Commit Graph

4199 Commits

Author SHA1 Message Date
Chris Lattner
84f83c2727 enhance jump threading to preserve TBAA information when PRE'ing loads,
fixing rdar://11039258, an issue that came up when inspecting clang's 
bootstrapped codegen.

llvm-svn: 152635
2012-03-13 18:07:41 +00:00
Duncan Sands
60c339c405 Generalize the "trunc(ptrtoint(x)) - trunc(ptrtoint(y)) ->
trunc(ptrtoint(x-y))" optimization introduced by Chandler.

llvm-svn: 152626
2012-03-13 14:07:05 +00:00
Duncan Sands
9931da5d8d Uniformize the InstructionSimplify interface by ensuring that all routines
take a TargetLibraryInfo parameter.  Internally, rather than passing TD, TLI
and DT parameters around all over the place, introduce a struct for holding
them.

llvm-svn: 152623
2012-03-13 11:42:19 +00:00
Eli Friedman
77682009bc Fix regression from r151466: an we can't replace uses of an instruction reachable from the entry block with uses of an instruction not reachable from the entry block. PR12231.
llvm-svn: 152595
2012-03-13 01:06:07 +00:00
Chandler Carruth
ce889fff68 Address some review comments from Duncan. This moves the iterative
offset accumulation to use a boring APInt instead of ConstantExprs.
I didn't go all the way to an 'int64_t' because I wanted APInt to handle
any magic required to properly wrap the arithmetic when the pointer
width is <64 bits. If there is a significant penalty from using APInt
here, first off WTF, and secondly let me know and I'll do the math by
hand.

I've left one layer still operating w/ ConstantExpr because it makes the
interface quite a bit simpler, and that one isn't iterative so has much
lower cost.

I suppose this may potentially speed up some strang compilation
situations, but I don't really expect much. It should have no functional
impact either way.

llvm-svn: 152590
2012-03-13 00:06:15 +00:00
Chandler Carruth
d1c1c98162 Teach instsimplify how to constant fold pointer differences.
Typically instcombine has handled this, but pointer differences show up
in several contexts where we would like to get constant folding, and
cannot afford to run instcombine. Specifically, I'm working on improving
the constant folding of arguments used in inline cost analysis with
instsimplify.

Doing this in instsimplify implies some algorithm changes. We have to
handle multiple layers of all-constant GEPs because instsimplify cannot
fold them into a single GEP the way instcombine can. Also, we're only
interested in all-constant GEPs. The result is that this doesn't really
replace the instcombine logic, it's just complimentary and focused on
constant folding.

Reviewed on IRC by Benjamin Kramer.

llvm-svn: 152555
2012-03-12 11:19:31 +00:00
Stepan Dyatkovskiy
72fdcabd4d llvm::SwitchInst
Renamed methods caseBegin, caseEnd and caseDefault with case_begin, case_end, and case_default.
Added some notes relative to case iterators.

llvm-svn: 152532
2012-03-11 06:09:17 +00:00
Benjamin Kramer
e68be7638b Make helper static, so it can be inlined into its sole caller.
llvm-svn: 152515
2012-03-10 22:41:06 +00:00
Bill Wendling
59ed3a53a6 As Duncan pointed out, pointers tend not to be in floating point format...for now.
llvm-svn: 152499
2012-03-10 18:20:55 +00:00
Bill Wendling
5f16e35eed Make this transformation slightly less agressive and more correct.
The 'CmpInst::isFalseWhenEqual' function returns 'false' for values other than
simply equality. For instance, it returns 'false' for <= or >=. This isn't the
correct behavior for this transformation, which is checking for strict equality
and non-equality. It was causing the gcc.c-torture/execute/frame-address.c test
to fail because it would completely (and incorrectly) optimize a whole function
into a 'ret i32 0'.

llvm-svn: 152497
2012-03-10 17:56:03 +00:00
Chandler Carruth
a4cd27625a Refactor some methods to look through bitcasts and GEPs on pointers into
a common collection of methods on Value, and share their implementation.
We had two variations in two different places already, and I need the
third variation for inline cost estimation.

