1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-26 22:42:46 +02:00
Commit Graph

842 Commits

Author SHA1 Message Date
David Majnemer
b5ae33d9e3 ScalarEvolution: Construct SCEVDivision's Derived type instead of itself
SCEVDivision::divide constructed an object of SCEVDivision<Derived>
instead of Derived.  divide would call visit which would cast the
SCEVDivision<Derived> to type Derived.  As it happens,
SCEVDivision<Derived> and Derived currently have the same layout but
this is fragile and grounds for UB.

Instead, just construct Derived.  No functional change intended.

llvm-svn: 222126
2014-11-17 11:27:45 +00:00
David Majnemer
f2223dee20 ScalarEvolution: Introduce SCEVSDivision and SCEVUDivision
It turns out that not all users of SCEVDivision want the same
signedness.  Let the users determine which operation they'd like by
explicitly choosing SCEVUDivision or SCEVSDivision.

findArrayDimensions and computeAccessFunctions will use SCEVSDivision
while HowFarToZero will use SCEVUDivision.

llvm-svn: 222104
2014-11-16 20:35:19 +00:00
David Majnemer
7e29d637c6 ScalarEvolution: HowFarToZero was wrongly using signed division
HowFarToZero was supposed to use unsigned division in order to calculate
the backedge taken count.  However, SCEVDivision::divide performs signed
division.  Unless I am mistaken, no users of SCEVDivision actually want
signed arithmetic: switch to udiv and urem.

This fixes PR21578.

llvm-svn: 222093
2014-11-16 07:30:35 +00:00
Sanjoy Das
337f78bb79 Teach ScalarEvolution to sharpen range information.
If x is known to have the range [a, b), in a loop predicated by (icmp
ne x, a) its range can be sharpened to [a + 1, b).  Get
ScalarEvolution and hence IndVars to exploit this fact.

This change triggers an optimization to widen-loop-comp.ll, so it had
to be edited to get it to pass.

This change was originally landed in r219834 but had a bug and broke
ASan. It was reverted in r219878, and is now being re-landed after
fixing the original bug.

phabricator: http://reviews.llvm.org/D5639
reviewed by: atrick

llvm-svn: 221839
2014-11-13 00:00:58 +00:00
Duncan P. N. Exon Smith
8770505e4e Revert "IR: MDNode => Value"
Instead, we're going to separate metadata from the Value hierarchy.  See
PR21532.

This reverts commit r221375.
This reverts commit r221373.
This reverts commit r221359.
This reverts commit r221167.
This reverts commit r221027.
This reverts commit r221024.
This reverts commit r221023.
This reverts commit r220995.
This reverts commit r220994.

llvm-svn: 221711
2014-11-11 21:30:22 +00:00
Duncan P. N. Exon Smith
7004fd9aac IR: MDNode => Value: Instruction::getMetadata()
Change `Instruction::getMetadata()` to return `Value` as part of
PR21433.

Update most callers to use `Instruction::getMDNode()`, which wraps the
result in a `cast_or_null<MDNode>`.

llvm-svn: 221024
2014-11-01 00:10:31 +00:00
Bradley Smith
3e03fb9d20 [SCEV] Improve Scalar Evolution's use of no {un,}signed wrap flags
In a case where we have a no {un,}signed wrap flag on the increment, if
RHS - Start is constant then we can avoid inserting a max operation bewteen
the two, since we can statically determine which is greater.

This allows us to unroll loops such as:

 void testcase3(int v) {
   for (int i=v; i<=v+1; ++i)
     f(i);
 }

llvm-svn: 220960
2014-10-31 11:40:32 +00:00
Sanjoy Das
0399f6122b Revert "r219834 - Teach ScalarEvolution to sharpen range information"
This change breaks the asan buildbots:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/13468

llvm-svn: 219878
2014-10-15 23:46:04 +00:00
Sanjoy Das
0ebb55a70b Teach ScalarEvolution to sharpen range information.
If x is known to have the range [a, b) in a loop predicated by (icmp
ne x, a), its range can be sharpened to [a + 1, b).  Get
ScalarEvolution and hence IndVars to exploit this fact.
    
