Commit Graph

302 Commits

Author SHA1 Message Date
Chandler Carruth
b1adb88d05 Jump through some silly hoops to make GCC accept that a function may not always
be called.

llvm-svn: 107124
2010-06-29 06:46:00 +00:00
Dan Gohman
0824affeff Add an Intraprocedural form of BasicAliasAnalysis, which aims to
properly handles instructions and arguments defined in different
functions, or across recursive function iterations.

llvm-svn: 107109
2010-06-29 00:50:39 +00:00
Dan Gohman
7c34ece501 Fix Value::stripPointerCasts and BasicAA to avoid trouble on
code in unreachable blocks, which have have use-def cycles.
This fixes PR7514.

llvm-svn: 107071
2010-06-28 21:16:52 +00:00
Gabor Greif
1abbde3103 use ArgOperand accessors
llvm-svn: 106697
2010-06-23 23:38:07 +00:00
Eric Christopher
7258dcd77f Revert 101465, it broke internal OpenGL testing.
Probably the best way to know that all getOperand() calls have been handled
is to replace that API instead of updating.

llvm-svn: 101579
2010-04-16 23:37:20 +00:00
Gabor Greif
f375520f7b reapply r101434
with a fix for self-hosting

rotate CallInst operands, i.e. move callee to the back
of the operand array

the motivation for this patch are laid out in my mail to llvm-commits:
more efficient access to operands and callee, faster callgraph-construction,
smaller compiler binary

llvm-svn: 101465
2010-04-16 15:33:14 +00:00
Gabor Greif
403e9694f9 back out r101423 and r101397, they break llvm-gcc self-host on darwin10
llvm-svn: 101434
2010-04-16 01:16:20 +00:00
Gabor Greif
33ae80bff7 reapply r101364, which has been backed out in r101368
with a fix

rotate CallInst operands, i.e. move callee to the back
of the operand array

the motivation for this patch are laid out in my mail to llvm-commits:
more efficient access to operands and callee, faster callgraph-construction,
smaller compiler binary

llvm-svn: 101397
2010-04-15 20:51:13 +00:00
Gabor Greif
9fd00c7d25 back out r101364, as it trips the linux nightlybot on some clang C++ tests
llvm-svn: 101368
2010-04-15 12:46:56 +00:00
Gabor Greif
aafd209632 rotate CallInst operands, i.e. move callee to the back
of the operand array

the motivation for this patch are laid out in my mail to llvm-commits:
more efficient access to operands and callee, faster callgraph-construction,
smaller compiler binary

llvm-svn: 101364
2010-04-15 10:49:53 +00:00
Dan Gohman
cb45bd9cb3 Pointers to zero-sized objects don't point to overlapping objects.
llvm-svn: 100789
2010-04-08 18:11:50 +00:00
Duncan Sands
19d0b47b1f There are two ways of checking for a given type, for example isa<PointerType>(T)
and T->isPointerTy().  Convert most instances of the first form to the second form.
Requested by Chris.

llvm-svn: 96344
2010-02-16 11:11:14 +00:00
Chris Lattner
af362f014d add some new methods to adjust this pointers. Not used yet.
llvm-svn: 94013
2010-01-20 19:26:14 +00:00
Chris Lattner
29f82a1465 move DecomposeGEPExpression out into ValueTracking.cpp
llvm-svn: 89956
2009-11-26 17:12:50 +00:00
Chris Lattner
631c5b2cb9 teach GetLinearExpression to be a bit more aggressive.
llvm-svn: 89955
2009-11-26 17:00:01 +00:00
Chris Lattner
5c1cfc252c resolve a fixme. I haven't figured out how to write a testcase
to exercise this though.

llvm-svn: 89954
2009-11-26 16:52:32 +00:00
Chris Lattner
29bc8a91d3 Teach basicaa that x|c == x+c when the c bits of x are clear. This
allows us to compile the example in readme.txt into:

LBB1_1:                                                     ## %bb
	movl	4(%rdx,%rax), %ecx
	movl	%ecx, %esi
	imull	(%rdx,%rax), %esi
	imull	%esi, %ecx
	movl	%esi, 8(%rdx,%rax)
	imull	%ecx, %esi
	movl	%ecx, 12(%rdx,%rax)
	movl	%esi, 16(%rdx,%rax)
	imull	%ecx, %esi
	movl	%esi, 20(%rdx,%rax)
	addq	$16, %rax
	cmpq	$4000, %rax
	jne	LBB1_1

instead of:

