https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71869
Bug ID: 71869
Summary: __builtin_isgreater raises an invalid exception on
PPC64 using __float128 inputs.
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: murphyp at linux dot vnet.ibm.com
Target Milestone: ---
#include <fenv.h>
volatile __float128 qnan = __builtin_nanq("");
int main()
{
feclearexcept(FE_INVALID);
if (__builtin_isgreater(1.0Q, qnan)) puts("isgreater is broken");
if (fetestexcept(FE_INVALID)) puts("invalid wrongly set for quiet
comparison");
return 0;
}
Using a recent gcc-6-branch checkout:
gcc -mfloat128 -mcpu=power8
I assume this also the case for the other __builtin_is{ordering} functions too.
This causes a substantial number of test failures for float128 when shoehorned
into the glibc libm test suite. (Note, this is much hacked up local copy of
glibc to verify the compiler support for float128 is sufficient for glibc).
x86 appears to stick a call to __unordtf2 before attempting to call the
comparison function. I assume PPC64 should be doing a similar for KFmode.
