[Bug middle-end/84309] [8 Regression] Wrong-code with -ffast-math

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84309

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Tue Feb 13 08:34:42 2018
New Revision: 257617

URL: https://gcc.gnu.org/viewcvs?rev=257617&root=gcc&view=rev
Log:
        PR middle-end/84309
        * match.pd (pow(C,x) -> exp(log(C)*x)): Optimize instead into
        exp2(log2(C)*x) if C is a power of 2 and c99 runtime is available.
        * generic-match-head.c (canonicalize_math_after_vectorization_p): New
        inline function.
        * gimple-match-head.c (canonicalize_math_after_vectorization_p): New
        inline function.
        * omp-simd-clone.h: New file.
        * omp-simd-clone.c: Include omp-simd-clone.h.
        (expand_simd_clones): No longer static.
        * tree-vect-patterns.c: Include fold-const-call.h, attribs.h,
        cgraph.h and omp-simd-clone.h.
        (vect_recog_pow_pattern): Optimize pow(C,x) to exp(log(C)*x).
        (vect_recog_widen_shift_pattern): Formatting fix.
        (vect_pattern_recog_1): Don't check optab for calls.

        * gcc.dg/pr84309.c: New test.
        * gcc.target/i386/pr84309.c: New test.

Added:
    trunk/gcc/omp-simd-clone.h
    trunk/gcc/testsuite/gcc.dg/pr84309.c
    trunk/gcc/testsuite/gcc.target/i386/pr84309.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/generic-match-head.c
    trunk/gcc/gimple-match-head.c
    trunk/gcc/match.pd
    trunk/gcc/omp-simd-clone.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vect-patterns.c