https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69087
Bug ID: 69087
Summary: e500v2 cross compiler skips assignment of double local
variable in large stack frame
Product: gcc
Version: 4.2.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: mavik at outlook dot com.au
Target Milestone: ---
Created attachment 37192
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37192&action=edit
Preprocessed file
When compiled for a e500v2 target, the following program works as expected with
values of N in the ranges 1..4095 and 8192..8223. For values of N 4096..8191 or
greater than 8224 the output is either 0 or a random/uninitialised value. I
suspected that the issue was due to a stack overflow, however, when inspecting
the generated assembly code, for values of N 4096..8191 the assembly code
corresponding to the line "array[N-1] = N;" is omitted.
test.c
-----
#include <stdio.h>
int main(int argc, char *argv[])
{
double array[N];
array[N-1] = N;
printf("array[%d] = %f\n", N-1, array[N-1]);
return 1;
}
-----
Compiler details and building on the host:
$ /opt/Denx/eldk/usr/bin/ppc_85xxDP-gcc -v -save-temps -DN=4096 test.c
Reading specs from /opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/specs
Target: powerpc-linux
Configured with:
/opt/eldk/build/ppc-2008-04-01/work/usr/src/denx/BUILD/crosstool-0.43/build/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/gcc-4.2.2/configure
--target=powerpc-linux --host=i686-host_pc-linux-gnu
--prefix=/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux
--disable-hosted-libstdcxx
--with-headers=/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/powerpc-linux/include
--with-local-prefix=/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/powerpc-linux
--disable-nls --enable-threads=posix --enable-symvers=gnu --enable-__cxa_atexit
--enable-languages=c,c++,java --enable-shared --enable-c99 --enable-long-long
--without-x
Thread model: posix
gcc version 4.2.2
/opt/Denx/eldk/usr/bin/../libexec/gcc/powerpc-linux/4.2.2/cc1 -E -quiet -v
-imultilib m8540 -iprefix
/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/ -D__unix__
-D__gnu_linux__ -D__linux__ -Dunix -D__unix -Dlinux -D__linux -Asystem=linux
-Asystem=unix -Asystem=posix -DN=4096 test.c -mcpu=8540 -mfloat-gprs=double
-mspe=yes -mabi=spe -fpch-preprocess -o test.i
ignoring nonexistent directory
"/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/../../../../powerpc-linux/sys-include"
ignoring nonexistent directory
"/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/../../../../powerpc-linux/include"
ignoring nonexistent directory
"/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/lib/gcc/powerpc-linux/4.2.2/include"
ignoring nonexistent directory
"/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/powerpc-linux/sys-include"
ignoring nonexistent directory
"/var/tmp/eldk.UZpAG7/usr/crosstool/gcc-4.2.2-glibc-20070515T2025-eldk/powerpc-linux/powerpc-linux/include"
ignoring duplicate directory
"/opt/Denx/eldk/usr/lib/gcc/powerpc-linux/4.2.2/include"
ignoring nonexistent directory
"/opt/Denx/eldk/usr/lib/gcc/powerpc-linux/4.2.2/../../../../powerpc-linux/sys-include"
ignoring nonexistent directory
"/opt/Denx/eldk/usr/lib/gcc/powerpc-linux/4.2.2/../../../../powerpc-linux/include"
#include "..." search starts here:
#include <...> search starts here:
/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/include
/opt/Denx/eldk/usr/../ppc_85xxDP/usr/include
End of search list.
/opt/Denx/eldk/usr/bin/../libexec/gcc/powerpc-linux/4.2.2/cc1 -fpreprocessed
test.i -quiet -dumpbase test.c -mcpu=8540 -mfloat-gprs=double -mspe=yes
-mabi=spe -auxbase test -version -o test.s
GNU C version 4.2.2 (powerpc-linux)
compiled by GNU C version 2.96 20000731 (Red Hat Linux 7.3 2.96-113).
GGC heuristics: --param ggc-min-expand=98 --param ggc-min-heapsize=128253
Compiler executable checksum: 1aec0482efbebeb41ccfcf839ce71331
/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/../../../../powerpc-linux/bin/as
-me500 -mspe -V -Qy -o test.o test.s
GNU assembler version 2.17.50.0.12 (powerpc-linux) using BFD version
2.17.50.0.12 20070128
/opt/Denx/eldk/usr/bin/../libexec/gcc/powerpc-linux/4.2.2/collect2
--eh-frame-hdr -V -Qy -m elf32ppclinux --hash-style=gnu -dynamic-linker
/lib/ld.so.1 /opt/Denx/eldk/usr/../ppc_85xxDP/usr/lib/crt1.o
/opt/Denx/eldk/usr/../ppc_85xxDP/usr/lib/crti.o
/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/m8540/crtbegin.o
-L/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/m8540
-L/opt/Denx/eldk/usr/lib/gcc/powerpc-linux/4.2.2/m8540
-L/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2
-L/opt/Denx/eldk/usr/bin/../lib/gcc
-L/opt/Denx/eldk/usr/lib/gcc/powerpc-linux/4.2.2
-L/opt/Denx/eldk/usr/../ppc_85xxDP/lib
-L/opt/Denx/eldk/usr/../ppc_85xxDP/usr/lib test.o -lgcc --as-needed -lgcc_s
--no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed
/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/m8540/crtsavres.o
/opt/Denx/eldk/usr/bin/../lib/gcc/powerpc-linux/4.2.2/m8540/crtend.o
/opt/Denx/eldk/usr/../ppc_85xxDP/usr/lib/crtn.o
GNU ld version 2.17.50.0.12 20070128
Supported emulations:
elf32ppclinux
elf32ppc
elf32ppcsim
$
Running on the target:
#./a.out
array[4095] = -0.208637
#
The block of assembly that gets omitted is of the form:
-----
6:test.c **** array[N-1] = N;
40 .loc 1 6 0
41 0034 3D200000 lis 9,.LC0@ha
42 0038 39290010 la 9,.LC0@l(9)
43 003c 10090301 evldd 0,0(9)
44 0040 39207FF8 li 9,32760
45 0044 101F4B20 evstddx 0,31,9
-----
I haven't yet run the test with a later version of the cross compiler as
configuring the tool chain is non-trivial and it may not be possible to upgrade
for this particular product. But I will give it a go anyway.
