Commit Graph

249 Commits

Author SHA1 Message Date
Rafael Espindola
5465c9422f Don't call dominates on unreachable instructions. Should fix the dragonegg
build. Testcase is still reducing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151474 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-26 05:30:08 +00:00
Kostya Serebryany
0ca032b03d The patch resolves the conflict between AddressSanitizer and load widening (GVN).
The problem initially reported by Mozilla folks (http://code.google.com/p/address-sanitizer/issues/detail?id=20),
but it also prevents us from enabling LLVM bootstrap with AddressSanitizer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149925 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-06 22:48:56 +00:00
David Blaikie
4d6ccb5f68 More dead code removal (using -Wunreachable-code)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148578 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-20 21:51:11 +00:00
Nick Lewycky
b48a18903a Change CaptureTracking to pass a Use* instead of a Value* when a value is
captured. This allows the tracker to look at the specific use, which may be
especially interesting for function calls.

Use this to fix 'nocapture' deduction in FunctionAttrs. The existing one does
not iterate until a fixpoint and does not guarantee that it produces the same
result regardless of iteration order. The new implementation builds up a graph
of how arguments are passed from function to function, and uses a bottom-up walk
on the argument-SCCs to assign nocapture. This gets us nocapture more often, and
does so rather efficiently and independent of iteration order.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147327 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-28 23:24:21 +00:00
Nick Lewycky
9f47fb6637 Fix crasher in GVN due to my recent capture tracking changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145047 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-21 19:42:56 +00:00
Nick Lewycky
7912ef97ff Less template, more virtual! Refactoring suggested by Chris in code review.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145014 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-20 19:37:06 +00:00
Nick Lewycky
173862e546 Refactor code to use new attribute getters on CallSite for NoCapture and ByVal.
Suggested in code review by Eli.

That code in InstCombine looks kinda suspicious.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145013 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-20 19:09:04 +00:00
Nick Lewycky
88990248d3 Refactor capture tracking (which already had a couple flags for whether returns
and stores capture) to permit the caller to see each capture point and decide
whether to continue looking.

Use this inside memdep to do an analysis that basicaa won't do. This lets us
solve another devirtualization case, fixing PR8908!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144580 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-14 22:49:42 +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
667ccf231b Misc analysis passes that need to be aware of atomic load/store.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137650 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-15 20:54:19 +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
992205ac71 Add a limit to the number of instructions memdep will scan in a single block. This prevents (at least in some cases) O(N^2) runtime in passes like DSE.
The limit in this patch is probably too high, but it is enough to stop DSE from going completely insane on a testcase I have (which has a single block with around 50,000 non-aliasing stores in it).

rdar://9471075



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133111 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-15 23:59:25 +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
Dan Gohman
a3351a0e5d Disable the main feature of 130180, the elimination of loads that are
redundant with partially-aliasing loads.

When computing what portion of a clobbering load value is needed,
it doesn't consider phi-translation which may have occurred
between the clobbing load and the redundant load.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132631 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-04 06:48:50 +00:00
Eli Friedman
7c6a5a2c39 When marking a block as being unanalyzable, use "Clobber" on the terminator instead of the first instruction in the block. This is a bit of a hack; "Clobber" isn't really the right marking in the first place. memdep doesn't really have any way of properly expressing "unanalyzable" at the moment. Using it on the terminator is much less ambiguous than using it on an arbitrary instruction, though.
In the given testcase, the "Clobber" was pointing to a load, and GVN was incorrectly assuming that meant that the "Clobber" load overlapped the load being analyzed (when they are actually unrelated).

The included testcase tests both this commit and r132434.

Part two of rdar://9429882.  (r132434 was mislabeled.)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132442 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-02 00:08:52 +00:00
Eli Friedman
fc09797426 In MemoryDependenceAnalysis::getNonLocalPointerDepFromBB, if a given block is is deemed unanalyzable (and we execute one of the "goto PredTranslationFailure" statements), make sure we don't put information about the predecessors of that block into the returned data structures; this can lead to, among other things, extraneous results (which will confuse passes using memdep). Fixes an assert in GVN compiling ruby. Part of rdar://problem/9521954 .
Testcase coming up soon.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132434 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-01 23:16:53 +00:00
Owen Anderson
e1edb17bc3 @llvm.lifetime.begin acts as a load, not @llvm.lifetime.end.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131437 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-17 00:05:49 +00:00
Chris Lattner
4034e14985 teach GVN to widen integer loads when they are overaligned, when doing an
wider load would allow elimination of subsequent loads, and when the wider
load is still a native integer type.  This eliminates a ton of loads on 
various benchmarks involving struct fields, though it is somewhat hobbled
by clang not being very aggressive about field alignment.

This is yet another step along the way towards resolving PR6627.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130390 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-28 07:29:08 +00:00
Chris Lattner
cb5fd743a9 Enhance memdep to return clobber relation between noalias loads when
an earlier load could be widened to encompass a later load.  For example,
if we see:

  X = load i8* P, align 4
  Y = load i8* (P+3), align 1

and we have a 32-bit native integer type, we can widen the former load
to i32 which then makes the second load redundant.  GVN can't actually
do anything with this load/load relation yet, so this isn't testable, but 
it is the next step to resolving PR6627, and a fairly general class of 
"merge neighboring loads" missed optimizations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130250 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-26 22:42:01 +00:00
Chris Lattner
d5c7f7cb5e use AA::isMustAlias to simplify some calls.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130248 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-26 21:53:34 +00:00
Chris Lattner
130131ea78 remove support for llvm.invariant.end from memdep. It is a
work-in-progress that is not progressing, and it has issues.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130247 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-26 21:50:51 +00:00
Chris Lattner
1f821512fc Enhance MemDep: When alias analysis returns a partial alias result,
return it as a clobber.  This allows GVN to do smart things.

