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Subject: [Bug middle-end/57073] __builtin_powif (-1.0, k) should be optimized to "1.0 - 2.0 * (K%2)"
Date: Thu, 30 May 2013 15:33:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57073

--- Comment #11 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Created attachment 30228
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30228&action=edit
Yet another patch that doesn't work

This one fails with

 program main
 ^
_24 = i_1 & 1;
power_6.f90:4:0: internal compiler error: verify_gimple failed
0x98ca4c verify_gimple_in_cfg(function*)
        ../../trunk/gcc/tree-cfg.c:4792
0x8c4d87 execute_function_todo
        ../../trunk/gcc/passes.c:1969
0x8c56e7 execute_todo
        ../../trunk/gcc/passes.c:2002

We have a few alternatives now:

1. This doesn't get fixed at all
2. This doesn't get fixed by me
3. This gets fixed in the Fortran front end
4. Somebody points out where my patch is going wrong, and helps me
   understant a bit more of the basics of GIMPLE.