Fixes a potential real bug in the case that SinkAddressProjections moves
projections without notifying SimplifyCFG of the change. This could
fail to update Analyses (probably won't break anything in practice).
Introduce SILInstruction::isPure. Among other things, this can tell
you if it's safe to duplicate instructions at their
uses. SinkAddressProjections should check this before sinking uses. I
couldn't find a way to expose this as a real bug, but it is a
theoretical bug.
Add the SinkAddressProjections functionality to the BasicBlockCloner
utility. Enable address projection sinking for all BasicBlockCloner
clients (the four different kinds of jump-threading that use it). This
brings the compiler much closer to banning all address phis.
The "bugs" were originally introduced a week ago here:
commit f22371bf0b (fork/fix-address-phi, fix-address-phi)
Author: Andrew Trick <atrick@apple.com>
Date: Tue Sep 17 16:45:51 2019
Add SIL SinkAddressProjections utility to avoid address phis.
Enable this utility during jump-threading in SimplifyCFG.
Ultimately, the SIL verifier should prevent all address-phis and we'll
need to use this utility in a few more places.
Fixes <rdar://problem/55320867> SIL verification failed: Unknown
formal access pattern: storage
Requested by gottesmm during review.
Update the variable naming conventions to lower-camel.
Run clang-format.
I'm sure I missed some local variables somewhere--this was a best
effort.
The XXOptUtils.h convention is already established and parallels
the SIL/XXUtils convention.
New:
- InstOptUtils.h
- CFGOptUtils.h
- BasicBlockOptUtils.h
- ValueLifetime.h
Removed:
- Local.h
- Two conflicting CFG.h files
This reorganization is helpful before I introduce more
utilities for block cloning similar to SinkAddressProjections.
Move the control flow utilies out of Local.h, which was an
unreadable, unprincipled mess. Rename it to InstOptUtils.h, and
confine it to small APIs for working with individual instructions.
These are the optimizer's additions to /SIL/InstUtils.h.
Rename CFG.h to CFGOptUtils.h and remove the one in /Analysis. Now
there is only SIL/CFG.h, resolving the naming conflict within the
swift project (this has always been a problem for source tools). Limit
this header to low-level APIs for working with branches and CFG edges.
Add BasicBlockOptUtils.h for block level transforms (it makes me sad
that I can't use BBOptUtils.h, but SIL already has
BasicBlockUtils.h). These are larger APIs for cloning or removing
whole blocks.
