The following problem was seen in a testcase under discussion in PR 30634:
# cat yy.c
#include <stdio.h>
double f(void)
{
long long t = 0x000fffffffffffff;
double t1;
__builtin_memcpy(&t1, &t, sizeof(long long));
return t1;
}
int main()
{
union
{
long long ll;
double d;
} u;
u.d = f ();
printf ("ll = 0x%llx\n", u.ll);
return 0;
}
# ../../xgcc -B../../ -O2 -o yy yy.c
# ./yy
ll = 0xffffffff000fffff
# ../../xgcc -B../../ -O0 -o yy yy.c
# ./yy
ll = 0xfffffffffffff
# ../../xgcc -B../../ -v
Reading specs from ../../specs
Target: hppa64-hp-hpux11.00
Configured with: ../gcc/configure --with-gnu-as --with-as=/opt/gnu64/bin/as
--with-ld=/usr/ccs/bin/ld --enable-shared --with-local-prefix=/opt/gnu64
--prefix=/opt/gnu64/gcc/gcc-4.2.0 --host=hppa64-hp-hpux11.00 --disable-nls
--with-gmp=/opt/gnu64/gcc/gcc-4.2.0
Thread model: posix
gcc version 4.2.0 20070123 (prerelease)
The constant 0x000fffffffffffff appears in the assembler output as a
pair of 32-bit .word values. The values are reversed when the testcase
is compiled at -O2. This doesn't appear to be a target issue since the
target only defines directives for the output of constants.
--
Summary: Incorrect constant generation for long long
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: danglin at gcc dot gnu dot org
GCC build triplet: hppa64-hp-hpux11.00
GCC host triplet: hppa64-hp-hpux11.00
GCC target triplet: hppa64-hp-hpux11.00
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30704