LBB1_1: 
	movl	(%rdx,%rax), %ecx
	imull	4(%rdx,%rax), %ecx
	movl	%ecx, 8(%rdx,%rax)
	imull	4(%rdx,%rax), %ecx
	movl	%ecx, 12(%rdx,%rax)
	imull	8(%rdx,%rax), %ecx
	movl	%ecx, 16(%rdx,%rax)
	imull	12(%rdx,%rax), %ecx
	movl	%ecx, 20(%rdx,%rax)
	addq	$16, %rax
	cmpq	$4000, %rax
	jne	LBB1_1

GCC (4.2) doesn't seem to be able to eliminate the loads in this 
testcase either, it generates:

L2:
	movl	(%rdx), %eax
	imull	4(%rdx), %eax
	movl	%eax, 8(%rdx)
	imull	4(%rdx), %eax
	movl	%eax, 12(%rdx)
	imull	8(%rdx), %eax
	movl	%eax, 16(%rdx)
	imull	12(%rdx), %eax
	movl	%eax, 20(%rdx)
	addl	$4, %ecx
	addq	$16, %rdx
	cmpl	$1002, %ecx
	jne	L2

llvm-svn: 89952
2009-11-26 16:26:43 +00:00
Chris Lattner
12dacdd359 teach basicaa that A[i] != A[i+1].
llvm-svn: 89951
2009-11-26 16:18:10 +00:00
Chris Lattner
7a5b56aca9 Change the other half of aliasGEP (which handles GEP differencing) to use DecomposeGEPExpression. This dramatically simplifies and shrinks the code by eliminating the horrible CheckGEPInstructions method, fixes a miscompilation (@test3) and makes the code more aggressive. In particular, we now handle the @test4 case, which is reduced from the SmallPtrSet constructor. Missing this caused us to emit a variable length memset instead of a fixed size one.
llvm-svn: 89922
2009-11-26 02:17:34 +00:00
Chris Lattner
5341c9679d Generalize DecomposeGEPExpression to exactly handle what Value::getUnderlyingObject does (when TD is around). This allows us to avoid calling DecomposeGEPExpression unless the ultimate alias check we care about passes, speedup up BasicAA a bit.
llvm-svn: 89920
2009-11-26 02:14:59 +00:00
Chris Lattner
8928899413 Implement a new DecomposeGEPExpression method, which decomposes a GEP into a list of scaled offsets. Use this to eliminate some previous ad-hoc code which was subtly broken (it assumed all Constant*'s were non-zero, but strange constant express could be zero).
llvm-svn: 89915
2009-11-26 02:13:03 +00:00
Chris Lattner
a99edbedd1 Use GEPOperator more pervasively to simplify code.
llvm-svn: 89914
2009-11-26 02:11:08 +00:00
Chris Lattner
214ef9a4ef fix comment, thanks all :)
llvm-svn: 89666
2009-11-23 17:07:35 +00:00
Chris Lattner
1e7b37ebba use the new isNoAlias method to simplify some code, only do an escaping check if
we have a non-constant pointer.  Constant pointers can't be local.

llvm-svn: 89665
2009-11-23 16:46:41 +00:00
Chris Lattner
98e25326a0 whitespace cleanup, tidying
llvm-svn: 89664
2009-11-23 16:45:27 +00:00
Chris Lattner
84ed59abcf speed up BasicAA a bit by implementing a long-standing TODO.
llvm-svn: 89663
2009-11-23 16:44:43 +00:00
Chris Lattner
a13c9d1a5e add fixme for dubious code. Duncan, what do you think?
llvm-svn: 89602
2009-11-22 16:16:48 +00:00
Chris Lattner
db1e9f1290 remove a silly condition that doesn't make a lot of sense anymore.
llvm-svn: 89601
2009-11-22 16:15:59 +00:00
Chris Lattner
d6a49ad25a reduce indentation, no functionality change.
llvm-svn: 89600
2009-11-22 16:05:05 +00:00
Chris Lattner
88874ec60a Remove the AliasAnalysis::getMustAliases method, which is dead.
The hasNoModRefInfoForCalls isn't worth it as a filter because 
basicaa provides m/r info and everything chains to it, so remove
it.

llvm-svn: 89599
2009-11-22 16:01:44 +00:00
Dan Gohman
94e617627d Extend CaptureTracking to indicate when a value is never stored, even
if it is not ultimately captured. Teach BasicAliasAnalysis that a 
local object address which does not escape and is never stored does
not alias with a value resulting from a load.

