Since https://github.com/llvm/llvm-project/pull/109628 landed, this test
has been failing on 32-bit Arm.
This is due to a codegen problem (whether added or uncovered by the change,
not known) where the trap instruction is placed after the frame pointer
and link register are restored.
https://github.com/llvm/llvm-project/issues/113154
So the code was:
```
std::__1::vector<int>::operator[](unsigned int):
sub sp, sp, #8
str r0, [sp, #4]
str r1, [sp]
add sp, sp, #8
.inst 0xe7ffdefe
bx lr
```
When lldb saw the trap, the PC was inside operator[] but the frame
information actually pointed to g.
This bug only happens for leaf functions so adding a return type
works around it:
```
std::__1::vector<int>::operator[](unsigned int):
push {r11, lr}
mov r11, sp
sub sp, sp, #8
str r0, [sp, #4]
str r1, [sp]
mov sp, r11
pop {r11, lr}
.inst 0xe7ffdefe
bx lr
```
(and operator[] should return T& anyway)
Now the PC location and frame information should match and the
test passes.
c47df3e8c8