This change triggers an optimization to widen-loop-comp.ll, so it had
to be edited to get it to pass.

phabricator: http://reviews.llvm.org/D5639
llvm-svn: 219834
2014-10-15 19:25:28 +00:00
Chandler Carruth
9e809b8dad [SCEV] Add some asserts to the recently improved trip count computation
routines and fix all of the bugs they expose.

I hit a test case that crashed even without these asserts due to passing
a non-exiting latch to the ExitingBlock parameter of the trip count
computation machinery. However, when I add the nice asserts, it turns
out we have plenty of coverage of these bugs, they just didn't manifest
in crashers.

The core problem seems to stem from an assumption that the latch *is*
the exiting block. While this is often true, and somewhat the "normal"
way to think about loops, it isn't necessarily true. The correct way to
call the trip count routines in a *generic* fashion (that is, without
a particular exit in mind) is to just use the loop's single exiting
block if it has one. The trip count can't be computed generically unless
it does. This works great for the loop vectorizer. The loop unroller
actually *wants* to select the latch when it has to chose between
multiple exits because for unrolling it is the latch trips that matter.
But if this is the desire, it needs to explicitly guard for non-exiting
latches and check for the generic trip count in that case.

I've added the asserts, and added convenience APIs for querying the trip
count generically that check for a single exit block. I've kept the APIs
consistent between computing trip count and trip multiples.

Thansk to Mark for the help debugging and tracking down the *right* fix
here!

llvm-svn: 219550
2014-10-11 00:12:11 +00:00
Sanjoy Das
c03606ae56 This patch teaches ScalarEvolution to pick and use !range metadata.
It also makes it more aggressive in querying range information by
adding a call to isKnownPredicateWithRanges to
isLoopBackedgeGuardedByCond and isLoopEntryGuardedByCond.

phabricator: http://reviews.llvm.org/D5638

Reviewed by: atrick, hfinkel

llvm-svn: 219532
2014-10-10 21:22:34 +00:00
Mark Heffernan
fdfe8b7008 This patch de-pessimizes the calculation of loop trip counts in
ScalarEvolution in the presence of multiple exits. Previously all
loops exits had to have identical counts for a loop trip count to be
considered computable. This pessimization was implemented by calling
getBackedgeTakenCount(L) rather than getExitCount(L, ExitingBlock)
inside of ScalarEvolution::getSmallConstantTripCount() (see the FIXME
in the comments of that function). The pessimization was added to fix
a corner case involving undefined behavior (pr/16130). This patch more
precisely handles the undefined behavior case allowing the pessimization
to be removed.

ControlsExit replaces IsSubExpr to more precisely track the case where
undefined behavior is expected to occur. Because undefined behavior is
tracked more precisely we can remove MustExit from ExitLimit. MustExit
was used to track the case where the limit was computed potentially
assuming undefined behavior even if undefined behavior didn't necessarily
occur.

llvm-svn: 219517
2014-10-10 17:39:11 +00:00
Hal Finkel
56525dc578 Make use @llvm.assume for loop guards in ScalarEvolution
This adds a basic (but important) use of @llvm.assume calls in ScalarEvolution.
When SE is attempting to validate a condition guarding a loop (such as whether
or not the loop count can be zero), this check should also include dominating
assumptions.

llvm-svn: 217348
2014-09-07 21:37:59 +00:00
Hal Finkel
f8bb9b78cf Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.)
This change, which allows @llvm.assume to be used from within computeKnownBits
(and other associated functions in ValueTracking), adds some (optional)
parameters to computeKnownBits and friends. These functions now (optionally)
take a "context" instruction pointer, an AssumptionTracker pointer, and also a
DomTree pointer, and most of the changes are just to pass this new information
when it is easily available from InstSimplify, InstCombine, etc.

