[AArch64] PR84114: Avoid reassociating FMA
authorWilco Dijkstra <wdijkstr@arm.com>
Mon, 5 Mar 2018 14:40:55 +0000 (14:40 +0000)
committerWilco Dijkstra <wilco@gcc.gnu.org>
Mon, 5 Mar 2018 14:40:55 +0000 (14:40 +0000)
commitb5b33e113434be909e8a6d7b93824196fb6925c0
treefa0e943425147bcc2a1bec6d4cafc2027dba79e1
parent13b93d4b899bd7390429113d2ac98ec057a8c3d2
[AArch64] PR84114: Avoid reassociating FMA

As discussed in the PR, the reassociation phase runs before FMAs are formed
and so can significantly reduce FMA opportunities.  Although reassociation
could be switched off, it helps in many cases, so a better alternative is to
only avoid reassociation of floating point additions.  This fixes the testcase
and gives 1% speedup on SPECFP2017, fixing the performance regression.

    gcc/
PR tree-optimization/84114
* config/aarch64/aarch64.c (aarch64_reassociation_width)
Avoid reassociation of FLOAT_MODE addition.

From-SVN: r258248
gcc/ChangeLog
gcc/config/aarch64/aarch64.c