llvm-svn: 89398
2009-11-19 21:57:48 +00:00
Nick Lewycky
c53e2ecf02 Teach BasicAA that a constant expression can't alias memory provably not
allocated until runtime (such as an alloca). Patch by Hans Wennborg!

llvm-svn: 88760
2009-11-14 06:15:14 +00:00
Dan Gohman
ccb4584edd Default-addressspace null pointers don't alias anything. This allows
GVN to be more aggressive. Patch by Hans Wennborg! (with a comment added by me)

llvm-svn: 86582
2009-11-09 19:29:11 +00:00
Chris Lattner
46b5c642b9 remove a bunch of extraneous LLVMContext arguments
from various APIs, addressing PR5325.

llvm-svn: 86231
2009-11-06 04:27:31 +00:00
Victor Hernandez
f390e04a47 Rename MallocFreeHelper as MemoryBuiltins
llvm-svn: 85286
2009-10-27 20:05:49 +00:00
Victor Hernandez
762195bd01 Rename MallocHelper as MallocFreeHelper, since it now also identifies calls to free()
llvm-svn: 85181
2009-10-26 23:58:56 +00:00
Dan Gohman
3b7ba5f35b Teach BasicAA how to analyze Select instructions, and make it more
aggressive on PHI instructions.

llvm-svn: 85158
2009-10-26 21:55:43 +00:00
Nick Lewycky
974e12b2d3 Remove includes of Support/Compiler.h that are no longer needed after the
VISIBILITY_HIDDEN removal.

llvm-svn: 85043
2009-10-25 06:57:41 +00:00
Nick Lewycky
02d5f77d26 Remove VISIBILITY_HIDDEN from class/struct found inside anonymous namespaces.
Chris claims we should never have visibility_hidden inside any .cpp file but
that's still not true even after this commit.

llvm-svn: 85042
2009-10-25 06:33:48 +00:00
Victor Hernandez
8acf2956b8 Remove AllocationInst. Since MallocInst went away, AllocaInst is the only subclass of AllocationInst, so it no longer is necessary.
llvm-svn: 84969
2009-10-23 21:09:37 +00:00
Chris Lattner
b2647b9e67 inline isGEP away.
llvm-svn: 84373
2009-10-17 23:48:54 +00:00
Evan Cheng
8ec25937f1 When checking aliases between phi sources and V2, we know the sources are not themselves phi nodes. However, V2 may be. Call aliasCheck with V2 first to potentially eliminate a std::swap call.
llvm-svn: 84226
2009-10-16 00:33:09 +00:00
Nick Lewycky
d708a4908c Add missing break statements! Thanks to Duncan Sands for pointing this out!
llvm-svn: 84191
2009-10-15 18:48:58 +00:00
Nick Lewycky
9cec2380f2 Teach basicaa about memcpy/memmove/memset. The length argument can be used to
improve alias results if constant, and the source pointer can't be modified.

llvm-svn: 84175
2009-10-15 07:11:24 +00:00
Nick Lewycky
d7216cf74c Teach BasicAA to use the size parameter of the memory use marker intrinsics.
llvm-svn: 84174
2009-10-15 06:12:11 +00:00
Nick Lewycky
fcb27ad54c Take advantage of TargetData when available; we know that the atomic intrinsics
only dereference the element they point to directly with no pointer arithmetic.

llvm-svn: 84159
2009-10-15 00:36:35 +00:00
Evan Cheng
b3ccb6498c Clear VisitedPHIs after use.
llvm-svn: 84080
2009-10-14 06:46:26 +00:00
Evan Cheng
c1eed9d120 Another BasicAA fix. If a value does not alias a GEP's base pointer, then it
cannot alias the GEP. GEP pointer alias rule states this clearly:
A pointer value formed from a getelementptr instruction is associated with the
addresses associated with the first operand of the getelementptr.

llvm-svn: 84079
2009-10-14 06:41:49 +00:00
Evan Cheng
f92f5557ee More code clean up based on patch feedback.
llvm-svn: 84074
2009-10-14 05:22:03 +00:00
Evan Cheng
31565b3e9f Change VisitedPHIs into an instance variable that's freed by each alias() call.
llvm-svn: 84072
2009-10-14 05:05:02 +00:00
Evan Cheng
c10e88db22 Teach basic AA about PHI nodes. If all operands of a phi NoAlias another value than it's safe to declare the PHI NoAlias the value. Ditto for MustAlias.
llvm-svn: 84038
2009-10-13 22:02:20 +00:00
Evan Cheng
f1f3dd3c3c Refactor some code. No functionality changes.
llvm-svn: 84000
2009-10-13 18:42:04 +00:00
Nick Lewycky
e2782c7614 Teach BasicAA a little something about the atomic intrinsics: they can only
modify through the pointer they're given.

