https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122539
Bug ID: 122539
Summary: CMSE wrongfully clearing non padded union members
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: avieira at gcc dot gnu.org
Target Milestone: ---
When compiling something like:
#include <arm_cmse.h>
union u_t_0 {
long long ll;
};
typedef void(__attribute__((cmse_nonsecure_call)) fn_t_0)(union u_t_0);
void fn_caller_0(fn_t_0 *f_ptr) {
union u_t_0 x = {1234};
f_ptr(x);
}
with -march=armv8-m.mainline -mcmse -O2 -mfloat-abi=soft
the compiler will generate the following assembly:
...
movw r0, #1234
lsrs r4, r4, #1
lsls r4, r4, #1
mov r0, r4
mov r1, r4
mov r2, r4
mov r3, r4
bl __gnu_cmse_nonsecure_call
...
where the 'mov r0, r4' wrongfully clears teh argument to the nonsecure call.
