Commit Graph

666 Commits

Author SHA1 Message Date
Andrew Trick 77c55428fa Use consistent terminology for loop exit/exiting blocks. Name change only.
llvm-svn: 136677
2011-08-02 04:23:35 +00:00
Andrew Trick 3ca3f98c2c SCEV: Added a data structure for storing not-taken info per loop
exit. Added an interfaces for querying either the loop's exact/max
backedge taken count or a specific loop exit's not-taken count.

llvm-svn: 136100
2011-07-26 17:19:55 +00:00
Jay Foad f4b14a2b0d Use ArrayRef in ConstantFoldInstOperands and ConstantFoldCall.
llvm-svn: 135477
2011-07-19 13:32:40 +00:00
Chris Lattner 229907cd11 land David Blaikie's patch to de-constify Type, with a few tweaks.
llvm-svn: 135375
2011-07-18 04:54:35 +00:00
Andrew Trick 8ef3ad049d SCEV: missing null check fix for r132360, dragonegg crash.
llvm-svn: 132416
2011-06-01 19:14:56 +00:00
Andrew Trick 812276eed4 scev: Better sign-extend removal. Normalize postincrement recurrences
so that their sign extended forms are congruent when no overflow occurs.

llvm-svn: 132360
2011-05-31 21:17:47 +00:00
Dan Gohman 0daf687e1d Change a few std::maps to DenseMaps.
llvm-svn: 131088
2011-05-09 18:44:09 +00:00
Andrew Trick 7d1eea86d9 Corrects an old, old typo in a case that doesn't seem to be reached in practice.
llvm-svn: 130316
2011-04-27 18:17:36 +00:00
Andrew Trick 01eff820ae Test case and comment for PR9633.
llvm-svn: 130294
2011-04-27 05:42:17 +00:00
Andrew Trick 759ba0802d Fix for PR9633 [indvars] Assertion `isa<X>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
Added a type check in ScalarEvolution::computeSCEVAtScope to handle the case in which operands of an
AddRecExpr in the current scope are folded.

llvm-svn: 130271
2011-04-27 01:21:25 +00:00
Dan Gohman 6acd95b3c1 Fix an iterator invalidation bug.
llvm-svn: 130166
2011-04-25 22:48:29 +00:00
Chris Lattner 0ab5e2cded Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129558
2011-04-15 05:18:47 +00:00
Andrew Trick 87716c93c2 Added isValidRewrite() to check the result of ScalarEvolutionExpander.
SCEV may generate expressions composed of multiple pointers, which can
lead to invalid GEP expansion. Until we can teach SCEV to follow strict
pointer rules, make sure no bad GEPs creep into IR.
Fixes rdar://problem/9038671.

llvm-svn: 127839
2011-03-17 23:51:11 +00:00
Andrew Trick a34f1b1f10 Remove getMinusSCEVForExitTest().
This function performed acrobatics to prove no-self-wrap, which we now
have for free.

llvm-svn: 127643
2011-03-15 01:16:14 +00:00
Andrew Trick f6b01ff422 Propagate SCEV no-wrap flags whenever possible.
This needs review.

llvm-svn: 127638
2011-03-15 00:37:00 +00:00
Andrew Trick e92dcceab7 Negating a recurrence preserves no-self-wrap.
llvm-svn: 127593
2011-03-14 17:38:54 +00:00
Andrew Trick f1781db622 HowFarToZero can compute a trip count as long as the recurrence has no-self-wrap.
llvm-svn: 127591
2011-03-14 17:28:02 +00:00
Andrew Trick 8b55b736b1 Added SCEV::NoWrapFlags to manage unsigned, signed, and self wrap
properties.
Added the self-wrap flag for SCEV::AddRecExpr.
A slew of temporary FIXMEs indicate the intention of the no-self-wrap flag
without changing behavior in this revision.

llvm-svn: 127590
2011-03-14 16:50:06 +00:00
Andrew Trick 2afa325811 When SCEV can determine the loop test is X < X, set ExactBECount=0.
When ExactBECount is a constant, use it for MaxBECount.
When MaxBECount cannot be computed, replace it with ExactBECount.
Fixes PR9424.

llvm-svn: 127342
2011-03-09 17:29:58 +00:00
Andrew Trick 2a3b71684a whitespace
llvm-svn: 127340
2011-03-09 17:23:39 +00:00
Chris Lattner 4f23f2be15 teach SCEV that the scale and addition of an inbounds gep don't NSW.
This fixes a FIXME in scev-aa.ll (allowing a new no-alias result) and
generally makes things more precise.