Reviewed by Duncan Sands on IRC, but further comments here welcome.

llvm-svn: 152490
2012-03-10 08:39:09 +00:00
Nick Lewycky
a2fe9e0d87 Factor out the analysis of addition and subtraction in ComputeMaskedBits. Reuse
it to analyze extractvalue(llvm.[us](add|sub).with.overflow.*) intrinsics!

llvm-svn: 152398
2012-03-09 09:23:50 +00:00
Chandler Carruth
63f95ab839 Undo a previous restriction on the inline cost calculation which Nick
introduced. Specifically, there are cost reductions for all
constant-operand icmp instructions against an alloca, regardless of
whether the alloca will in fact be elligible for SROA. That means we
don't want to abort the icmp reduction computation when we abort the
SROA reduction computation. That in turn frees us from the need to keep
a separate worklist and defer the ICmp calculations.

Use this new-found freedom and some judicious function boundaries to
factor the innards of computing the cost factor of any given instruction
out of the loop over the instructions and into static helper functions.
This greatly simplifies the code, and hopefully makes it more clear what
is happening here.

Reviewed by Eric Christopher. There is some concern that we'd like to
ensure this doesn't get out of hand, and I plan to benchmark the effects
of this change over the next few days along with some further fixes to
the inline cost.

llvm-svn: 152368
2012-03-09 02:49:36 +00:00
Stepan Dyatkovskiy
79f3dd93b7 Taken into account Duncan's comments for r149481 dated by 2nd Feb 2012:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/136146.html

Implemented CaseIterator and it solves almost all described issues: we don't need to mix operand/case/successor indexing anymore. Base iterator class is implemented as a template since it may be initialized either from "const SwitchInst*" or from "SwitchInst*".

ConstCaseIt is just a read-only iterator.
CaseIt is read-write iterator; it allows to change case successor and case value.

Usage of iterator allows totally remove resolveXXXX methods. All indexing convertions done automatically inside the iterator's getters.

Main way of iterator usage looks like this:
SwitchInst *SI = ... // intialize it somehow

for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); i != e; ++i) {
  BasicBlock *BB = i.getCaseSuccessor();
  ConstantInt *V = i.getCaseValue();
  // Do something.
}

If you want to convert case number to TerminatorInst successor index, just use getSuccessorIndex iterator's method.
If you want initialize iterator from TerminatorInst successor index, use CaseIt::fromSuccessorIndex(...) method.

There are also related changes in llvm-clients: klee and clang.

llvm-svn: 152297
2012-03-08 07:06:20 +00:00
Chandler Carruth
c0ed0a5f22 Rotate two of the functions used to count bonuses for the inline cost
analysis to be methods on the cost analysis's function info object
instead of the code metrics object. These really are just users of the
code metrics, they're building the information for the function's
analysis.

This is the first step of growing the amount of information we collect
about a function in order to cope with pair-wise simplifications due to
allocas.

llvm-svn: 152283
2012-03-08 02:04:19 +00:00
Nick Lewycky
7c4db49d7e No functionality change. Type::isSized() can be expensive, so avoid calling it
until after other inexpensive tests.

llvm-svn: 152195
2012-03-07 02:27:53 +00:00
Eli Friedman
eec5df7382 A few more cases of missing masking in ComputeMaskedBits; found by inspection.
llvm-svn: 152070
2012-03-05 23:22:40 +00:00
Eli Friedman
59cebb7902 Make sure we don't return bits outside the mask in ComputeMaskedBits. PR12189.
llvm-svn: 152066
2012-03-05 23:09:40 +00:00
Benjamin Kramer
2a3719125f LVI: Recognize the form instcombine canonicalizes range checks into when forming constant ranges.
This could probably be made a lot smarter, but this is a common case and doesn't require LVI to scan a lot
of code. With this change CVP can optimize away the "shift == 0" case in Hashing.h that only gets hit when
"shift" is in a range not containing 0.

llvm-svn: 151919
2012-03-02 15:34:43 +00:00
Eli Friedman
1ff1d1f1bc Duncan pointed out that if the alignment isn't explicitly specified, it defaults to the ABI alignment. Given that, make this code a bit more aggressive in such cases.
llvm-svn: 151584
2012-02-27 23:16:46 +00:00
Eli Friedman
15f56db6c0 Teach BasicAA about the LLVM IR rules that allow reading past the end of an object given sufficient alignment. Fixes PR12098.
llvm-svn: 151553
2012-02-27 20:46:07 +00:00
Rafael Espindola
2d9b864afe Fix this assert. IP can point to an instruction with strange dominance
properties (invoke). Just assert that the instruction we return dominates
the insertion point.

