http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59734
Bug ID: 59734
Summary: Simple strict-volatile-bitfields case not working
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: joey.ye at arm dot com
$ cat v.c
struct str {
volatile unsigned f1: 8;
};
int foo(struct str *a)
{
a->f1=sizeof(struct str);
}
$ arm-none-eabi-gcc -mthumb -mcpu=cortex-m3 -Os -fstrict-volatile-bitfields v.c
-S
4.6:
ldr r3, [r0, #0] <= Correct. Load word
movs r2, #4
bfi r3, r2, #0, #8
str r3, [r0, #0]
bx lr
4.7:
ldrb r3, [r0, #0] @ zero_extendqisi2 <= Incorrect. Load byte
movs r3, #4
strb r3, [r0, #0]
bx lr
4.8 and latest trunk (date 20140108, after Sandra and Bernd's fixes):
ldrb r3, [r0] @ zero_extendqisi2 <= Incorrect. Load byte
movs r2, #4
bfi r3, r2, #0, #8
strb r3, [r0]
bx lr