llvm-svn: 125449
2011-02-13 03:14:49 +00:00
Chris Lattner 7936a8a488 Per discussion with Dan G, inbounds geps *certainly* can have
unsigned overflow (e.g. "gep P, -1"), and while they can have
signed wrap in theoretical situations, modelling an AddRec as
not having signed wrap is going enough for any case we can 
think of today.  In the future if this isn't enough, we can
revisit this.  Modeling them as having NUW isn't causing any
known problems either FWIW.

llvm-svn: 125410
2011-02-11 21:43:33 +00:00
Nick Lewycky d9e6b4a8ff Fix memory corruption. If one of the SCEV creation functions calls another but
doesn't return immediately after then the insert position in UniqueSCEVs will
be out of date. No test because this is a memory corruption issue. Fixes PR9051!

llvm-svn: 124282
2011-01-26 08:40:22 +00:00
Dan Gohman 3ac8cd614f Add a comment.
llvm-svn: 124126
2011-01-24 17:54:18 +00:00
Nick Lewycky d4192f71b5 Simplify some code with no functionality change. Make the test a lot more
robust against smarter optimizations, using the power of FileCheck.

llvm-svn: 124081
2011-01-23 20:06:05 +00:00
Nick Lewycky bc98f5b78e Use value ranges to fold ext(trunc) in SCEV when possible.
llvm-svn: 124062
2011-01-23 06:20:19 +00:00
Nick Lewycky b32c8943e6 Have SCEV turn sext(x) into zext(x) when x is s>= 0. This applies many times in
"make check" alone.

llvm-svn: 124046
2011-01-22 22:06:21 +00:00
Nick Lewycky 5c901f3489 Similarly, analyze truncate through multiply.
llvm-svn: 123842
2011-01-19 18:56:00 +00:00
Nick Lewycky 5143f0f09b Add a missed SCEV fold that is required to continue analyzing the IR produced
by indvars through the scev expander.

trunc(add x, y) --> add(trunc x, y). Currently SCEV largely folds the other way
which is probably wrong, but preserved to minimize churn. Instcombine doesn't
do this fold either, demonstrating a missed optz'n opportunity on code doing
add+trunc+add.

llvm-svn: 123838
2011-01-19 16:59:46 +00:00
Nick Lewycky e9ea75e3fc Add a missing SCEV simplification sext(zext x) --> zext x.
llvm-svn: 123832
2011-01-19 15:56:12 +00:00
Chris Lattner d30de95520 some comment improvements.
llvm-svn: 123243
2011-01-11 17:11:59 +00:00
Eric Christopher 23bf3bafb7 Temporarily revert 123133, it's causing some regressions and I'm trying
to get a testcase.

llvm-svn: 123225
2011-01-11 09:02:09 +00:00
Chris Lattner 23109cb319 the GEP faq says that only inbounds geps are guaranteed to not overflow.
llvm-svn: 123218
2011-01-11 06:44:41 +00:00
Chris Lattner 67f82314af add a fixme: ir isn't expressive enough.
llvm-svn: 123139
2011-01-09 23:02:10 +00:00
Chris Lattner 28f140a33e Step #4 in improving trip count analysis: HowFarToZero can analyze
NUW AddRec's much more aggressively.  We now get a trip count
for @test2 in nsw.ll

llvm-svn: 123138
2011-01-09 22:58:47 +00:00
Chris Lattner dff679f4b6 rearrange some code, no functionality change.
llvm-svn: 123136
2011-01-09 22:39:48 +00:00
Chris Lattner a44274cb4f Step #3 to improving trip count analysis: If we fold
a + {b,+,stride} into {a+b,+,stride}  (because a is LIV),
then the resultant AddRec is NUW/NSW if the client says it
is.

llvm-svn: 123133
2011-01-09 22:31:26 +00:00
Chris Lattner fc87752d55 Step #2 to improve trip count analysis for loops like this:
void f(int* begin, int* end) { std::fill(begin, end, 0); }

which turns into a != exit expression where one pointer is
strided and (thanks to step #1) known to not overflow, and 
the other is loop invariant.

The observation here is that, though the IV is strided by
4 in this case, that the IV *has* to become equal to the
end value.  It cannot "miss" the end value by stepping over
it, because if it did, the strided IV expression would
eventually wrap around.

