Commit Graph

163 Commits

Author SHA1 Message Date
Pete Cooper
9e1154cf5b Reverted r152620 - DSE: Shorten memset when a later store overwrites the start of it. There were all sorts of buildbot issues
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151621 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-28 05:06:24 +00:00
Pete Cooper
a116623e06 DSE: Shorten memset when a later store overwrites the start of it
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151620 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-28 04:27:10 +00:00
Craig Topper
858143816d Convert assert(0) to llvm_unreachable
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149967 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-07 05:05:23 +00:00
Nick Lewycky
c9b98ad7a7 Fix infinite loop in DSE when deleting a free in a reachable loop that's also
trivially infinite.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146197 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-08 22:36:35 +00:00
Pete Cooper
de2e27cc52 Fixed deadstoreelimination bug where negative indices were incorrectly causing the optimisation to occur
Turns out long long + unsigned long long is unsigned.  Doh!

Fixes http://llvm.org/bugs/show_bug.cgi?id=11455

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145731 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-03 00:04:30 +00:00
Nick Lewycky
ae10dd2859 Merge isObjectPointerWithTrustworthySize with getPointerSize. Use it when
looking at the size of the pointee. Fixes PR11390!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144773 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-16 03:49:48 +00:00
Pete Cooper
c7e5a6a2c6 Fixed bug in DeadStoreElimination commit r144239
Size of data being pointed to wasn't always being checked so some small writes were killing big writes

Fixes <rdar://problem/10426753>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144312 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-10 20:22:08 +00:00
Pete Cooper
5ccb0825ed DeadStoreElimination can now trim the size of a store if the end of the store is dead.
Currently checks alignment and killing stores on a power of 2 boundary as this is likely
to trim the size of the earlier store without breaking large vector stores into scalar ones.

Fixes <rdar://problem/10140300>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144239 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-09 23:07:35 +00:00
Nick Lewycky
336b88dac8 Do simple cross-block DSE when we encounter a free statement. Fixes PR11240.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143808 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-05 10:48:42 +00:00
Daniel Dunbar
28eb1c5217 Speculatively revert "DeadStoreElimination can now trim the size of a store if
the end of it is dead.", which appears to break bootstrapping LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143668 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-04 00:48:26 +00:00
Pete Cooper
2d32b86543 DeadStoreElimination can now trim the size of a store if the end of it is dead.
Only currently done if the later store is writing to a power of 2 address or 
has the same alignment as the earlier store as then its likely to not break up
large stores into smaller ones

Fixes <rdar://problem/10140300>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143630 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-03 18:01:56 +00:00
Nick Lewycky
4d882aae2a A non-escaping malloc in the entry block is not unlike an alloca. Do dead-store
elimination on them too.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142735 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-22 21:59:35 +00:00
Eli Friedman
b414142036 Enhance the memdep interface so that users can tell the difference between a dependency which cannot be calculated and a path reaching the entry point of the function. This patch introduces isNonFuncLocal, which replaces isUnknown in some cases.
Patch by Xiaoyi Guo.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141896 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-13 22:14:57 +00:00
Eli Friedman
1582e7f1e2 Add comment to clarify the behavior of a helper in DSE.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139571 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 01:28:59 +00:00
Owen Anderson
81856f7313 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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139150 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 18:14:09 +00:00
Owen Anderson
54c4735db3 Speculatively revert r138809 in an attempt to fix DragonEgg.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138829 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-30 21:11:06 +00:00
Owen Anderson
6e4be237b0 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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138809 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-30 18:51:55 +00:00
Eli Friedman
56efe24431 Atomic load/store handling for the passes using memdep (GVN, DSE, memcpyopt).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137888 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-17 22:22:24 +00:00
Eli Friedman
8a552bb85a Misc mid-level changes for new 'fence' instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136205 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-27 01:08:30 +00:00
Chris Lattner
db125cfaf5 land David Blaikie's patch to de-constify Type, with a few tweaks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135375 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18 04:54:35 +00:00
Eli Friedman
a990e071f2 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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133031 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-15 00:47:34 +00:00
Chris Lattner
7a2bdde0a0 Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129558 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-15 05:18:47 +00:00
Bill Wendling
31d244ead5 * 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!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128577 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-30 21:37:19 +00:00
Benjamin Kramer
ec3f227820 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128482 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 20:28:57 +00:00
Bill Wendling
1a4d58af09 Simplification noticed by Frits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128333 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-26 09:32:07 +00:00
Bill Wendling
150c4a1a89 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128332 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-26 08:02:59 +00:00
Bill Wendling
e420449e80 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128319 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-26 01:20:37 +00:00
Dan Gohman
bd1801b555 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124134 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-24 18:53:32 +00:00
Cameron Zwarich
301278719b Remove code for updating dominance frontiers and some outdated references to
dominance and post-dominance frontiers.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123725 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-18 04:11:31 +00:00
Dan Gohman
5034dd318a Move Value::getUnderlyingObject to be a standalone
function so that it can live in Analysis instead of
VMCore.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121885 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 20:02:24 +00:00
Chris Lattner
29d8d6b039 Use a stronger predicate here, pointed out by Duncan
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121040 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-06 21:48:10 +00:00
Chris Lattner
a9d4da85d6 add some DEBUG statements.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121038 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-06 21:13:51 +00:00
Chris Lattner
cc10244d77 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!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120974 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-06 01:48:06 +00:00
Chris Lattner
3161ae1867 Enhance DSE to handle the variable index case in PR8657.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120498 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 23:43:23 +00:00
Chris Lattner
a04096580a 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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120485 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 23:05:20 +00:00
Chris Lattner
7c80c15a8b Make DeleteDeadInstruction be a static function, move some code around.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120471 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 21:58:14 +00:00
Chris Lattner
d8d35316de 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120469 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 21:47:58 +00:00
Chris Lattner
42cb684f8d 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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120467 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 21:38:30 +00:00
Chris Lattner
5fb0fb397c 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120465 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 21:32:12 +00:00
Chris Lattner
86dc6c08cf 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120463 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 21:18:46 +00:00
Chris Lattner
83d6759403 various cleanups and code simplification
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120454 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 19:48:15 +00:00
Chris Lattner
e3c611085e make getPointerSize a static function. Add ivars to DSE for
AA and MD pass info instead of using getAnalysis<> all over.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120453 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 19:34:42 +00:00
Chris Lattner
9801651193 reduce indentation, clean up TD use a bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120452 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 19:28:23 +00:00
Chris Lattner
55ee75d571 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120445 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 19:12:10 +00:00
Chris Lattner
cf82dc376a 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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120406 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 07:23:21 +00:00
Chris Lattner
bbdc3703a3 rename a function and reduce some indentation, no functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120391 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 05:30:45 +00:00
Chris Lattner
72987a2742 rename doesClobberMemory -> hasMemoryWrite to be more specific, and
remove an actively-wrong comment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120378 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 01:37:52 +00:00
Chris Lattner
1ab4285b72 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120377 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 01:28:33 +00:00
Chris Lattner
201d1e56bb 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120368 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 00:28:45 +00:00
Chris Lattner
184d1ba738 my previous patch would cause us to start deleting some volatile
stores, fix and add a testcase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120363 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 00:12:39 +00:00