http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46399
Summary: Missing type promotion for library call argument
Product: gcc
Version: 4.4.3
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: middle-end
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: kreb...@gcc.gnu.org
The following testcase produces an unexpected result when compiled with:
gcc -O3 t.c -ot
int
main ()
{
volatile _Decimal32 b, c;
volatile unsigned int ui;
volatile long long sll;
ui = 1;
sll = 1LL;
b = sll;
c = ui;
printf("b: %x\n", *(int*)&b);
printf("c: %x\n", *(int*)&c);
}
./t:
b: 22500001
c: 3a95e225
The problem appears to be a missing type promotion when doing the conversion
from unsigned int to _Decimal32 in c = ui:
stmg %r14,%r15,112(%r15)
aghi %r15,-184
lhi %r1,1
st %r1,180(%r15)
lghi %r1,1
stg %r1,160(%r15)
lg %r2,160(%r15) <-- load a 64bit value into r2
brasl %r14,__dpd_floatdisd
ste %f0,172(%r15)
l %r2,180(%r15) <-- load a 32bit value into r2
brasl %r14,__dpd_floatunssisd without zero extending to 64bit
....
When I manually kill the upper 32 bits of r2 before doing the second lib call
it works fine:
stmg %r14,%r15,112(%r15)
aghi %r15,-184
.cfi_offset 15, -40
.cfi_offset 14, -48
.cfi_def_cfa_offset 344
lhi %r1,1
st %r1,180(%r15)
lghi %r1,1
stg %r1,160(%r15)
lg %r2,160(%r15)
brasl %r14,__dpd_floatdisd
ste %f0,172(%r15)
lghi %r2,0 <-- load a 64bit 0 into r2
l %r2,180(%r15)
brasl %r14,__dpd_floatunssisd
...
The result then is:
b: 22500001
c: 22500001
The testcase above is extracted from gcc.dg/dfp/pr41049.c which currently seems
to fail due to that problem on s390*.