llvm-svn: 151511
2012-02-27 02:13:03 +00:00
Rafael Espindola
c333947449 Don't call dominates on unreachable instructions. Should fix the dragonegg
build. Testcase is still reducing.

llvm-svn: 151474
2012-02-26 05:30:08 +00:00
Rafael Espindola
137548bb3e And update the comment...
llvm-svn: 151472
2012-02-26 02:36:56 +00:00
Rafael Espindola
e63adef174 Enable the assert that got all this dominator work started.
llvm-svn: 151471
2012-02-26 02:29:18 +00:00
Rafael Espindola
34b7c064cb Change the implementation of dominates(inst, inst) to one based on what the
verifier does. This correctly handles invoke.
Thanks to Duncan, Andrew and Chris for the comments.
Thanks to Joerg for the early testing.

llvm-svn: 151469
2012-02-26 02:19:19 +00:00
Nick Lewycky
a93c874757 Reinstate the optimization from r151449 with a fix to not turn 'gep %x' into
'gep null' when the icmp predicate is unsigned (or is signed without inbounds).

llvm-svn: 151467
2012-02-26 02:09:49 +00:00
Rafael Espindola
d9e654ca63 Don't call dominates on unreachable instructions.
llvm-svn: 151466
2012-02-26 01:50:14 +00:00
Nick Lewycky
849715d31f Roll these back to r151448 until I figure out how they're breaking
MultiSource/Applications/lua.

llvm-svn: 151463
2012-02-25 23:01:19 +00:00
Nick Lewycky
1636c6eaef An argument and a local identified object (eg. a noalias call) could turn out
equal if both are null. In the test, scope type %t and global @y by adding a
'gep' prefix to them.

llvm-svn: 151452
2012-02-25 20:19:07 +00:00
Nick Lewycky
808d0e3fa7 Fix five-letter typo in comment.
llvm-svn: 151450
2012-02-25 19:12:58 +00:00
Nick Lewycky
94be1c7d95 Teach instsimplify to be more aggressive when analyzing comparisons of pointers
by using llvm::isIdentifiedObject. Also teach it to handle GEPs that have
the same base pointer and constant operands. Fixes PR11238!

llvm-svn: 151449
2012-02-25 19:07:42 +00:00
Nick Lewycky
dce2cfc335 Move isKnownNonNull from private implementation detail of BasicAA to a public
function that others can use, next to llvm::isIdentifiedObject.

llvm-svn: 151446
2012-02-25 10:56:28 +00:00
Chris Lattner
b01936f21a fix PR12075, a regression in a recent transform I added. In unreachable code, gep chains can be infinite. Just like "stripPointerCasts", use a set to keep track of visited instructions so we don't recurse infinitely.
llvm-svn: 151383
2012-02-24 19:01:58 +00:00
Rafael Espindola
c378c75761 Fix typo.
llvm-svn: 151238
2012-02-23 05:38:51 +00:00
Chad Rosier
3703a1917a Remove extra semi-colons.
llvm-svn: 151169
2012-02-22 17:25:00 +00:00
Rafael Espindola
4f3e648dd0 Improve comment. Thanks for Andrew for the suggestion.
llvm-svn: 151127
2012-02-22 03:44:46 +00:00
Rafael Espindola
23cd372dbf Semantically revert 151015. Add a comment on why we should be able to assert
the dominance once the dominates method is fixed and why we can use the builder's
insertion point.
Fixes pr12048.

llvm-svn: 151125
2012-02-22 03:21:39 +00:00
Rafael Espindola
8d727cc0cb s/the the/the/
llvm-svn: 151079
2012-02-21 19:27:16 +00:00
Rafael Espindola
8ef9503d71 Use more idiomatic assert.
llvm-svn: 151026
2012-02-21 03:51:14 +00:00
Rafael Espindola
aec58a4177 Avoid warning on non assert builds.
llvm-svn: 151025
2012-02-21 03:48:30 +00:00
Rafael Espindola
232a730f45 It turns out that with the current scev organization ReuseOrCreateCast cannot
know where users will be added. Because of this, it cannot use
Builder.GetInsertPoint at all.