Handle this by turning A != B into "A-B != 0" where the A-B
part is known to be NUW.

llvm-svn: 123131
2011-01-09 22:26:35 +00:00
Chris Lattner 10223a3fbf teach SCEV analysis of PHI nodes that PHI recurences formed
with GEP instructions are always NUW, because PHIs cannot wrap
the end of the address space.

llvm-svn: 123105
2011-01-09 02:28:48 +00:00
Chris Lattner a337f5ec5c reduce indentation. Print <nuw> and <nsw> when dumping SCEV AddRec's
that have the bit set.

llvm-svn: 123104
2011-01-09 02:16:18 +00:00
Jay Foad 583abbc4df PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and
zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.

llvm-svn: 121120
2010-12-07 08:25:19 +00:00
Jay Foad 25a5e4ca1f PR5207: Rename overloaded APInt methods set(), clear(), flip() to
setAllBits(), setBit(unsigned), etc.

llvm-svn: 120564
2010-12-01 08:53:58 +00:00
Benjamin Kramer ddd1b7b801 Simplify code. No change in functionality.
llvm-svn: 119908
2010-11-20 18:43:35 +00:00
Benjamin Kramer c77ebcc9a5 Silence warning about an uninitialized variable.
llvm-svn: 119800
2010-11-19 11:37:26 +00:00
Duncan Sands aef146b890 Factor code for testing whether replacing one value with another
preserves LCSSA form out of ScalarEvolution and into the LoopInfo
class.  Use it to check that SimplifyInstruction simplifications
are not breaking LCSSA form.  Fixes PR8622.

llvm-svn: 119727
2010-11-18 19:59:41 +00:00
Dan Gohman 8ea83d81e0 Introduce memoization for ScalarEvolution dominates and properlyDominates
queries, and SCEVExpander getRelevantLoop queries.

llvm-svn: 119595
2010-11-18 00:34:22 +00:00
Dan Gohman 7e6b393e66 Factor out the code for purging a SCEV from all the various memoization maps.
Some of these maps may merge in the future, but for now it's convenient to have
a utility function for them.

llvm-svn: 119587
2010-11-17 23:28:48 +00:00
Dan Gohman 7ee1bbb76c Merge the implementations of isLoopInvariant and hasComputableLoopEvolution, and
memoize the results. This improves compile time in code which highly complex
expressions which get queried many times.

llvm-svn: 119584
2010-11-17 23:21:44 +00:00
Dan Gohman 534749bf70 Make SCEV::getType() and SCEV::print non-virtual. Move SCEV::hasOperand
to ScalarEvolution. Delete SCEV::~SCEV. SCEV is no longer virtual.

llvm-svn: 119578
2010-11-17 22:27:42 +00:00
Dan Gohman 20d9ce21ef Move SCEV::dominates and properlyDominates to ScalarEvolution.
llvm-svn: 119570
2010-11-17 21:41:58 +00:00
Dan Gohman afd6db9932 Move SCEV::isLoopInvariant and hasComputableLoopEvolution to be member
functions of ScalarEvolution, in preparation for memoization and
other optimizations.

llvm-svn: 119562
2010-11-17 21:23:15 +00:00
Duncan Sands 39d77131a1 Before replacing a phi node with a different value, it
needs to be checked that this won't break LCSSA form.
Change the existing checking method to a more direct one:
rather than seeing if all predecessors belong to the loop,
check that the replacing value is either not in any loop or
is in a loop that contains the phi node.

llvm-svn: 119556
2010-11-17 20:49:12 +00:00
Dan Gohman d3a32ae4c8 Verify SCEVAddRecExpr's invariant in ScalarEvolution::getAddRecExpr
instead of in SCEVAddRecExpr's constructor, in preparation for an
upcoming change.

llvm-svn: 119554
2010-11-17 20:48:38 +00:00
Dan Gohman ed75631743 Fix ScalarEvolution's range memoization to avoid using a
default ctor with ConstantRange.

llvm-svn: 119550
2010-11-17 20:23:08 +00:00
Duncan Sands d06f50e2db Have ScalarEvolution use SimplifyInstruction rather than hasConstantValue.
While there, add a note about an inefficiency I noticed.

llvm-svn: 119458
2010-11-17 04:18:45 +00:00
Dan Gohman 761065e3b7 Memoize results from ScalarEvolution's getUnsignedRange and getSignedRange.
This fixes some extreme compile times on unrolled sha512 code.

