tree 9f00505621fb4502293083163a4bcba6f83b1c07
parent 89e43b414187a5e5ed03bddc40156053b043b9f5
author Vyacheslav Egorov <vegorov@google.com> 1525701370 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1525701370 +0000

Revert "[VM] Reduce Smi size to 32 bit on 64 bit platforms"

This reverts commit cf78da8a48b886cbd70e6c50dd7461a621065e31.

Reason for revert: introduces significant performance regression (~30%) on analyzer benchmarks (warm-analysis) without clearly visible hot-spot.

Original change's description:
> [VM] Reduce Smi size to 32 bit on 64 bit platforms
> 
> This reduces small tagged integers on 64 bit platforms from 63 bits to
> 31 bits plus one tag bit.
> This is a step on the way to compile-time-optional compressed pointers
> on 64 bit platforms.  See more about this at go/dartvmlearnings
> This causes a slowdown for some uses of integers that don't fit in 31
> signed bits, but because both x64 and ARM64 have unboxed 64 bit
> integers now the performance hit should not be too bad.
> 
> This is a reapplication of
> https://dart-review.googlesource.com/c/sdk/+/46244
> It was reverted due to a compilation error on 32 bit
> ARM with DBC.
> 
> R=​vegorov@google.com
> 
> Change-Id: I943de1768519457f0e5a61ef0b4ef204b6a53281
> Reviewed-on: https://dart-review.googlesource.com/51321
> Reviewed-by: Vyacheslav Egorov <vegorov@google.com>

TBR=vegorov@google.com,erikcorry@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I8c5b909ec38663b5f5b05f69ef488c97341f8f3d
Reviewed-on: https://dart-review.googlesource.com/54000
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>