As explained below, the significant conceptual change is that known properties
of a value might depend on the control-flow location of the use (because we
care that the @llvm.assume dominates the use because assumptions have
control-flow dependencies). This means that, when we ask if bits are known in a
value, we might get different answers for different uses.

The significant changes are all in ValueTracking. Two main changes: First, as
with the rest of the code, new parameters need to be passed around. To make
this easier, I grouped them into a structure, and I made internal static
versions of the relevant functions that take this structure as a parameter. The
new code does as you might expect, it looks for @llvm.assume calls that make
use of the value we're trying to learn something about (often indirectly),
attempts to pattern match that expression, and uses the result if successful.
By making use of the AssumptionTracker, the process of finding @llvm.assume
calls is not expensive.

Part of the structure being passed around inside ValueTracking is a set of
already-considered @llvm.assume calls. This is to prevent a query using, for
example, the assume(a == b), to recurse on itself. The context and DT params
are used to find applicable assumptions. An assumption needs to dominate the
context instruction, or come after it deterministically. In this latter case we
only handle the specific case where both the assumption and the context
instruction are in the same block, and we need to exclude assumptions from
being used to simplify their own ephemeral values (those which contribute only
to the assumption) because otherwise the assumption would prove its feeding
comparison trivial and would be removed.

This commit adds the plumbing and the logic for a simple masked-bit propagation
(just enough to write a regression test). Future commits add more patterns
(and, correspondingly, more regression tests).

llvm-svn: 217342
2014-09-07 18:57:58 +00:00
Nick Lewycky
ea9374b1f2 Remove an errant outer loop that contains nothing but an inner loop over exactly the same elements. While no functionality is change intended (and hence there are no changes to tests), you don't want to skip this revision if bisecting for errors.
llvm-svn: 216864
2014-09-01 05:17:15 +00:00
Duncan P. N. Exon Smith
2ae51d315c Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges."
This reverts commit r213474 (and r213475), which causes a miscompile on
a stage2 LTO build.  I'll reply on the list in a moment.

llvm-svn: 213562
2014-07-21 17:06:51 +00:00
Manuel Jacob
8e924ddc40 [C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges.
Summary: This patch introduces two new iterator ranges and updates existing code to use it.  No functional change intended.

Test Plan: All tests (make check-all) still pass.

Reviewers: dblaikie

Reviewed By: dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4481

llvm-svn: 213474
2014-07-20 09:10:11 +00:00
Tobias Grosser
e914a50dc9 ScalarEvolution: Derive element size from the type of the loaded element
Before, we where looking at the size of the pointer type that specifies the
location from which to load the element. This did not make any sense at all.

This change fixes a bug in the delinearization where we failed to delinerize
certain load instructions.

llvm-svn: 210435
2014-06-08 19:21:20 +00:00
Sebastian Pop
e038cb3e5a implement missing SCEVDivision case
without this case we would end on an infinite recursion: the remainder is zero,
so Numerator - Remainder is equal to Numerator and so we would recursively ask
for the division of Numerator by Denominator.

llvm-svn: 209838
2014-05-29 19:44:09 +00:00
Sebastian Pop
a5d17facf7 fail to find dimensions when ElementSize is nullptr
when ScalarEvolution::getElementSize returns nullptr it is safe to early return
in ScalarEvolution::findArrayDimensions such that we avoid later problems when
we try to divide the terms by ElementSize.

llvm-svn: 209837
2014-05-29 19:44:05 +00:00
Sebastian Pop
6efdf0e296 avoid type mismatch when building SCEVs
This is a corner case I have stumbled upon when dealing with ARM64 type
conversions. I was not able to extract a testcase for the community codebase to
fail on. The patch conservatively discards a division that would have ended up
in an ICE due to a type mismatch when building a multiply expression. I have
also added code to a place that builds add expressions and in which we should be
careful not to pass in operands of different types.