llvm-svn: 119455
2010-11-17 02:44:44 +00:00
Dan Gohman dcb354b234 Make ScalarEvolution::forgetLoop forget all contained loops too, because
they may have ValuesAtScopes map entries referencing their outer loops.
This fixes a user-after-free reported in PR8471.

llvm-svn: 117698
2010-10-29 20:16:10 +00:00
Owen Anderson 6c18d1aac0 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.

llvm-svn: 116820
2010-10-19 17:21:58 +00:00
Owen Anderson 8ac477ffb5 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.

llvm-svn: 116334
2010-10-12 19:48:12 +00:00
Owen Anderson df7a4f2515 Now with fewer extraneous semicolons!
llvm-svn: 115996
2010-10-07 22:25:06 +00:00
Dan Gohman 8e4c19ac44 Don't add the operand count to SCEV uniquing data; FoldingSetNodeID
already knows its own length, so this is redundant.

llvm-svn: 115521
2010-10-04 17:24:08 +00:00
Dan Gohman 47308d5da3 Reapply r112432, now that the real problem is addressed.
llvm-svn: 112667
2010-08-31 22:53:17 +00:00
Dan Gohman f01a5eed1e Reapply r112433, now that the real problem is addressed.
llvm-svn: 112666
2010-08-31 22:52:12 +00:00
Dan Gohman aabfc52790 Revert r110916. This patch is buggy because the code inside the
inner loop doesn't update all the variables in the outer loop.

llvm-svn: 112665
2010-08-31 22:50:31 +00:00
Dan Gohman 90f29bcd90 Revert r112432. It appears to be exposing a problem in the emacs build.
llvm-svn: 112638
2010-08-31 20:58:44 +00:00
Dan Gohman 444c24a9f0 Speculatively revert r112433.
llvm-svn: 112608
2010-08-31 17:56:47 +00:00
Dan Gohman d1da5cdfee Restructure the {A,+,B}<L> * {C,+,D}<L> folding so that it folds
all applicable addrecs before recursing on getMulExpr, instead of
recursing on getMulExpr for each one.

llvm-svn: 112433
2010-08-29 15:16:58 +00:00
Dan Gohman 3e6fc18943 Batch up subtracts along with adds, when analyzing long chains of
operations.

llvm-svn: 112432
2010-08-29 15:10:06 +00:00
Dan Gohman 7712d2900d Micro-optimize GroupByComplexity.
llvm-svn: 112431
2010-08-29 15:07:13 +00:00
Dan Gohman 0f2de01355 Hold AddRec->getLoop() in a variable, to make the Mul code more consistent
with the Add code.

llvm-svn: 112430
2010-08-29 14:55:19 +00:00
Dan Gohman 028c18158a Rename a variable, for consistency.
llvm-svn: 112429
2010-08-29 14:53:34 +00:00
Dan Gohman 28a84d4ba1 Use iterators instead of indices.
llvm-svn: 112428
2010-08-29 14:52:02 +00:00
Dan Gohman fe22f1d3cc Fix an index calculation thinko.
llvm-svn: 112337
2010-08-28 00:39:27 +00:00
Dan Gohman 15871f23e3 When merging adjacent operands, scan ahead and merge all equal
adjacent operands at once, instead of just two at a time.

llvm-svn: 112299
2010-08-27 21:39:59 +00:00
Dan Gohman c866bf4fec Make the {A,+,B}<L> + {C,+,D}<L> --> Other + {A+C,+,B+D}<L>
transformation collect all the addrecs with the same loop
add combine them at once rather than starting everything over
at the first chance.

llvm-svn: 112290
2010-08-27 20:45:56 +00:00
Dan Gohman 9bad2fb378 Switch ScalarEvolution's main Value*->SCEV* map from std::map
to DenseMap.

llvm-svn: 112281
2010-08-27 18:55:03 +00:00
Dan Gohman 2706567c5c Optimize SCEVComplexityCompare. Use a 3-way return instead of a 2-way
return to avoid needing two calls to test for equivalence, and sort
addrecs by their degree before examining their operands.

llvm-svn: 112267
2010-08-27 15:26:01 +00:00
Dan Gohman 797a1dbb1c To create a copy of a SmallVector with an element removed from the
middle, copy the elements in two groups, rather than copying all the
elements and then doing an erase on the middle of the result. These
are SmallVectors, so we shouldn't expect to hit dynamic allocation
in the common case.