Enhance GVN to be smart about the case when a small load is clobbered
by a larger overlapping load.  In this case, forward the value.  This
allows us to compile stuff like this:

int test(void *P) {
  int tmp = *(unsigned int*)P;
  return tmp+*((unsigned char*)P+1);
}

into:

_test:                                  ## @test
	movl	(%rdi), %ecx
	movzbl	%ch, %eax
	addl	%ecx, %eax
	ret

which has one load.  We already handled the case where the smaller
load was from a must-aliased base pointer.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130180 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-26 01:21:15 +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
Jakob Stoklund Olesen
f7624bc6dd Revert r123207: "Turn on memdep's verifyRemoved() in an attempt to smoke out the cause of our gcc bootstrap miscompare."
It didn't.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123215 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 04:05:39 +00:00
Jakob Stoklund Olesen
121704d738 Turn on memdep's verifyRemoved() in an attempt to smoke out the cause of our gcc bootstrap miscompare.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123207 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 01:18:03 +00:00
Jeffrey Yasskin
8e68c38735 Change all self assignments X=X to (void)X, so that we can turn on a
new gcc warning that complains on self-assignments and
self-initializations.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122458 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-23 00:58:24 +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
Dan Gohman
2cd1952917 Update memdep to handle PartialAlias as MayAlias.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121723 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13 22:47:57 +00:00
Chris Lattner
12bf43bc4f strength reduce this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120381 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-30 01:56:13 +00:00
Benjamin Kramer
dd061b2854 Initialize MemDep's TD member so buildbots don't trip over an uninitialized pointer (TD is passed to PHITransAddr).
I wonder why this didn't explode earlier.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119944 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-21 15:21:46 +00:00
Chris Lattner
f6f1f062cc implement PR8576, deleting dead stores with intervening may-alias stores.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119927 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-21 07:34:32 +00:00
Dan Gohman
6d8eb156e6 Add helper functions for computing the Location of load, store,
and vaarg instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118845 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-11 21:50:19 +00:00
Dan Gohman
8a66a202f6 It's not necessary to clear out the Size and TBAATag at each of
these points.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118752 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-11 00:42:22 +00:00
Dan Gohman
ec9b4ac914 Set NonLocalDepInfo's Size field to UnknownSize when invalidating
it, so that it doesn't appear to be a known size.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118748 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-11 00:20:27 +00:00
Dan Gohman
2365f08c7d When clearing a non-local pointer dependency cache entry, clear
the reverse map too. This fixes seflhost build errors.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118729 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 22:35:02 +00:00
Dan Gohman
533c2ad360 Factor out the code for computing an AliasAnalysis::Location
for a given instruction into a helper function.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118723 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 21:51:35 +00:00
Dan Gohman
733c54da1e Fully invalidate cached results when a prior query's size or
type is insufficient for, or incompatible with, the current query.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118721 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 21:45:11 +00:00
Dan Gohman
075fb5d68f Enhance GVN to do more precise alias queries for non-local memory
references. For example, this allows gvn to eliminate the load in
this example:

  void foo(int n, int* p, int *q) {
    p[0] = 0;
    p[1] = 1;
    if (n) {
      *q = p[0];
    }
  }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118714 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 20:37:15 +00:00
Dan Gohman
cd5c123a1d Teach memdep to use pointsToConstantMemory to determine that loads
from constant memory don't alias any stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117636 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 01:14:04 +00:00
Owen Anderson
081c34b725 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116820 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-19 17:21:58 +00:00
Owen Anderson
2ab36d3502 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116334 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-12 19:48:12 +00:00
Owen Anderson
ce665bd2e2 Now with fewer extraneous semicolons!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115996 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 22:25:06 +00:00
Dan Gohman
c1ac0d7623 Teach memdep about TBAA tags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114588 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-22 21:41:02 +00:00
Chris Lattner
09981982f1 cleanup some of the lifetime/invariant marker stuff, add a big fixme.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113144 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-06 03:58:04 +00:00
Chris Lattner
c5a5cf26fd speed up -gvn 3.4% on the testcase in PR7023
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113135 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-06 01:26:29 +00:00
Owen Anderson
90c579de5a Reapply r110396, with fixes to appease the Linux buildbot gods.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110460 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 18:33:48 +00:00
Owen Anderson
1f74590e9d Revert r110396 to fix buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110410 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 00:23:35 +00:00
Owen Anderson
9ccaf53ada Don't use PassInfo* as a type identifier for passes. Instead, use the address of the static
ID member as the sole unique type identifier.  Clean up APIs related to this change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110396 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-05 23:42:04 +00:00
Dan Gohman
5fa417c790 Fix memdep's code for reasoning about dependences between two calls. A Ref
response from getModRefInfo is not useful here. Instead, check for identical
calls only in the NoModRef case.

Reapply r110270, and strengthen it to compensate for the memdep changes.
When both calls are readonly, there is no dependence between them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110382 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-05 22:09:15 +00:00
Dan Gohman
847a84efd2 Add a convenient form of AliasAnalysis::alias for the case where the sizes
are unknown.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110090 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-03 00:56:30 +00:00