Commit Graph

320 Commits

Author SHA1 Message Date
Dan Gohman
9a80b459ed Fix ScalarEvolution::getAddRecExpr's code which canonicalized the
nesting order of nested AddRec expressions to skip the transformation
if it would introduce an AddRec with operands not loop-invariant
with respect to its loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74343 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-26 22:36:20 +00:00
Dan Gohman
e890eead22 Fix SCEVAddRecExpr::isLoopInvariant to test if all of its operands
are loop invariant, not just the start operand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74338 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-26 22:17:21 +00:00
Dan Gohman
9311ef6a91 Minor whitespace cleanups.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74074 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 14:49:00 +00:00
Dan Gohman
e5aceed168 Simplify [su]max(MAX, n) to MAX. This comes up in loop tripcount
computations in loops with multiple exits.

Adjust the testcase for PR4436 so that the relevant portion isn't
optimized away.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74073 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 14:46:22 +00:00
Dan Gohman
64a845e836 Delete some orphaned comments, fix some 80-column violations,
and tidy up a few other formatting issues.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74060 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 04:48:43 +00:00
Dan Gohman
40a5a1b39e Extend ScalarEvolution's multiple-exit support to compute exact
trip counts in more cases.

Generalize ScalarEvolution's isLoopGuardedByCond code to recognize
And and Or conditions, splitting the code out into an
isNecessaryCond helper function so that it can evaluate Ands and Ors
recursively, and make SCEVExpander be much more aggressive about
hoisting instructions out of loops.

test/CodeGen/X86/pr3495.ll has an additional instruction now, but
it appears to be due to an arbitrary register allocation difference.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74048 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 01:18:18 +00:00
Dan Gohman
62849c065e Teach GetMinSignBits about SCEVAddExprs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74045 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 01:05:09 +00:00
Dan Gohman
6bbcba18db Move the special cases for constants out of getUnknown and into
createSCEV. Also, recognize UndefValue in createSCEV.

Change getIntegerSCEV's comment to avoid mentioning FP types,
and re-implement it in terms of getConstant instead of getUnknown.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74041 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 00:54:57 +00:00
Dan Gohman
b8be8b70a2 Use ScalarEvolution::getConstant instead of getUnknown to create
SCEVConstants. This cleanup is a step toward letting getUnknown
be simpler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74037 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 00:38:39 +00:00
Dan Gohman
aa551ae10e Include the maximum trip count expression in ScalarEvolution's print output.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74035 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 00:33:16 +00:00
Dan Gohman
4d289bf4af Add an isAllOnesValue utility function, similar to isZero and isOne.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74032 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-24 00:30:26 +00:00
Dan Gohman
91380b7239 Fix a bug in the trip-count computation with And/Or. If either of the
sides is CouldNotCompute, the resulting exact count must be CouldNotCompute.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73920 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 23:28:56 +00:00
Owen Anderson
753ad615f9 Remove the parent pointer from SCEV, since it did not end up being needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73907 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 21:57:23 +00:00
Owen Anderson
372b46cad9 SCEVHandle is no more!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73906 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 21:39:50 +00:00
Dan Gohman
d32f5bf22d Fix some typos that Duncan noticed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73903 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 21:10:22 +00:00
Owen Anderson
08367b6163 Banish global state from ScalarEvolution! SCEV uniquing is now done by tables attached to the ScalarEvolution pass.
This also throws out the SCEV reference counting scheme, as the the SCEVs now have a lifetime controlled by the
ScalarEvolution pass.

Note that SCEVHandle is now a no-op, and will be remove in a future commit.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73892 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 18:25:46 +00:00
Dan Gohman
60e9b0708a Make use of getUMinFromMismatchedTypes when computing backedge-taken
counts for loops with multiple exits, replacing more conservative code
which only handled constants. This is derived from a patch by
Nick Lewycky.

