https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105981
Bug ID: 105981
Summary: Wrong code generated when compiling for arm cortex-a72
in AARCH32 with -mbig-endian
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: gjimenez at teldat dot com
Target Milestone: ---
Created attachment 53137
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53137&action=edit
files with the source and results for cortex-a72 and cortex-a53
When compiling a file("test.c") with a simple function like this:
void test(char *buf)
{
__builtin_strcpy(buf, "abcd1234");
}
With this:
../x-tools/armeb-none-eabi/bin/armeb-none-eabi-gcc -c -Wall -Wextra -O3
-mbig-endian -ffreestanding -fbuiltin -nostdinc -save-temps -mcpu=cortex-a72
test.c -o test.a72
The code generated is:
.LC0:
.ascii "abcd1234\000"
.text
.align 2
.global test
.syntax unified
.arm
.type test, %function
test:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
movw r3, #:lower16:.LC0
movt r3, #:upper16:.LC0
strd r4, [sp, #-8]!
ldrd r4, [r3]
ldrb r3, [r3, #8] @ zero_extendqisi2
str r5, [r0] @ unaligned
str r4, [r0, #4] @ unaligned
ldrd r4, [sp]
add sp, sp, #8
strb r3, [r0, #8]
bx lr
String read:
In "ldrd r4, [r3]" It reads the string "abcd1234" into r4 and r5. (I am
skipping the null string terminator. It is written ok).
Buffer fill:
Then, it writes r5 into the start of the buffer "str r5, [r0]"
And then r4 in the offset 4 of the buffer "str r4, [r0, #4]".
The result is that we get the buffer with the string 32bits-swapped "1234abcd".
*** WRONG RESULT ***
But, if we compile the same file with -mcpu=cortex-a53 it works fine:
.LC0:
.ascii "abcd1234\000"
.text
.align 2
.global test
.syntax unified
.arm
.type test, %function
test:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
movw r3, #:lower16:.LC0
movt r3, #:upper16:.LC0
mov r2, r0
ldmia r3!, {r0, r1}
str r0, [r2] @ unaligned
str r1, [r2, #4] @ unaligned
ldrb r3, [r3] @ zero_extendqisi2
strb r3, [r2, #8]
bx lr
String read:
ldmia r3!, {r0, r1}
Buffer fill:
str r0, [r2] @ unaligned
str r1, [r2, #4] @ unaligned
*** CORRECT ORDER ***
The gcc release:
git log -1
commit 1ea978e3066ac565a1ec28a96a4d61eaf38e2726 (HEAD, tag:
releases/gcc-12.1.0)
Author: Jakub Jelinek <ja...@redhat.com>
Date: Fri May 6 07:07:53 2022 +0000
Update ChangeLog and version files for release
git remote -v
origin git://gcc.gnu.org/git/gcc.git (fetch)
origin git://gcc.gnu.org/git/gcc.git (push)
The output when I add the "-v" option:
../x-tools/armeb-none-eabi/bin/armeb-none-eabi-gcc -v -c -Wall -Wextra -O3
-mbig-endian -ffreestanding -fbuiltin -nostdinc -save-temps -mcpu=cortex-a72
test.c -o test.a72
Using built-in specs.
COLLECT_GCC=../x-tools/armeb-none-eabi/bin/armeb-none-eabi-gcc
Target: armeb-none-eabi
Configured with:
/home/gjimenez/gcc/crosstool-ng/.build/armeb-none-eabi/src/gcc/configure
--build=x86_64-build_pc-linux-gnu --host=x86_64-build_pc-linux-gnu
--target=armeb-none-eabi --prefix=/home/gjimenez/x-tools/armeb-none-eabi
--exec_prefix=/home/gjimenez/x-tools/armeb-none-eabi
--with-local-prefix=/home/gjimenez/x-tools/armeb-none-eabi/armeb-none-eabi
--with-headers=/home/gjimenez/x-tools/armeb-none-eabi/armeb-none-eabi/include
--with-newlib --enable-threads=no --disable-shared
--with-pkgversion='crosstool-NG 1.25.0.36_a3e3d73' --enable-__cxa_atexit
--disable-libgomp --disable-libmudflap --disable-libmpx --disable-libssp
--disable-libquadmath --disable-libquadmath-support --disable-libstdcxx-verbose
--with-gmp=/home/gjimenez/gcc/crosstool-ng/.build/armeb-none-eabi/buildtools
--with-mpfr=/home/gjimenez/gcc/crosstool-ng/.build/armeb-none-eabi/buildtools
--with-mpc=/home/gjimenez/gcc/crosstool-ng/.build/armeb-none-eabi/buildtools
--with-isl=/home/gjimenez/gcc/crosstool-ng/.build/armeb-none-eabi/buildtools
--disable-lto --enable-target-optspace --disable-nls --enable-multiarch
--with-multilib-list='rmprofile aprofile' --enable-languages=c,c++
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 12.1.0 (crosstool-NG 1.25.0.36_a3e3d73)
COLLECT_GCC_OPTIONS='-v' '-c' '-Wall' '-Wextra' '-O3' '-mbig-endian'
'-ffreestanding' '-fbuiltin' '-nostdinc' '-save-temps' '-mcpu=cortex-a72' '-o'
'test.a72' '-mfloat-abi=soft' '-marm' '-mlibarch=armv8-a+crc'
'-march=armv8-a+crc'
/home/gjimenez/x-tools/armeb-none-eabi/libexec/gcc/armeb-none-eabi/12.1.0/cc1
-E -quiet -nostdinc -v -imultilib thumb/v8-a/nofp -D__USES_INITFINI__ test.c
-mbig-endian -mcpu=cortex-a72 -mfloat-abi=soft -marm -mlibarch=armv8-a+crc
-march=armv8-a+crc -Wall -Wextra -ffreestanding -fbuiltin -O3 -fpch-preprocess
-o test.i
#include "..." search starts here:
#include <...> search starts here:
End of search list.