llvm-svn: 111151
2010-08-16 16:57:24 +00:00
Dan Gohman 0d0cc18af5 Tidy whitespace.
llvm-svn: 111147
2010-08-16 16:34:09 +00:00
Dan Gohman c29eeaecec Add a comment.
llvm-svn: 111145
2010-08-16 16:31:39 +00:00
Dan Gohman 7eac4961d7 Use const_iterator in a few places.
llvm-svn: 111144
2010-08-16 16:30:01 +00:00
Dan Gohman 74c61503b1 Use iterators instead of indices in a few more places.
llvm-svn: 111143
2010-08-16 16:27:53 +00:00
Dan Gohman f29618236e Micro-optimize SCEVConstant comparison.
llvm-svn: 111142
2010-08-16 16:25:35 +00:00
Dan Gohman 3688ea5c7d Move SCEVNAryExpr's virtual member functions out of line, and convert
them to iterators.

llvm-svn: 111140
2010-08-16 16:21:27 +00:00
Dan Gohman d6925bbe0d Use iterators instead of indices in simple cases.
llvm-svn: 111138
2010-08-16 16:16:11 +00:00
Dan Gohman b6c773ec2e Avoid gratuitous inefficiency in ifndef NDEBUG code.
llvm-svn: 111137
2010-08-16 16:13:54 +00:00
Dan Gohman e5fb1036e6 Make one getAddExpr call when analyzing a+b+c+d+e+... instead of one
for each add instruction. Ditto for Mul.

llvm-svn: 111136
2010-08-16 16:03:49 +00:00
Dan Gohman b094b39111 Delete an unused function.
llvm-svn: 111135
2010-08-16 15:57:14 +00:00
Dan Gohman 0c436ab356 Various optimizations. Don't compare two loops' depths
when they are the same loop. Don't compare two instructions'
loop depths when they are in the same block.

llvm-svn: 111045
2010-08-13 21:24:58 +00:00
Dan Gohman 63c020a210 When testing whether one loop contains another, test this directly
rather than testing whether the loop contains the other's header.

llvm-svn: 111039
2010-08-13 20:23:25 +00:00
Dan Gohman 3324b9ec67 Add a const.
llvm-svn: 111038
2010-08-13 20:17:27 +00:00
Dan Gohman cf32f2bde1 When creating a symmetric SCEV with a constant operand, put
the constant operand on the left, as that's where ScalarEvolution
will end up canonicalizing to.

llvm-svn: 111037
2010-08-13 20:17:14 +00:00
Dan Gohman ec0120a123 An add recurrence is loop-invariant in any loop inside of its
associated loop. This avoids potentially expensive traversals
of the add recurrence's operands.

llvm-svn: 111034
2010-08-13 20:11:39 +00:00
Dan Gohman 2de47777f4 Optimize ScalarEvolution::getAddExpr's operand factoring code by
having it finish processing all of the muliply operands before
starting the whole getAddExpr process over again, instead of
immediately after the first simplification.

llvm-svn: 110916
2010-08-12 15:00:23 +00:00
Dan Gohman 157847f5d1 Hoist some loop-invariant code out of a hot loop.
llvm-svn: 110915
2010-08-12 14:52:55 +00:00
Dan Gohman e67b287451 Optimize ScalarEvolution::getAddExpr's duplicate operand detection
by having it finish processing the whole operand list before
starting the whole getAddExpr process over again, instead of
immediately after the first duplicate is found.

llvm-svn: 110914
2010-08-12 14:46:54 +00:00
Dan Gohman f7495f286a When analyzing loop exit conditions combined with and and or, don't
make any assumptions about when the two conditions will agree on when
to permit the loop to exit. This fixes PR7845.

llvm-svn: 110758
2010-08-11 00:12:36 +00:00
Dan Gohman e18c2d6f99 Rename and reorder the arguments to isImpliedCond, for consistency and clarity.
llvm-svn: 110750
2010-08-10 23:46:30 +00:00
Owen Anderson a7aed18624 Reapply r110396, with fixes to appease the Linux buildbot gods.
llvm-svn: 110460
2010-08-06 18:33:48 +00:00
Owen Anderson bda59bd247 Revert r110396 to fix buildbots.
llvm-svn: 110410
2010-08-06 00:23:35 +00:00