The attached code produces wrong-code on gcc-4.1.1 and gcc-4.1.2 on ARM. These
codes are snippet from linux kernel, and this was found when linux v2.6.19 was
built with gcc-4.1.1 with CONFIG_PRINK_TIME=y is set for ARM.
$ arm-linux-gcc -O2 -c div64.S
$ arm-linux-gcc -O2 -save-temps dodiv.c div64.o -o dodiv
actual result:
$ ./dodiv
tbuf: <4>[ 52.305419]
expected result:
tbuf: <4>[ 0.305419]
when compiled with -fno-tree-ter, the result was OK.
The problem comes from bad argument passing to sprintf(), looking from
dodiv.s:
...
mov r2, r5 <<<<<< (1)
mov ip, ip, lsr #6
mov r3, r5 <<<<<< (2)
ldr r1, .L10+8
mov r0, r4
str ip, [sp, #0]
bl sprintf
Where (1) is loglev_char argument and (2) is (unsigned long)t argument in
sprintf() in dodiv.c. Apparently, the loglev_char is also assigned to the first
%5lu part of sprintf, which is the cause.
--
Summary: bad argument passing on ARM
Product: gcc
Version: 4.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: kaminaga at sm dot sony dot co dot jp
GCC target triplet: arm-*-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31143