This patch
* removes the FIXME about adding the assert.
* adds a comment explaining hy we don't have one.
* removes a broken logic that only works for some callers and is not needed
  since r150884.
* adds an assert to caller that would have caught the bug fixed by r150884.

llvm-svn: 151015
2012-02-21 01:19:51 +00:00
Eric Christopher
742c530fa0 Make this a bit prettier and more obvious when a derived type isn't
derived from anything.

llvm-svn: 150975
2012-02-20 18:04:39 +00:00
Eric Christopher
69a0eb9258 If a derived type is also a composite type, print that information
too.

llvm-svn: 150974
2012-02-20 18:04:35 +00:00
Eric Christopher
ed41b1f1ef Add support for runtime languages on our forward declarations.
llvm-svn: 150973
2012-02-20 18:04:14 +00:00
Chris Lattner
50ad7c3f54 fold comparisons of gep'd alloca points with null to false,
implementing PR12013.  We now compile the testcase to:

__Z4testv:                              ## @_Z4testv
## BB#0:                                ## %_ZN4llvm15SmallVectorImplIiE9push_backERKi.exit
	pushq	%rbx
	subq	$64, %rsp
	leaq	32(%rsp), %rbx
	movq	%rbx, (%rsp)
	leaq	64(%rsp), %rax
	movq	%rax, 16(%rsp)
	movl	$1, 32(%rsp)
	leaq	36(%rsp), %rax
	movq	%rax, 8(%rsp)
	leaq	(%rsp), %rdi
	callq	__Z1gRN4llvm11SmallVectorIiLj8EEE
	movq	(%rsp), %rdi
	cmpq	%rbx, %rdi
	je	LBB0_2
## BB#1:
	callq	_free
LBB0_2:                                 ## %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit
	addq	$64, %rsp
	popq	%rbx
	ret

instead of:

__Z4testv:                              ## @_Z4testv
## BB#0:
	pushq	%rbx
	subq	$64, %rsp
	xorl	%eax, %eax
	leaq	(%rsp), %rbx
	addq	$32, %rbx
	movq	%rbx, (%rsp)
	movq	%rbx, 8(%rsp)
	leaq	64(%rsp), %rcx
	movq	%rcx, 16(%rsp)
	je	LBB0_2
## BB#1:
	movl	$1, 32(%rsp)
	movq	%rbx, %rax
LBB0_2:                                 ## %_ZN4llvm15SmallVectorImplIiE9push_backERKi.exit
	addq	$4, %rax
	movq	%rax, 8(%rsp)
	leaq	(%rsp), %rdi
	callq	__Z1gRN4llvm11SmallVectorIiLj8EEE
	movq	(%rsp), %rdi
	cmpq	%rbx, %rdi
	je	LBB0_4
## BB#3:
	callq	_free
LBB0_4:                                 ## %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit
	addq	$64, %rsp
	popq	%rbx
	ret

This doesn't shrink clang noticably though.

llvm-svn: 150944
2012-02-20 00:42:49 +00:00
Rafael Espindola
64fe8ada6e Temporarily disable this assert. Looks like it found a similar issue when
building bullet.

llvm-svn: 150885
2012-02-18 17:51:43 +00:00
Rafael Espindola
5154b9bedb Don't skip debug instructions when looking for the insertion point of
the cast. If we do, we can end up with

   inst1
   ---------------  < Insertion point
   dbg inst
   new inst

instead of the desired

   inst1
   new inst
   ---------------  < Insertion point
   dbg inst

Another option would be for InsertNoopCastOfTo (or its callers) to move the
insertion point and we would end up with

   inst1
   dbg inst
   new inst
   ---------------  < Insertion point

but that complicates the callers. This fixes PR12018 (and firefox's build).

llvm-svn: 150884
2012-02-18 17:22:58 +00:00
Eli Friedman
be89455c98 Fix a rather nasty regression from r150690: LHS != RHS does not imply LHS->stripPointerCasts() != RHS->stripPointerCasts().
llvm-svn: 150863
2012-02-18 03:29:25 +00:00
Dan Gohman
eb02ab2f74 Remove a comment about an alternative approach that wouldn't
actually work, at least as described. LLVM Metadata is not
intended to suppress LLVM IR rules, as it can be stripped at
any time.

llvm-svn: 150821
2012-02-17 18:33:38 +00:00