llvm-svn: 209694
2014-05-27 22:42:00 +00:00
Sebastian Pop
fa763d3c07 do not use the GCD to compute the delinearization strides
We do not need to compute the GCD anymore after we removed the constant
coefficients from the terms: the terms are now all parametric expressions and
there is no need to recognize constant terms that divide only a subset of the
terms. We only rely on the size of the terms, i.e., the number of operands in
the multiply expressions, to sort the terms and recognize the parametric
dimensions.

llvm-svn: 209693
2014-05-27 22:41:56 +00:00
Sebastian Pop
721b704445 remove BasePointer before delinearizing
No functional change is intended: instead of relying on the delinearization to
come up with the base pointer as a remainder of the divisions in the
delinearization, we just compute it from the array access and use that value.
We substract the base pointer from the SCEV to be delinearized and that
simplifies the work of the delinearizer.

llvm-svn: 209692
2014-05-27 22:41:51 +00:00
Sebastian Pop
1664c3c2ec remove constant terms
The delinearization is needed only to remove the non linearity induced by
expressions involving multiplications of parameters and induction variables.
There is no problem in dealing with constant times parameters, or constant times
an induction variable.

For this reason, the current patch discards all constant terms and multipliers
before running the delinearization algorithm on the terms. The only thing
remaining in the term expressions are parameters and multiply expressions of
parameters: these simplified term expressions are passed to the array shape
recognizer that will not recognize constant dimensions anymore: these will be
recognized as different strides in parametric subscripts.

The only important special case of a constant dimension is the size of elements.
Instead of relying on the delinearization to infer the size of an element,
compute the element size from the base address type. This is a much more precise
way of computing the element size than before, as we would have mixed together
the size of an element with the strides of the innermost dimension.

llvm-svn: 209691
2014-05-27 22:41:45 +00:00
Michael Zolotukhin
406287c5b7 Some cleanup for r209568.
llvm-svn: 209634
2014-05-26 14:49:46 +00:00
Michael Zolotukhin
df83a19a09 Implement sext(C1 + C2*X) --> sext(C1) + sext(C2*X) and
sext{C1,+,C2} --> sext(C1) + sext{0,+,C2} transformation in Scalar
Evolution.

That helps SLP-vectorizer to recognize consecutive loads/stores.

<rdar://problem/14860614>

llvm-svn: 209568
2014-05-24 08:09:57 +00:00
Andrew Trick
3b4463f718 Fix and improve SCEV ComputeBackedgeTankCount.
This is a follow-up to r209358: PR19799: Indvars miscompile due to an
incorrect max backedge taken count from SCEV.

That fix was incomplete as pointed out by Arnold and Michael Z. The
code was also too confusing. It needed a careful rewrite with more
unit tests. This version will also happen to optimize more cases.

<rdar://17005101> PR19799: Indvars miscompile...

llvm-svn: 209545
2014-05-23 19:47:13 +00:00
Justin Bogner
5e6887dc27 ScalarEvolution: Fix handling of AddRecs in isKnownPredicate
ScalarEvolution::isKnownPredicate() can wrongly reduce a comparison
when both the LHS and RHS are SCEVAddRecExprs. This checks that both
LHS and RHS are guarded in the case when both are SCEVAddRecExprs.

The test case is against indvars because I could not find a way to
directly test SCEV.

Patch by Sanjay Patel!

llvm-svn: 209487
2014-05-23 00:06:56 +00:00
Andrew Trick
102d4404fb Fix a bug in SCEV's backedge taken count computation from my prior fix in Jan.
This has to do with the trip count computation for loops with multiple
exits, which is quite subtle. Most passes just ask for a single trip
count number, so we must be conservative assuming any exit could be
taken.  Normally, we rely on the "exact" trip count, which was
correctly given as "unknown". However, SCEV also gives a "max"
back-edge taken count. The loops max BE taken count is conservatively
a maximum over the max of each exit's non-exiting iterations
count. Note that some exit tests can be skipped so the max loop
back-edge taken count can actually exceed the max non-exiting
iterations for some exits. However, when we know the loop *latch*
cannot be skipped, we can directly use its max taken count
disregarding other exits. I previously took the minimum here without
checking whether the other exit could be skipped. The correct, and
simpler thing to do here is just to directly use the loop latch's max
non-exiting iterations as the loops max back-edge count.

