https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57073
--- Comment #17 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Thomas Koenig <[email protected]>: https://gcc.gnu.org/g:5b0da09f0ed5da80734c143d3ce2bacd78dc0c28 commit r17-1734-g5b0da09f0ed5da80734c143d3ce2bacd78dc0c28 Author: Thomas Koenig <[email protected]> Date: Mon Jun 22 07:26:25 2026 +0200 Optimize (-1.0)**n to (real) (1 - ((n & 1) << 1)). The problem was that the optimization done for PR 57073 uses powi and friends, so it only applied to default integer exponent. The test case has an integer(kind=8) exponent, which is is calculated by calling a gfortran library function. There are two possible approaches: One would be to convert all integer types to default integer (because only the lowest-value bit matters to the result) and call the right __builtin_powi function. However, the generated code is suboptimal, see PR 125919. I therefore chose the variant which currently generates the best code. This requires the change to the power_6.f90 test case. gcc/fortran/ChangeLog: PR fortran/125914 * trans-expr.cc (gfc_conv_power_op): Rewrite (-1.0)**n into (real) (1 - ((n & 1) << 1)). gcc/testsuite/ChangeLog: PR fortran/125914 * gfortran.dg/power_6.f90: Remove scans for powi. * gfortran.dg/power_10.f90: New test.