COLLECT_GCC_OPTIONS='-v' '-c' '-Wall' '-Wextra' '-O3' '-mbig-endian'
'-ffreestanding' '-fbuiltin' '-nostdinc' '-save-temps' '-mcpu=cortex-a72' '-o'
'test.a72' '-mfloat-abi=soft' '-marm' '-mlibarch=armv8-a+crc'
'-march=armv8-a+crc'
/home/gjimenez/x-tools/armeb-none-eabi/libexec/gcc/armeb-none-eabi/12.1.0/cc1
-fpreprocessed test.i -quiet -dumpbase test.c -dumpbase-ext .c -mbig-endian
-mcpu=cortex-a72 -mfloat-abi=soft -marm -mlibarch=armv8-a+crc
-march=armv8-a+crc -O3 -Wall -Wextra -version -ffreestanding -fbuiltin -o
test.s
GNU C17 (crosstool-NG 1.25.0.36_a3e3d73) version 12.1.0 (armeb-none-eabi)
compiled by GNU C version 9.4.0, GMP version 6.2.1, MPFR version 4.1.0,
MPC version 1.2.1, isl version isl-0.24-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C17 (crosstool-NG 1.25.0.36_a3e3d73) version 12.1.0 (armeb-none-eabi)
compiled by GNU C version 9.4.0, GMP version 6.2.1, MPFR version 4.1.0,
MPC version 1.2.1, isl version isl-0.24-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 3261fde4c69fe46364115246804cccd4
COLLECT_GCC_OPTIONS='-v' '-c' '-Wall' '-Wextra' '-O3' '-mbig-endian'
'-ffreestanding' '-fbuiltin' '-nostdinc' '-save-temps' '-mcpu=cortex-a72' '-o'
'test.a72' '-mfloat-abi=soft' '-marm' '-mlibarch=armv8-a+crc'
'-march=armv8-a+crc'
/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/12.1.0/../../../../armeb-none-eabi/bin/as
-EB -march=armv8-a+crc -mfloat-abi=soft -meabi=5 -o test.a72 test.s
COMPILER_PATH=/home/gjimenez/x-tools/armeb-none-eabi/libexec/gcc/armeb-none-eabi/12.1.0/:/home/gjimenez/x-tools/armeb-none-eabi/libexec/gcc/armeb-none-eabi/12.1.0/:/home/gjimenez/x-tools/armeb-none-eabi/libexec/gcc/armeb-none-eabi/:/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/12.1.0/:/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/:/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/12.1.0/../../../../armeb-none-eabi/bin/
LIBRARY_PATH=/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/12.1.0/thumb/v8-a/nofp/:/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/12.1.0/../../../../armeb-none-eabi/lib/thumb/v8-a/nofp/:/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/12.1.0/:/home/gjimenez/x-tools/armeb-none-eabi/lib/gcc/armeb-none-eabi/12.1.0/../../../../armeb-none-eabi/lib/
COLLECT_GCC_OPTIONS='-v' '-c' '-Wall' '-Wextra' '-O3' '-mbig-endian'
'-ffreestanding' '-fbuiltin' '-nostdinc' '-save-temps' '-mcpu=cortex-a72' '-o'
'test.a72' '-mfloat-abi=soft' '-marm' '-mlibarch=armv8-a+crc'
'-march=armv8-a+crc' '-dumpdir' 'test.'
