commit 45217376b527cd17d758152c54960e6786288e31
author Evgeny Astigeevich <evgeny.astigeevich@linaro.org> Wed Apr 03 10:46:13 2019 +0100
committer Treehugger Robot <treehugger-gerrit@google.com> Tue Oct 29 15:40:27 2019 +0000
tree cc2ae731f7ebfe61af74fa8150025064a0245a8a
parent 8b236fac816beb18e4919e2c4260da843257a4e3

Fix intersecting live ranges created by instruction scheduler

When scheduling code like the following:
LOOP:
   v2=phi(v0, v1)
   use(v2)
   v1=...
   goto LOOP

the instruction scheduler can move 'v1=...' before 'use(v2)'. This
causes live ranges of v1 and v2 to intersect and results to a MOV
instruction to be created.

The CL fixes this.

Improvements, Pixel3:
  Little CPU, arm64
    micro/GCCLoops
      Example12       14.1%
      Example10b      11.0%
      Example23       8.1%
      Example24       6.6%
      Example10a      5.0%
    FFT workload      4.7%
    Compress workload 1.2%

  Little CPU, arm32
    micro/GCCLoops
      Example23         7.5%
      Example24         4.3%
    MonteCarlo workload 1.35%

  Big CPU, arm32 and arm64
    No significant improvements

No significant regressions (> 5%) are found.

Test: test.py --host --optimizing --jit --gtest
Test: test.py --target --optimizing --jit
Test: run-gtests.sh
Change-Id: I1e4282af18f2d51fde5325a0c00a57e8bbc4fbed