I noted in CL 38327 that the SSA test API felt a bit
clunky after the ssa.Func/ssa.Cache/ssa.Config refactoring,
and promised to clean it up once the dust settled.
The dust has settled.
Along the way, this CL fixes a potential latent bug,
in which the amd64 test context was used for all dummy Syslook calls.
The lone SSA test using the s390x context did not depend on the
Syslook context being correct, so the bug did not arise in practice.
Change-Id: If964251d1807976073ad7f47da0b1f1f77c58413
Reviewed-on: https://go-review.googlesource.com/38346
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Suggested by mdempsky in CL 38232.
This allows us to use the Frontend field
to associate frontend state and information
with a function.
See the following CL in the series for examples.
This is a giant CL, but it is almost entirely routine refactoring.
The ssa test API is starting to feel a bit unwieldy.
I will clean it up separately, once the dust has settled.
Passes toolstash -cmp.
Updates #15756
Change-Id: I71c573bd96ff7251935fce1391b06b1f133c3caf
Reviewed-on: https://go-review.googlesource.com/38327
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This makes ssa.Func, ssa.Cache, and ssa.Config fulfill
the roles laid out for them in CL 38160.
The only non-trivial change in this CL is how cached
values and blocks get IDs. Prior to this CL, their IDs were
assigned as part of resetting the cache, and only modified
IDs were reset. This required knowing how many values and
blocks were modified, which required a tight coupling between
ssa.Func and ssa.Config. To eliminate that coupling,
we now zero values and blocks during reset,
and assign their IDs when they are used.
Since unused values and blocks have ID == 0,
we can efficiently find the last used value/block,
to avoid zeroing everything.
Bulk zeroing is efficient, but not efficient enough
to obviate the need to avoid zeroing everything every time.
As a happy side-effect, ssa.Func.Free is no longer necessary.
DebugHashMatch and friends now belong in func.go.
They have been left in place for clarity and review.
I will move them in a subsequent CL.
Passes toolstash -cmp. No compiler performance impact.
No change in 'go test cmd/compile/internal/ssa' execution time.
Change-Id: I2eb7af58da067ef6a36e815a6f386cfe8634d098
Reviewed-on: https://go-review.googlesource.com/38167
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Make sure we don't do O(n^2) work to eliminate a chain
of n copies.
benchmark old ns/op new ns/op delta
BenchmarkCopyElim1-8 1418 1406 -0.85%
BenchmarkCopyElim10-8 5289 5162 -2.40%
BenchmarkCopyElim100-8 52618 41684 -20.78%
BenchmarkCopyElim1000-8 2473878 424339 -82.85%
BenchmarkCopyElim10000-8 269373954 6367971 -97.64%
BenchmarkCopyElim100000-8 31272781165 104357244 -99.67%
Change-Id: I680f906f70f2ee1a8615cb1046bc510c77d59284
Reviewed-on: https://go-review.googlesource.com/22535
Reviewed-by: Alexandru Moșoi <alexandru@mosoi.ro>