llvm-svn: 83959
2009-10-13 07:48:38 +00:00
Victor Hernandez
537d8d99be Enhance analysis passes so that they apply the same analysis to malloc calls as to MallocInst.
Reviewed by Eli Friedman.

llvm-svn: 82281
2009-09-18 21:34:51 +00:00
Dan Gohman
bc1d841a63 Use stripPointerCasts instead of doing the same manually.
llvm-svn: 80267
2009-08-27 18:02:03 +00:00
Owen Anderson
55f1c09e31 Push LLVMContexts through the IntegerType APIs.
llvm-svn: 78948
2009-08-13 21:58:54 +00:00
Owen Anderson
5a1acd9912 Move a few more APIs back to 2.5 forms. The only remaining ones left to change back are
metadata related, which I'm waiting on to avoid conflicting with Devang.

llvm-svn: 77721
2009-07-31 20:28:14 +00:00
Owen Anderson
487375e9a2 Move ConstantExpr to 2.5 API.
llvm-svn: 77494
2009-07-29 18:55:55 +00:00
Dan Gohman
43d19d61d4 Make AliasAnalysis and related classes use
getAnalysisIfAvailable<TargetData>().

llvm-svn: 77028
2009-07-25 00:48:42 +00:00
Owen Anderson
edb4a70325 Revert the ConstantInt constructors back to their 2.5 forms where possible, thanks to contexts-on-types. More to come.
llvm-svn: 77011
2009-07-24 23:12:02 +00:00
Owen Anderson
47db941fd3 Get rid of the Pass+Context magic.
llvm-svn: 76702
2009-07-22 00:24:57 +00:00
Dan Gohman
33a3fd0b9c Revert the addition of hasNoPointerOverflow to GEPOperator.
Getelementptrs that are defined to wrap are virtually useless to
optimization, and getelementptrs that are undefined on any kind
of overflow are too restrictive -- it's difficult to ensure that
all intermediate addresses are within bounds. I'm going to take
a different approach.

Remove a few optimizations that depended on this flag.

llvm-svn: 76437
2009-07-20 17:43:30 +00:00
Dan Gohman
1d548d851a Make BasicAliasAnalysis and Value::getUnderlyingObject use
GEPOperator's hasNoPointer0verflow(), and make a few places in instcombine
that create GEPs that may overflow clear the NoOverflow value. Among
other things, this partially addresses PR2831.

llvm-svn: 76252
2009-07-17 22:25:10 +00:00
Owen Anderson
20b34ac794 Move the ConstantInt uniquing table into LLVMContextImpl. This exposed a number of issues in
our current context-passing stuff, which is also fixed here

llvm-svn: 76089
2009-07-16 18:04:31 +00:00
Torok Edwin
fbcc663cbf llvm_unreachable->llvm_unreachable(0), LLVM_UNREACHABLE->llvm_unreachable.
This adds location info for all llvm_unreachable calls (which is a macro now) in
!NDEBUG builds.
In NDEBUG builds location info and the message is off (it only prints
"UREACHABLE executed").

llvm-svn: 75640
2009-07-14 16:55:14 +00:00
Torok Edwin
56d0659726 assert(0) -> LLVM_UNREACHABLE.
Make llvm_unreachable take an optional string, thus moving the cerr<< out of
line.
LLVM_UNREACHABLE is now a simple wrapper that makes the message go away for
NDEBUG builds.

llvm-svn: 75379
2009-07-11 20:10:48 +00:00
Owen Anderson
38264b1554 "LLVMContext* " --> "LLVMContext *"
llvm-svn: 74878
2009-07-06 23:00:19 +00:00
Owen Anderson
39f00cc1d4 Thread LLVMContext through the constant folding APIs, which touches a lot of files.
llvm-svn: 74844
2009-07-06 18:42:36 +00:00
Owen Anderson
e9454e8c25 Remove unneeded #include.
llvm-svn: 73911
2009-06-22 22:09:07 +00:00
Dan Gohman
776e4c8d35 Teach BasicAliasAnalysis to understand constant gep indices that fall
beyond their associated static array type.

