Commit Graph

150 Commits

Author SHA1 Message Date
Eli Friedman 72a93e5e9b Add comment to clarify the behavior of a helper in DSE.
llvm-svn: 139571
2011-09-13 01:28:59 +00:00
Owen Anderson 58704ee442 Try again at r138809 (make DSE more aggressive in removing dead stores at the end of a function), now with less deleting stores before memcpy's.
llvm-svn: 139150
2011-09-06 18:14:09 +00:00
Owen Anderson e316e5b2ad Speculatively revert r138809 in an attempt to fix DragonEgg.
llvm-svn: 138829
2011-08-30 21:11:06 +00:00
Owen Anderson d708ec4c6a When walking backwards to eliminate final stores to allocas at the end of a function, encountering an unrelated store should not cause us to give up like encountering a load does.
llvm-svn: 138809
2011-08-30 18:51:55 +00:00
Eli Friedman 9a468153e1 Atomic load/store handling for the passes using memdep (GVN, DSE, memcpyopt).
llvm-svn: 137888
2011-08-17 22:22:24 +00:00
Eli Friedman 89b694b096 Misc mid-level changes for new 'fence' instruction.
llvm-svn: 136205
2011-07-27 01:08:30 +00:00
Chris Lattner 229907cd11 land David Blaikie's patch to de-constify Type, with a few tweaks.
llvm-svn: 135375
2011-07-18 04:54:35 +00:00
Eli Friedman 7d58bc7bc0 Add "unknown" results for memdep, which mean "I don't know whether a dependence for the given instruction exists in the given block". This cleans up all the existing hacks in memdep which represent this concept by returning clobber with various unrelated instructions.
llvm-svn: 133031
2011-06-15 00:47:34 +00:00
Chris Lattner 0ab5e2cded Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129558
2011-04-15 05:18:47 +00:00
Bill Wendling 5034159c5f * The DSE code that tested for overlapping needed to take into account the fact
that one of the numbers is signed while the other is unsigned. This could lead
  to a wrong result when the signed was promoted to an unsigned int.

* Add the data layout line to the testcase so that it will test the appropriate
  thing.

Patch by David Terei!

llvm-svn: 128577
2011-03-30 21:37:19 +00:00
Benjamin Kramer e41395ac24 DSE: Remove an early exit optimization that depended on the ordering of a SmallPtrSet.
Fixes PR9569 and will hopefully make selfhost on ASLR-enabled systems more deterministic.

llvm-svn: 128482
2011-03-29 20:28:57 +00:00
Bill Wendling b5139920d6 Simplification noticed by Frits.
llvm-svn: 128333
2011-03-26 09:32:07 +00:00
Bill Wendling 19f33b9393 Rework the logic that determines if a store completely overlaps an ealier store.
There are two ways that a later store can comletely overlap a previous store:

1. They both start at the same offset, but the earlier store's size is <= the
   later's size, or
2. The earlier store's offset is > the later's offset, but it's offset + size
   doesn't extend past the later's offset + size.

llvm-svn: 128332
2011-03-26 08:02:59 +00:00
Bill Wendling db40b5c899 PR9561: A store with a negative offset (via GEP) could erroniously say that it
completely overlaps a previous store, thus mistakenly deleting that store. Check
for this condition.

llvm-svn: 128319
2011-03-26 01:20:37 +00:00
Dan Gohman 0f124e1987 Give GetUnderlyingObject a TargetData, to keep it in sync
with BasicAA's DecomposeGEPExpression, which recently began
using a TargetData. This fixes PR8968, though the testcase
is awkward to reduce.