In the problematic test case, the first loop exit had a max of zero
non-exiting iterations, but could be skipped. The loop latch was known
not to be skipped but had max of one non-exiting iteration. We
incorrectly claimed the loop back-edge could be taken zero times, when
it is actually taken one time.

Fixes Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count.
Loop %for.body.i: max backedge-taken count is 1.

llvm-svn: 209358
2014-05-22 00:37:03 +00:00
Jay Foad
e0eac700cb Rename ComputeMaskedBits to computeKnownBits. "Masked" has been
inappropriate since it lost its Mask parameter in r154011.

llvm-svn: 208811
2014-05-14 21:14:37 +00:00
Sebastian Pop
25e94ba142 use nullptr instead of NULL
llvm-svn: 208622
2014-05-12 20:11:01 +00:00
Sebastian Pop
de2f65cfdd do not assert when delinearization fails
llvm-svn: 208615
2014-05-12 19:01:53 +00:00
Sebastian Pop
28499bfbb2 use isZero()
llvm-svn: 208614
2014-05-12 19:01:49 +00:00
Benjamin Kramer
28edee20f3 SCEV: Use range-based for loop and fold variable into assert.
llvm-svn: 208476
2014-05-10 17:47:18 +00:00
Sebastian Pop
f6b4cc99cd move findArrayDimensions to ScalarEvolution
we do not use the information from SCEVAddRecExpr to compute the shape of the array,
so a better place for this function is in ScalarEvolution.

llvm-svn: 208456
2014-05-09 22:45:07 +00:00
Sebastian Pop
76196fee4f fix typo in debug message
llvm-svn: 208455
2014-05-09 22:45:02 +00:00
Tobias Grosser
f264562cb9 Correct formatting.
Sorry for the commit spam. My clang-format crashed on me and the vim
plugin did not print an error, but instead just left the formatting
untouched.

llvm-svn: 208358
2014-05-08 21:43:19 +00:00
Tobias Grosser
7888d0c465 Use std::remove_if to remove elements from a vector
Suggested-by: Benjamin Kramer <benny.kra@gmail.com>
llvm-svn: 208357
2014-05-08 21:32:59 +00:00
Tobias Grosser
358e9a97e7 Revert "SCEV: Use I = vector<>.erase(I) to iterate and delete at the same time"
as committed in r208282. The original commit was incorrect.

llvm-svn: 208286
2014-05-08 07:55:34 +00:00
Tobias Grosser
4c447db9fb SCEV: Use I = vector<>.erase(I) to iterate and delete at the same time
llvm-svn: 208282
2014-05-08 07:12:44 +00:00
Sebastian Pop
866eb1eecf avoid segfaulting
*Quotient and *Remainder don't have to be initialized.

llvm-svn: 208238
2014-05-07 19:00:37 +00:00
Sebastian Pop
8f355b84ae do not collect undef terms
llvm-svn: 208237
2014-05-07 19:00:32 +00:00
Sebastian Pop
d5cb815565 split delinearization pass in 3 steps
To compute the dimensions of the array in a unique way, we split the
delinearization analysis in three steps:

- find parametric terms in all memory access functions
- compute the array dimensions from the set of terms
- compute the delinearized access functions for each dimension

The first step is executed on all the memory access functions such that we
gather all the patterns in which an array is accessed. The second step reduces
all this information in a unique description of the sizes of the array. The
third step is delinearizing each memory access function following the common
description of the shape of the array computed in step 2.