This also fixes llc aborts in ClamAV and others, as
getUMinFromMismatchedTypes takes care of balancing the types before
working with them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73884 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 15:09:28 +00:00
Dan Gohman
c9759e80f4 Add a getUMinFromMismatchedTypes helper function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73883 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 15:03:27 +00:00
Dan Gohman
f9a9a9928c Factor out code for computing umin and smin for SCEV expressions into
helper functions. Based on a patch by Nick Lewycky.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73869 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 03:18:45 +00:00
Dan Gohman
a334aa7a10 Teach ScalarEvolution how to analyze loops with multiple exit
blocks, and also exit blocks with multiple conditions (combined
with (bitwise) ands and ors). It's often infeasible to compute an
exact trip count in such cases, but a useful upper bound can often
be found.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73866 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 00:31:57 +00:00
Dan Gohman
743ab498d8 Delete an unused variable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73865 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-22 00:19:17 +00:00
Dan Gohman
51f53b7f5a Fix ScalarEvolution's backedge-taken count computations to check for
overflow when computing a integer division to round up.

Thanks to Nick Lewycky for noticing this!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73862 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-21 23:46:38 +00:00
Dan Gohman
763bad1a2b Generalize isLoopGuardedByCond's checking to consider two
SCEVUnknowns with identical Instructions to be equal. This allows
it to analze cases such as the attached testcase, where the front-end
has cloned the loop controlling expression. Along with r73805, this
lets IndVarSimplify eliminate all the sign-extend casts in the
loop in the attached testcase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73807 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-20 00:35:32 +00:00
Dan Gohman
3964acc2f4 Use ScalarEvolution's new GetMinSignBits and GetMinLeadingZeros
in the loop backedge-taken count computation of the maximum
possible trip count.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73805 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-20 00:32:22 +00:00
Dan Gohman
2c364ad4a6 Make GetMinTrailingZeros a member function of ScalarEvolution,
so that it can access the TargetData member (when available) and
use ValueTracking.h information to compute information for
SCEVUnknown Values.

Also add GetMinLeadingZeros and GetMinSignBits functions,
with minimal implementations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73794 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-19 23:29:04 +00:00
Dan Gohman
0c689c5e05 Make ScalarEvolution::print print getSCEVAtScope values for
expressions, when interesting.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73776 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-19 17:49:54 +00:00
Owen Anderson
4a7893b452 Add a parent pointer to SCEV, in preparation for getting rid of the global uniquing tables. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73728 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-18 22:25:12 +00:00
Dan Gohman
30fb512e95 Recognize n != 0 ? n : 1 as umax(n, 1). Previously only ULT/UGT/ULE/UGE
comparisons were recognized for umax, but instcombine canonicalizes
unsigned comparisons with zero to this simpler form.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73717 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-18 20:21:07 +00:00
Dan Gohman
6864db6fac Update a comment to reflect the code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73704 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-18 16:24:47 +00:00
Dan Gohman
9e7d9883b0 Fix trailing whitespace from ScalarEvolution::print.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73666 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-18 00:37:45 +00:00
Dan Gohman
820528331f Teach ScalarEvolution how to recognize another xor(and(x, C), C) case.
If C is a single bit and the and gets analyzed as a truncate and
zero-extend, the xor can be represnted as an add.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73664 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-18 00:00:20 +00:00
Dan Gohman
fc3641b07a Delete unnecessary braces.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73663 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-17 23:54:37 +00:00
Dan Gohman
3034c10675 Fix ScalarEvolution's Xor handling to not assume that an And
that gets recognized with a SCEVZeroExtendExpr must be an And
with a low-bits mask. With r73540, this is no longer the case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73594 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-17 01:22:39 +00:00
Dan Gohman
61ffa8e373 Instcombine's ShrinkDemandedConstant may strip bits out of constants,
obscuring what would otherwise be a low-bits mask.  Use ComputeMaskedBits
to compute what ShrinkDemandedConstant knew about to reconstruct a
low-bits mask value.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73540 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-16 19:52:01 +00:00
Dan Gohman
6de29f8d96 Support vector casts in more places, fixing a variety of assertion
failures.