Also, update several off GetUnderlyingObject's users
which happen to have a TargetData handy to pass it in.

llvm-svn: 124134
2011-01-24 18:53:32 +00:00
Cameron Zwarich b703654edc Remove code for updating dominance frontiers and some outdated references to
dominance and post-dominance frontiers.

llvm-svn: 123725
2011-01-18 04:11:31 +00:00
Dan Gohman a4fcd2418d Move Value::getUnderlyingObject to be a standalone
function so that it can live in Analysis instead of
VMCore.

llvm-svn: 121885
2010-12-15 20:02:24 +00:00
Chris Lattner 4dc53e37d9 Use a stronger predicate here, pointed out by Duncan
llvm-svn: 121040
2010-12-06 21:48:10 +00:00
Chris Lattner ca335e38cf add some DEBUG statements.
llvm-svn: 121038
2010-12-06 21:13:51 +00:00
Chris Lattner 94fbdf3814 Fix PR8728, a miscompilation I recently introduced. When optimizing
memcpy's like:
  memcpy(A, B)
  memcpy(A, C)

we cannot delete the first memcpy as dead if A and C might be aliases.
If so, we actually get:

  memcpy(A, B)
  memcpy(A, A)

which is not correct to transform into:

  memcpy(A, A)

This patch was heavily influenced by Jakub Staszak's patch in PR8728, thanks
Jakub!

llvm-svn: 120974
2010-12-06 01:48:06 +00:00
Chris Lattner 903add84d9 Enhance DSE to handle the variable index case in PR8657.
llvm-svn: 120498
2010-11-30 23:43:23 +00:00
Chris Lattner c0f3379ae0 teach DSE to use GetPointerBaseWithConstantOffset to analyze
may-aliasing stores that partially overlap with different base
pointers.  This implements PR6043 and the non-variable part of
PR8657

llvm-svn: 120485
2010-11-30 23:05:20 +00:00
Chris Lattner 6712251f41 Make DeleteDeadInstruction be a static function, move some code around.
llvm-svn: 120471
2010-11-30 21:58:14 +00:00
Chris Lattner 51d67ce2ff switch RemoveAccessedObjects to use AliasAnalysis::Location to simplify
the code.  We now get accurate sizes on Loads, though it surely doesn't
matter in practice.

llvm-svn: 120469
2010-11-30 21:47:58 +00:00
Chris Lattner f80b39986f two improvements to RemoveAccessedObjects:
1. if the underlying pointer passed in can be resolved
   to any argument or alloca, then we don't need to scan.
   Previously we would only avoid the scan if the alloca
   or byval was actually considered dead.
2. The dead store processing code is itself completely
   dead and didn't handle volatile stores right anyway,
   so delete it.  This allows simplifying the interface
   to RemoveAccessedObjects.

llvm-svn: 120467
2010-11-30 21:38:30 +00:00
Chris Lattner 7fe08b67fa remove the "undead" terminology, which is nonstandard and never
made sense to me.  We now have a set of dead stack objects, and
they become live when loaded.  Fix a theoretical problem where
we'd pass in the wrong pointer to the alias query.

llvm-svn: 120465
2010-11-30 21:32:12 +00:00
Chris Lattner 127818d746 move call handling in handleEndBlock up a bit, and simplify it.
If the call might read all the allocas, stop scanning early.
Convert a vector to smallvector, shrink SmallPtrSet to 16 instead
of 64 to avoid crazy linear scans.

llvm-svn: 120463
2010-11-30 21:18:46 +00:00
Chris Lattner 60a8b3dab8 various cleanups and code simplification
llvm-svn: 120454
2010-11-30 19:48:15 +00:00
Chris Lattner 51c28a93cc make getPointerSize a static function. Add ivars to DSE for
AA and MD pass info instead of using getAnalysis<> all over.

llvm-svn: 120453
2010-11-30 19:34:42 +00:00
Chris Lattner 77d79fa25f reduce indentation, clean up TD use a bit.
llvm-svn: 120452
2010-11-30 19:28:23 +00:00
Chris Lattner b63ba73b1b enhance isRemovable to refuse to delete volatile mem transfers
now that DSE hacks on them.  This fixes a regression I introduced,
by generalizing DSE to hack on transfers.

llvm-svn: 120445
2010-11-30 19:12:10 +00:00
Chris Lattner 58b779e9c2 Rewrite the main DSE loop to be written in terms of reasoning
about pairs of AA::Location's instead of looking for MemDep's
"Def" predicate.  This is more powerful and general, handling
memset/memcpy/store all uniformly, and implementing PR8701 and
probably obsoleting parts of memcpyoptimizer.

