Consider for example the following two functions
f0(int value) => value == 0 ? ... : ...;
f1(List<int> list) => list[0] == 1 ? ... : ...;
before this change we would produce a `BoxInt64(value)` followed by
`StrictCompare` in `f0` and `UnboxInt64` followed by `EqualityCompare`
in `f1`. However the decisions should be reversed: when comparing
unboxed values we should lean on `EqualityCompare` and when
comparing boxed values when smis are involved we should lean
on `StrictCompare`.
This change adjusts specialization and canonicalization rules to achieve
that: we prefer to emit `EqualityCompare` when specializing and then
add rule to collapse it back into `StrictCompare` if we discover that
is going to be more optimal (e.g. allows to avoid boxing).
TEST=vm/dart/aot_prefer_equality_comparison_il_test
Cq-Include-Trybots: luci.dart.try:vm-aot-linux-release-x64-try,vm-aot-linux-debug-simarm_x64-try,vm-aot-linux-debug-x64-try,vm-aot-android-release-arm64c-try
Change-Id: I953a346f22702debc61b84b745d2a9fab58a9ca5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/324981
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
Vyacheslav Egorov
00d883f459