[Bug middle-end/30568] New: -ftrapping-math should prevent folding/dead code stripping of some builtins

[geoffk at gcc dot gnu dot org]

This program:

#include <stdio.h>
#include <math.h>
#include <fenv.h>

main()
{
unsigned flags;

feclearexcept(FE_ALL_EXCEPT);
(void)acos(1.1);
flags = fetestexcept(FE_ALL_EXCEPT);

printf("(void)acos( %e ) gives flags 0x%8x\n", 1.1, flags & FE_ALL_EXCEPT);
}

when compiled with -ftrapping-math, should show that some flags are set,
FE_INVALID I think (maybe others).  Instead it shows that no flags are set,
because GCC has completely folded out the call to acos().


-- 
           Summary: -ftrapping-math should prevent folding/dead code
                    stripping of some builtins
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: geoffk at gcc dot gnu dot org
GCC target triplet: *-*-darwin*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30568