Commit Graph

181 Commits

Author SHA1 Message Date
Duncan Sands
d869b3847f Generalize some alias analysis logic from atomic
intrinsics to any IntrWriteArgMem intrinsics.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64551 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-14 10:56:35 +00:00
Nick Lewycky
826f7cebfd 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64442 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-13 07:06:27 +00:00
Owen Anderson
e79422096e 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63900 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-05 23:36:27 +00:00
Owen Anderson
fe9388ccb4 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63718 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-04 05:16:46 +00:00
Dan Gohman
a5f81bba4a 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63589 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-03 01:28:32 +00:00
Dan Gohman
3311a1f8f0 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63370 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-30 02:49:14 +00:00
Duncan Sands
8556d2a7f1 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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62461 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-18 12:19:30 +00:00
Gabor Greif
7f85bb6f83 add a comment
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62436 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-18 00:27:21 +00:00
Duncan Sands
ceb4d1aecb Rename getABITypeSize to getTypePaddedSize, as
suggested by Chris.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62099 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-12 20:38:59 +00:00
Chris Lattner
d4a2700fdc make tblgen autogenerate the nocapture intrinsics for
llvm.memcpy/memset/memmove.  This allows removal of some 
hackish code from basicaa.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62071 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-12 02:41:37 +00:00
Duncan Sands
91c9c31033 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!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61753 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-05 21:19:53 +00:00
Nick Lewycky
f23d0d392a 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61239 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-19 06:39:12 +00:00
Bill Wendling
6fa311c233 Temporarily revert r61019, r61030, and r61040. These were breaking LLVM Release
builds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61094 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-16 19:06:48 +00:00
Chris Lattner
1314f20283 Teach basicaa to use the nocapture attribute when possible. When the
intrinsics are properly marked nocapture, the fixme should be addressed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61040 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-15 18:59:22 +00:00
Chris Lattner
b957bda0bc 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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60820 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-10 01:04:47 +00:00
Chris Lattner
20d6f0982a 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60794 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-09 21:19:42 +00:00
Duncan Sands
1832705b06 Fix comment typo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60697 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-08 14:01:59 +00:00
Chris Lattner
295d4e953a Some minor optimizations for isObjectSmallerThan.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60687 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-08 06:28:54 +00:00
Nick Lewycky
b2b32fd3fe 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59940 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-24 05:00:44 +00:00
Nick Lewycky
02ff308aa1 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59934 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-24 03:41:24 +00:00
Duncan Sands
5d0392c6b3 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56922 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-01 15:25:41 +00:00
Devang Patel
eaf42abab6 s/ParameterAttributes/Attributes/g
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56513 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-23 23:03:40 +00:00
Dan Gohman
ae73dc1448 Tidy up several unbeseeming casts from pointer to intptr_t.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55779 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-04 17:05:41 +00:00
Chris Lattner
25df20f169 simplify some code by using a helper function. This really really
wants a 'nocapture' predicate.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52304 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-16 06:38:26 +00:00
Chris Lattner
defa1c8034 move a bunch of predicates up into their own section
in this file, no other changes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52303 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-16 06:30:22 +00:00
Chris Lattner
e7275794d3 Other parts of this code treat noalias arguments as objects for
the purposes of escape analysis.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52302 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-16 06:28:01 +00:00
Chris Lattner
845f0d2f0f 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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52301 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-16 06:19:11 +00:00
Chris Lattner
a413960a48 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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52299 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-16 06:10:11 +00:00
Wojciech Matyjewicz
98e3a6829a 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51875 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-02 17:26:12 +00:00
Dan Gohman
844731a7f1 Clean up the use of static and anonymous namespaces. This turned up
several things that were neither in an anonymous namespace nor static
but not intended to be global.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51017 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-13 00:00:25 +00:00
Duncan Sands
e47d98200e Fix a "large integer implicitly truncated to unsigned type"
warning.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50033 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-21 07:35:28 +00:00
Dale Johannesen
21d31a8d94 Don't assume a tail call can't reference a byval
argument to the outer function, this isn't correct.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49731 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-15 17:41:34 +00:00
Devang Patel
4f4c28f75f Restore isCFGOnly property of various analysis passes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48579 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-20 02:25:21 +00:00
Devang Patel
c758209153 PassInfo keep tracks whether a pass is an analysis pass or not.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48554 91177308-0d34-0410-b5e6-96231b3b80d8
2008-03-19 21:56:59 +00:00
Duncan Sands
ec5ec88d15 Fix a compiler warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47328 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-19 09:28:48 +00:00
Owen Anderson
851bfff50f In addition to arguments passed to it, memcpy (and all other calls) can ModRef pointers that alias their arguments as well. This fixes PR2057.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47317 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-19 06:47:18 +00:00
Chris Lattner
bb494bcb0e don't bother calling getUnderlyingObject for non-pointers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47272 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-18 17:28:21 +00:00
Owen Anderson
ef562471ce Since we're not checking for the more general AllocationInst first, we need to explicitly check
that Object is an Argument before casting it to one.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47268 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-18 10:11:00 +00:00
Owen Anderson
26d914ada3 This check is not correct for mallocs, so exclude them earlier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47263 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-18 09:11:02 +00:00
Owen Anderson
ae708a3d91 Fix a comment, and a bug where we weren't applying the tail call logic in cases that failed the first test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47253 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-18 03:52:21 +00:00
Owen Anderson
9aa7c35cee Fix bugs that Chris noticed in my last patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47252 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-18 02:31:23 +00:00
Chris Lattner
0ab5a4ae55 bitcasts of pointers are always pointers.
If we see a memcpy of a pointer, make sure to check later
uses of the pointer as well.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47250 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-18 02:11:28 +00:00
Owen Anderson
9b636cb338 Teach getModRefInfo that memcpy, memmove, and memset don't "capture" memory addresses.
Also, noalias arguments are be considered "like" stack allocated ones for this purpose, because
the only way they can be modref'ed is if they escape somewhere in the current function.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47247 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-17 21:29:08 +00:00
Chris Lattner
d087480166 getUnderlyingObject can return null, handle this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46318 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-24 19:07:10 +00:00
Chris Lattner
fd68750038 Teach basicaa that 'byval' arguments define a new memory location that
can't be aliased to other known objects.  This allows us to know that byval 
pointer args don't alias globals, etc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46315 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-24 18:00:32 +00:00
Chris Lattner
4ee451de36 Remove attribution from file headers, per discussion on llvmdev.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45418 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-29 20:36:04 +00:00
Wojciech Matyjewicz
4ba8cfc5a4 Make these loops follow GetGEPOperands() behavior.
Let: %q = GEP %p, X, ...
If %p is a GEP, we can chase baseptr further, only if X==0.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44999 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-13 16:22:58 +00:00
Chris Lattner
f88380ba2c Fix PR1782, patch by Wojtek Matyjewicz!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44733 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-09 07:35:13 +00:00
Duncan Sands
a3355ffb3d Rather than having special rules like "intrinsics cannot
throw exceptions", just mark intrinsics with the nounwind
attribute.  Likewise, mark intrinsics as readnone/readonly
and get rid of special aliasing logic (which didn't use
anything more than this anyway).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44544 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-03 20:06:50 +00:00
Duncan Sands
dff6710717 Integrate the readonly/readnone logic more deeply
into alias analysis.  This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter.  These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function.  Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite.  To reduce the
chance of misuse it is now protected.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44487 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-01 07:51:45 +00:00