This rewrite of the delinearization pass also solves a problem we had with the
previous implementation: because the previous algorithm was by induction on the
structure of the SCEV, it would not correctly recognize the shape of the array
when the memory access was not following the nesting of the loops: for example,
see polly/test/ScopInfo/multidim_only_ivs_3d_reverse.ll

; void foo(long n, long m, long o, double A[n][m][o]) {
;
;   for (long i = 0; i < n; i++)
;     for (long j = 0; j < m; j++)
;       for (long k = 0; k < o; k++)
;         A[i][k][j] = 1.0;

Starting with this patch we no longer delinearize access functions that do not
contain parameters, for example in test/Analysis/DependenceAnalysis/GCD.ll

;;  for (long int i = 0; i < 100; i++)
;;    for (long int j = 0; j < 100; j++) {
;;      A[2*i - 4*j] = i;
;;      *B++ = A[6*i + 8*j];

these accesses will not be delinearized as the upper bound of the loops are
constants, and their access functions do not contain SCEVUnknown parameters.

llvm-svn: 208232
2014-05-07 18:01:20 +00:00
Tobias Grosser
8128149f4a [C++11] Add NArySCEV->Operands iterator range
llvm-svn: 208158
2014-05-07 06:07:47 +00:00
Chandler Carruth
7b7b0c3523 [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all the header #include lines, lib/Analysis/...
edition.

This one has a bit extra as there were *other* #define's before #include
lines in addition to DEBUG_TYPE. I've sunk all of them as a block.

llvm-svn: 206843
2014-04-22 02:48:03 +00:00
Craig Topper
8cd194d4c1 [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.
llvm-svn: 206243
2014-04-15 04:59:12 +00:00
Sebastian Pop
ad1e0a2eac divide by the result of the gcd
used to fail with 'Step should divide Start with no remainder.'

llvm-svn: 205802
2014-04-08 21:21:13 +00:00
Sebastian Pop
efd7078b03 handle special cases when findGCD returns 1
used to fail with 'Step should divide Start with no remainder.'

llvm-svn: 205801
2014-04-08 21:21:10 +00:00
Sebastian Pop
2aac9574e3 in findGCD of multiply expr return the gcd
we used to return 1 instead of the gcd

llvm-svn: 205800
2014-04-08 21:21:05 +00:00
Benjamin Kramer
79c500fdd4 ScalarEvolution: Compute exit counts for loops with a power-of-2 step.
If we have a loop of the form
for (unsigned n = 0; n != (k & -32); n += 32) {}
then we know that n is always divisible by 32 and the loop must
terminate. Even if we have a condition where the loop counter will
overflow it'll always hold this invariant.

PR19183. Our loop vectorizer creates this pattern and it's also
occasionally formed by loop counters derived from pointers.

llvm-svn: 204728
2014-03-25 16:25:12 +00:00
Arnaud A. de Grandmaison
4544f80f7c Remove some dead assignements found by scan-build
llvm-svn: 204013
2014-03-15 22:13:15 +00:00
Chandler Carruth
fad39ebe19 [C++11] Add range based accessors for the Use-Def chain of a Value.
This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

llvm-svn: 203364
2014-03-09 03:16:01 +00:00
Tobias Grosser
97311619e7 Add missing parenthesis in SCEV comment
Contributed-by: Michael Zolutukin <mzolotukhin@apple.com>
llvm-svn: 202963
2014-03-05 10:37:17 +00:00
Chandler Carruth
436597fe00 [Modules] Move the ConstantRange class into the IR library. This is
a bit surprising, as the class is almost entirely abstracted away from
any particular IR, however it encodes the comparsion predicates which
mutate ranges as ICmp predicate codes. This is reasonable as they're
used for both instructions and constants. Thus, it belongs in the IR
library with instructions and constants.

llvm-svn: 202838
2014-03-04 12:24:34 +00:00
Chandler Carruth
0bf5689f06 [Modules] Move GetElementPtrTypeIterator into the IR library. As its
name might indicate, it is an iterator over the types in an instruction
in the IR.... You see where this is going.

