llvm-project/llvm/test/CodeGen/PowerPC/tailcall-string-rvo.ll

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; RUN: llc -O2 < %s | FileCheck %s
; The call to function TestBar should be a tail call, when in C++ the string
; `ret` is RVO returned.
; string TestFoo() {
; string ret = undef;
; TestBar(&ret); // tail call optimized
; return ret;
; }
target triple = "powerpc64le-linux-gnu"
%class.basic_string.11.42.73 = type { %"class.__gnu_cxx::__versa_string.10.41.72" }
%"class.__gnu_cxx::__versa_string.10.41.72" = type { %"class.__gnu_cxx::__sso_string_base.9.40.71" }
%"class.__gnu_cxx::__sso_string_base.9.40.71" = type { %"struct.__gnu_cxx::__vstring_utility<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider.7.38.69", i64, %union.anon.8.39.70 }
%"struct.__gnu_cxx::__vstring_utility<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider.7.38.69" = type { i8* }
%union.anon.8.39.70 = type { i64, [8 x i8] }
declare void @TestBaz(%class.basic_string.11.42.73* noalias sret %arg)
define void @TestBar(%class.basic_string.11.42.73* noalias sret %arg) {
bb:
call void @TestBaz(%class.basic_string.11.42.73* noalias sret %arg)
ret void
}
define void @TestFoo(%class.basic_string.11.42.73* noalias sret %arg) {
; CHECK-LABEL: TestFoo:
; CHECK: #TC_RETURNd8 TestBar 0
bb:
%tmp = getelementptr inbounds %class.basic_string.11.42.73, %class.basic_string.11.42.73* %arg, i64 0, i32 0, i32 0, i32 2
%tmp1 = bitcast %class.basic_string.11.42.73* %arg to %union.anon.8.39.70**
store %union.anon.8.39.70* %tmp, %union.anon.8.39.70** %tmp1, align 8
%tmp2 = bitcast %union.anon.8.39.70* %tmp to i8*
tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %tmp2, i8* nonnull undef, i64 13, i32 1, i1 false)
%tmp3 = getelementptr inbounds %class.basic_string.11.42.73, %class.basic_string.11.42.73* %arg, i64 0, i32 0, i32 0, i32 1
store i64 13, i64* %tmp3, align 8
%tmp4 = getelementptr inbounds %class.basic_string.11.42.73, %class.basic_string.11.42.73* %arg, i64 0, i32 0, i32 0, i32 2, i32 1, i64 5
store i8 0, i8* %tmp4, align 1
tail call void @TestBar(%class.basic_string.11.42.73* noalias sret %arg)
ret void
}
; Function Attrs: argmemonly nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #0
attributes #0 = { argmemonly nounwind }