There are no values other than instructions that can use other values. BBArguments are
defs, not uses. This eliminates a bunch of casts in clients that use getUser().
Swift SVN r9701
us to diagnose things that span multiple blocks, e.g.:
var xu8_3 : UInt8 = 240 // Global (cross block) analysis.
for i in 0..10 {}
xu8_3 += 40 // expected-error {{arithmetic operation '240 + 40' (on type 'UInt8') results in an overflow}}
This doesn't do full SSA construction in that it won't generate "phi" nodes, but will promote any loads that can be substituted with a (potentially field sensitive and decomposed) single value. Given that no diagnostics passes are going to be looking through BB args anyway, this seems like the right level of sophistication for definite init.
Swift SVN r9523
exploding them on demand. This finally resolves rdar://15170149,
which allows a bunch of tests in SILPasses/constant_propagation.swift
to work.
Swift SVN r9346
- Enhance the driver of definite initialization to scalarize copyaddrs
that span multiple tuple elements so that DI can only thing of a single
element at a time (when it comes to copy_addrs - inout and escapes can
span anything of course)
- Teach load eliminate to explode copyaddrs into its components when
doing so would allow eliminating a load.
- Fix a bug where indexing into a tuple inside an enum could cause
accesses to be attributed to the wrong element, which manifested
as a crash on the testsuite now that DI is being more aggressive.
Unfortunately, DI is now exploding some copyaddrs that feed inout shadows,
disabling the inout shadow optimization on something important for
stdlib/String.swift. This is a regression, but is less important than
unblocking work dependent on rdar://15170149, so I'm just dialing back
the testcase and tracking this with rdar://15228172.
Swift SVN r9345
Previously, the definite init pass would check to see if there was a
load available to optimize out the load of a non-trivial assign. Now
we just unconditionally lower an assign to a load/copy/store sequence,
and lead later load elimination zap the load if it is redundant.
This allows us to remove the old mechanics for doing reasoning about
load elimination, including all the "AccessPath" stuff.
Swift SVN r9340
into SSA form, moving to resolving rdar://15170149.
Instead of promoting loads in the middle of the process of proving
that everything passes DI requirements, do this after a full element
is ok.
Doing this requires changing just about everything about how we modeled
elements and subelements being promoted, but this is good for a lot of
reasons:
1) we now don't eagerly scalarize all loads to struct members, now we
just scalarize top-level tuples. This is good for preserving higher
level operations.
2) Even without scalarization, we can still model things at an extremely
fine grain, but we can also keep aggregate operations together.
This means that load promotion doesn't insert a kajillion
struct_extract + struct sequences to decompose then recompose things.
This is just patch #1 of a series, but this is the bulk of the hard work.
Swift SVN r9338
set. This is the last fix required to get copy_addr to forward to the
load in this trivial example from rdar://15170149:
func testTrivial(a : @inout Int) -> Int {
return a
}
on to more testing.
Swift SVN r9167
pass to be -definite-init instead of -memory-promotion, rename the
entrypoint for the pass to match, and tidy various and sundry comments.
Swift SVN r8927