To support this, add some utility functions to Type to help support
vector/scalar-independent code. Change ConstantInt::get and
ConstantFP::get to support vector types, and add an overload to
ConstantInt::get that uses a static IntegerType type, for
convenience.

Introduce a new getConstant method for ScalarEvolution, to simplify
common use cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73431 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-15 22:12:54 +00:00
Dan Gohman
bd59d7b603 Implement more aggressive folding of add operand lists when
they contain multiplications of constants with add operations.
This helps simplify several kinds of things; in particular it
helps simplify expressions like ((-1 * (%a + %b)) + %a) to %b,
as expressions like this often come up in loop trip count
computations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73361 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-14 22:58:51 +00:00
Dan Gohman
7f7c4366ca Check for the short-circuiting condition before performing
the potentially expensive erase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73359 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-14 22:53:57 +00:00
Dan Gohman
4dfad29547 Do compare constant SCEV values in SCEVComplexityCompare, because
even though the order doesn't matter at the top level of an expression,
it does matter when the constant is a subexpression of an n-ary
expression, because n-ary expressions are sorted lexicographically.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73358 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-14 22:51:25 +00:00
Dan Gohman
a82752c9eb Convert several parts of the ScalarEvolution framework to use
SmallVector instead of std::vector.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73357 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-14 22:47:23 +00:00
Dan Gohman
2ce84c8d47 Add a ScalarEvolution::getAnyExtendExpr utility function for performing
extension with unspecified bits.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73293 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-13 15:56:47 +00:00
Dan Gohman
86fbf2fe4c Rename UnknownValue to CouldNotCompute, since it holds an instance of
SCEVCouldNotCompute, and not SCEVUnknown.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72999 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-06 14:37:11 +00:00
Devang Patel
5c06f61e57 Simplify.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72970 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-05 23:08:56 +00:00
Dan Gohman
c965ee223c Remove some unnecessary #includes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72948 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-05 16:32:58 +00:00
Dan Gohman
91bb61a1e2 For the return type of SCEVUDivExpr, use the RHS' type instead of
that of the LHS. It doesn't matter for correctness, but the LHS
is more likely than the RHS to be a pointer type in exotic cases,
and it's more tidy to have it return the integer type.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72424 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-26 17:44:05 +00:00
Dan Gohman
6c0866ca83 Various comment fixes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72376 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-24 23:45:28 +00:00
Dan Gohman
d594e6f034 Change ScalarEvolution::getSCEVAtScope to always return the original value
in the case where a loop exit value cannot be computed, instead of only in
some cases while using SCEVCouldNotCompute in others. This simplifies
getSCEVAtScope's callers.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72375 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-24 23:25:42 +00:00
Dan Gohman
a3035a69f9 Teach SCEV::isLoopInvariant and SCEV::hasComputableLoopEvolution
about the convention from LoopInfo that a null Loop* means the entire
function body.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72152 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-20 01:01:24 +00:00
Dan Gohman
1959b7562e Make SCEVCallbackVH a private nested class inside ScalarEvolution, as
it's an implementation detail.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72122 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-19 19:22:47 +00:00
Dan Gohman
5be18e8476 Teach SCEVExpander to expand arithmetic involving pointers into GEP
instructions. It attempts to create high-level multi-operand GEPs,
though in cases where this isn't possible it falls back to casting
the pointer to i8* and emitting a GEP with that. Using GEP instructions
instead of ptrtoint+arithmetic+inttoptr helps pointer analyses that
don't use ScalarEvolution, such as BasicAliasAnalysis.

Also, make the AddrModeMatcher more aggressive in handling GEPs.
Previously it assumed that operand 0 of a GEP would require a register
in almost all cases. It now does extra checking and can do more
matching if operand 0 of the GEP is foldable. This fixes a problem
that was exposed by SCEVExpander using GEPs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72093 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-19 02:15:55 +00:00
Daniel Dunbar
8c562e2d25 Silence Release-Asserts warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72011 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-18 16:43:04 +00:00