -o - | FileCheck %s -check-prefix=DISABLE
// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 %s -emit-llvm -o - | FileCheck %s -check-prefix=ENABLE
// DISABLE: define i32 @f1() [[ATTRTRUE:#[0-9]+]] {
// DISABLE: define i32 @f2() [[ATTRTRUE]] {
// ENABLE: define i32 @f1() [[ATTRFALSE:#[0-9]+]] {
// ENABLE: define i32 @f2() [[ATTRTRUE:#[0-9]+]] {
int f1() {
return 0;
}
int f2() __attribute__((disable_tail_calls)) {
return 0;
}
// DISABLE: attributes [[ATTRTRUE]] = { {{.*}}"disable-tail-calls"="true"{{.*}} }
// ENABLE: attributes [[ATTRFALSE]] = { {{.*}}"disable-tail-calls"="false"{{.*}} }
// ENABLE: attributes [[ATTRTRUE]] = { {{.*}}"disable-tail-calls"="true"{{.*}} }