This also fixes an obscure bug with init.trampoline and i8
stores, but I'm not surprised it hasn't been hit yet.  Enhancing
init.trampoline to carry the size that it stores would allow
DSE to be much more aggressive about optimizing them.

llvm-svn: 120406
2010-11-30 07:23:21 +00:00
Chris Lattner 3590ef817c rename a function and reduce some indentation, no functionality change.
llvm-svn: 120391
2010-11-30 05:30:45 +00:00
Chris Lattner 2227a8a192 rename doesClobberMemory -> hasMemoryWrite to be more specific, and
remove an actively-wrong comment.

llvm-svn: 120378
2010-11-30 01:37:52 +00:00
Chris Lattner 9d179d911d clean up handling of 'free', detangling it from everything else.
It can be seriously improved, but at least now it isn't intertwined
with the other logic.

llvm-svn: 120377
2010-11-30 01:28:33 +00:00
Chris Lattner 9a146372b5 Teach basicaa that memset's modref set is at worst "mod" and never
contains "ref".

Enhance DSE to use a modref query instead of a store-specific hack
to generalize the "ignore may-alias stores" optimization to handle
memset and memcpy.

llvm-svn: 120368
2010-11-30 00:28:45 +00:00
Chris Lattner c3c754f750 my previous patch would cause us to start deleting some volatile
stores, fix and add a testcase.

llvm-svn: 120363
2010-11-30 00:12:39 +00:00
Chris Lattner d4f1090948 two changes to DSE that shouldn't affect anything:
1. Don't bother trying to optimize:

lifetime.end(ptr)
store(ptr)

as it is undefined, and therefore shouldn't exist.

2. Move the 'storing a loaded pointer' xform up, simplifying
  the may-aliased store code.

llvm-svn: 120359
2010-11-30 00:01:19 +00:00
Chris Lattner 2e8793482c fix PR8677, patch by Jakub Staszak!
llvm-svn: 120325
2010-11-29 21:59:31 +00:00
Chris Lattner e48c31ce33 implement PR8576, deleting dead stores with intervening may-alias stores.
llvm-svn: 119927
2010-11-21 07:34:32 +00:00
Dan Gohman d4b7fff2e8 Enhance DSE to handle the case where a free call makes more than
one store dead. This is especially noticeable in
SingleSource/Benchmarks/Shootout/objinst.

llvm-svn: 118875
2010-11-12 02:19:17 +00:00
Dan Gohman f372cf869b Reapply r116831 and r116839, converting AliasAnalysis to use
uint64_t, plus fixes for places I missed before.

llvm-svn: 116875
2010-10-19 22:54:46 +00:00
Dan Gohman b4aa503501 Revert r116831 and r116839, which are breaking selfhost builds.
llvm-svn: 116858
2010-10-19 21:06:16 +00:00
Dan Gohman 896ac62346 Oops, check in all the files for converting AliasAnalysis to
use uint64_t.

llvm-svn: 116839
2010-10-19 18:08:27 +00:00
Owen Anderson 6c18d1aac0 Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor.  This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes.  Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin.  It is possible that there are problems
with the static dependencies that will only be visible with non-standard options.  If you encounter any crash in pass
registration/creation, please send the testcase to me directly.

llvm-svn: 116820
2010-10-19 17:21:58 +00:00
Dan Gohman 14fe8cf238 Consistently use AliasAnalysis::UnknownSize instead of hardcoding ~0u.
llvm-svn: 116815
2010-10-19 17:06:23 +00:00
Owen Anderson 8ac477ffb5 Begin adding static dependence information to passes, which will allow us to
perform initialization without static constructors AND without explicit initialization
by the client.  For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve.  I hope to be able to relax
the latter requirement in the future.

llvm-svn: 116334
2010-10-12 19:48:12 +00:00
Owen Anderson df7a4f2515 Now with fewer extraneous semicolons!
llvm-svn: 115996
2010-10-07 22:25:06 +00:00
Owen Anderson a7aed18624 Reapply r110396, with fixes to appease the Linux buildbot gods.
llvm-svn: 110460
2010-08-06 18:33:48 +00:00
Owen Anderson bda59bd247 Revert r110396 to fix buildbots.
llvm-svn: 110410
2010-08-06 00:23:35 +00:00