I believe that this fixes a legitimate bug, because BasicAliasAnalysis
already has code to check for this condition that works for non-constant
indices, however it was missing the case of constant indices. With this
change, it checks for both.

This fixes PR4267, and miscompiles of SPEC 188.ammp and 464.h264.href.

llvm-svn: 72451
2009-05-27 01:48:27 +00:00
Duncan Sands
af9eaa830a Rename PaddedSize to AllocSize, in the hope that this
will make it more obvious what it represents, and stop
it being confused with the StoreSize.

llvm-svn: 71349
2009-05-09 07:06:46 +00:00
Duncan Sands
73247d2edc Generalize some alias analysis logic from atomic
intrinsics to any IntrWriteArgMem intrinsics.

llvm-svn: 64551
2009-02-14 10:56:35 +00:00
Nick Lewycky
c60bd012bc BasicAA was making the assumption that a local allocation which hadn't escaped
couldn't ever be the return of call instruction. However, it's quite possible
that said local allocation is itself the return of a function call. That's
what malloc and calloc are for, actually.

llvm-svn: 64442
2009-02-13 07:06:27 +00:00
Owen Anderson
98a3617fba Refactor my previous change to maintain the distinction between AliasAnalysis and BasicAliasAnalysis. This involves some wider changes because it
folds away some never-used methods.

llvm-svn: 63900
2009-02-05 23:36:27 +00:00
Owen Anderson
1caf7fef8e Finish making AliasAnalysis aware of the fact that most atomic intrinsics only dereference their arguments, and enhance
BasicAA to make use of this fact when computing ModRef info.

llvm-svn: 63718
2009-02-04 05:16:46 +00:00
Dan Gohman
fb306c0a10 Move isIdentifiedObject and isNoAliasCall into AliasAnalysis.cpp since
they are useful to analyses other than BasicAliasAnalysis.cpp. Include
the full comment for isIdentifiedObject in the header file. Thanks to
Chris for suggeseting this.

llvm-svn: 63589
2009-02-03 01:28:32 +00:00
Dan Gohman
1ee0d41ef8 Fix a post-RA scheduling dependency bug.
If a MachineInstr doesn't have a memoperand but has an opcode that
is known to load or store, assume its memory reference may alias
*anything*, including stack slots which the compiler completely
controls.

To partially compensate for this, teach the ScheduleDAG building
code to do basic getUnderlyingValue analysis. This greatly
reduces the number of instructions that require restrictive
dependencies. This code will need to be revisited when we start
doing real alias analysis, but it should suffice for now.

llvm-svn: 63370
2009-01-30 02:49:14 +00:00
Duncan Sands
e0aa0d677d BasicAliasAnalysis and FunctionAttrs were both
doing very similar pointer capture analysis.
Factor out the common logic.  The new version
is from FunctionAttrs since it does a better
job than the version in BasicAliasAnalysis

llvm-svn: 62461
2009-01-18 12:19:30 +00:00
Gabor Greif
1b94d420ae add a comment
llvm-svn: 62436
2009-01-18 00:27:21 +00:00
Duncan Sands
dc020f9c3c Rename getABITypeSize to getTypePaddedSize, as
suggested by Chris.

llvm-svn: 62099
2009-01-12 20:38:59 +00:00
Chris Lattner
2089cd09ba make tblgen autogenerate the nocapture intrinsics for
llvm.memcpy/memset/memmove.  This allows removal of some 
hackish code from basicaa.

llvm-svn: 62071
2009-01-12 02:41:37 +00:00
Duncan Sands
8d65f3690e When checking if an Argument escapes, check if
the argument is marked nocapture - no need to
analyze the argument if the answer is already
known!

llvm-svn: 61753
2009-01-05 21:19:53 +00:00
Nick Lewycky
2abb108f1b Resubmit support for the 'nocapture' attribute.
The problematic part of this patch is that we were out of attribute bits,
requiring some fancy bit hacking to make it fit (by shrinking alignment)
without breaking existing users or the file format.

