https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63803
Bug ID: 63803
Summary: When GCC 4.9.2 compile with option -O2, the target is
error.
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: airbak.li at huawei dot com
The option -fisolate-erroneous-paths-dereference in -O2 causes it.
1.file b.c:
int main()
{
//volatile unsigned int
//unsigned int orgin = *((int *)0); //ok
//unsigned int orgin = *((unsigned int *)0); //ok
unsigned int orgin = *((volatile unsigned int *)0); //nok
printf("---");
return 0;
}
2.compile:
arm-none-eabi-gcc --specs=nosys.specs -O2 b.c -o b
or
arm-none-eabi-gcc --specs=nosys.specs -O1 -fisolate-erroneous-paths-dereference
b.c -o b
3.asm
00008210 <main>:
8210: e3a03000 mov r3, #0
8214: e5933000 ldr r3, [r3]
8218: e7f000f0 udf #0
4.question:
Why it is "udf #0"?
Is it a BUG?
Please help me, thanks!