This change will require users to rebuild llvm-gcc to match llvm.

llvm-svn: 61239
2008-12-19 06:39:12 +00:00
Bill Wendling
a397baea88 Temporarily revert r61019, r61030, and r61040. These were breaking LLVM Release
builds.

llvm-svn: 61094
2008-12-16 19:06:48 +00:00
Chris Lattner
e3401db1f3 Teach basicaa to use the nocapture attribute when possible. When the
intrinsics are properly marked nocapture, the fixme should be addressed.

llvm-svn: 61040
2008-12-15 18:59:22 +00:00
Chris Lattner
2e84a548d6 Allow basicaa to walk through geps with identical indices in
parallel, allowing it to decide that P/Q must alias if A/B
must alias in things like:
 P = gep A, 0, i, 1
 Q = gep B, 0, i, 1

This allows GVN to delete 62 more instructions out of 403.gcc.

llvm-svn: 60820
2008-12-10 01:04:47 +00:00
Chris Lattner
702e46ed54 Teach BasicAA::getModRefInfo(CallSite, CallSite) some
tricks based on readnone/readonly functions.

Teach memdep to look past readonly calls when analyzing
deps for a readonly call.  This allows elimination of a
few more calls from 403.gcc:

before:
     63 gvn    - Number of instructions PRE'd
 153986 gvn    - Number of instructions deleted
  50069 gvn    - Number of loads deleted

after:
     63 gvn    - Number of instructions PRE'd
 153991 gvn    - Number of instructions deleted
  50069 gvn    - Number of loads deleted

5 calls isn't much, but this adds plumbing for the next change.

llvm-svn: 60794
2008-12-09 21:19:42 +00:00
Duncan Sands
714ffa36d3 Fix comment typo.
llvm-svn: 60697
2008-12-08 14:01:59 +00:00
Chris Lattner
2f9d8458c8 Some minor optimizations for isObjectSmallerThan.
llvm-svn: 60687
2008-12-08 06:28:54 +00:00
Nick Lewycky
d59572cb22 Seriously strengthen the guarantee offered by noalias on a function's return
value. It must now be as if the pointer were allocated and has not escaped to
the caller. Thanks to Dan Gohman for pointing out the error in the original
and helping devise this definition.

llvm-svn: 59940
2008-11-24 05:00:44 +00:00
Nick Lewycky
f5ffcbcd0b Extend the 'noalias' attribute to function return values. This is intended to
indicate functions that allocate, such as operator new, or list::insert. The
actual definition is slightly less strict (for now).

No changes to the bitcode reader/writer, asm printer or verifier were needed.

llvm-svn: 59934
2008-11-24 03:41:24 +00:00
Duncan Sands
d65a4daeea Factorize code: remove variants of "strip off
pointer bitcasts and GEP's", and centralize the
logic in Value::getUnderlyingObject.  The
difference with stripPointerCasts is that
stripPointerCasts only strips GEPs if all
indices are zero, while getUnderlyingObject
strips GEPs no matter what the indices are.

llvm-svn: 56922
2008-10-01 15:25:41 +00:00
Devang Patel
ba3fa6c6e1 s/ParameterAttributes/Attributes/g
llvm-svn: 56513
2008-09-23 23:03:40 +00:00
Dan Gohman
a79db30d28 Tidy up several unbeseeming casts from pointer to intptr_t.
llvm-svn: 55779
2008-09-04 17:05:41 +00:00
Chris Lattner
fb46605e47 simplify some code by using a helper function. This really really
wants a 'nocapture' predicate.

llvm-svn: 52304
2008-06-16 06:38:26 +00:00
Chris Lattner
2d33297d00 move a bunch of predicates up into their own section
in this file, no other changes.

llvm-svn: 52303
2008-06-16 06:30:22 +00:00
Chris Lattner
fa48258a61 Other parts of this code treat noalias arguments as objects for
the purposes of escape analysis.

llvm-svn: 52302
2008-06-16 06:28:01 +00:00
Chris Lattner
b35d9b5e07 If we are checking to see if the result of a call aliases a
pointer derived from a local allocation, if the local allocation
never escapes, the pointers can't alias.  This implements PR2436

llvm-svn: 52301
2008-06-16 06:19:11 +00:00
Chris Lattner
98ad816f58 Refactor basicaa's main alias function somethin' fierce.
This fixes several minor bugs (such as returning noalias
for comparisons between external weak functions an null) but
is mostly a cleanup.

llvm-svn: 52299
2008-06-16 06:10:11 +00:00
Wojciech Matyjewicz
416867a81b Fixes PR2395. Looking for a constant in a GEP tail (when the first GEP
is longer than the second one) should stop after finding one. Added break 
instruction guarantees it. It also changes difference between offsets to 
absolute value of this difference in the condition.

llvm-svn: 51875
2008-06-02 17:26:12 +00:00