Another step of modularizing the support library.

llvm-svn: 202815
2014-03-04 10:40:04 +00:00
Chandler Carruth
d7b36fdea7 [Modules] Move InstIterator out of the Support library, where it had no
business.

This header includes Function and BasicBlock and directly uses the
interfaces of both classes. It has to do with the IR, it even has that
in the name. =] Put it in the library it belongs to.

This is one step toward making LLVM's Support library survive a C++
modules bootstrap.

llvm-svn: 202814
2014-03-04 10:30:26 +00:00
Benjamin Kramer
e4eb1b495f [C++11] Replace llvm::next and llvm::prior with std::next and std::prev.
Remove the old functions.

llvm-svn: 202636
2014-03-02 12:27:27 +00:00
Rafael Espindola
32da4bdd4b Make DataLayout a plain object, not a pass.
Instead, have a DataLayoutPass that holds one. This will allow parts of LLVM
don't don't handle passes to also use DataLayout.

llvm-svn: 202168
2014-02-25 17:30:31 +00:00
Sebastian Pop
91ff965e4b fix a corner case in delinearization
handle special cases Step==1, Step==-1, GCD==1, and GCD==-1

llvm-svn: 201868
2014-02-21 18:15:15 +00:00
Rafael Espindola
d85e4eb0f5 Rename some member variables from TD to DL.
TargetData was renamed DataLayout back in r165242.

llvm-svn: 201581
2014-02-18 15:33:12 +00:00
Benjamin Kramer
a4e8714113 SCEV: Cast switched values to make -Wswitch more useful.
llvm-svn: 201170
2014-02-11 19:02:55 +00:00
Benjamin Kramer
e865e6358f ScalarEvolution: Analyze trip count of loops with a switch guarding the exit.
llvm-svn: 201159
2014-02-11 15:44:32 +00:00
Nick Lewycky
30a25a7139 Fix crasher introduced in r200203 and caught by a libc++ buildbot. Don't assume that getMulExpr returns a SCEVMulExpr, it may have simplified it to something else!
llvm-svn: 200210
2014-01-27 10:47:44 +00:00
Nick Lewycky
baf1d18cf0 Teach SCEV to handle more cases of 'and X, CST', specifically where CST is any number of contiguous 1 bits in a row, with any number of leading and trailing 0 bits.
Unfortunately, this in turn led to some lower quality SCEVs due to some different paths through expression simplification, so add getUDivExactExpr and use it. This fixes all instances of the problems that I found, but we can make that function smarter as necessary.

Merge test "xor-and.ll" into "and-xor.ll" since I needed to update it anyways. Test 'nsw-offset.ll' analyzes a little deeper, %n now gets a scev in terms of %no instead of a SCEVUnknown.

llvm-svn: 200203
2014-01-27 10:04:03 +00:00
Alp Toker
1c4b33e8e5 Fix known typos
Sweep the codebase for common typos. Includes some changes to visible function
names that were misspelt.

llvm-svn: 200018
2014-01-24 17:20:08 +00:00
Andrew Trick
7a9c687264 Fix PR18449: SCEV needs more precise max BECount for multi-exit loop.
llvm-svn: 199299
2014-01-15 06:42:11 +00:00
Chandler Carruth
98adff6224 [PM] Split DominatorTree into a concrete analysis result object which
can be used by both the new pass manager and the old.

This removes it from any of the virtual mess of the pass interfaces and
lets it derive cleanly from the DominatorTreeBase<> template. In turn,
tons of boilerplate interface can be nuked and it turns into a very
straightforward extension of the base DominatorTree interface.

The old analysis pass is now a simple wrapper. The names and style of
this split should match the split between CallGraph and
CallGraphWrapperPass. All of the users of DominatorTree have been
updated to match using many of the same tricks as with CallGraph. The
goal is that the common type remains the resulting DominatorTree rather
than the pass. This will make subsequent work toward the new pass
manager significantly easier.

Also in numerous places things became cleaner because I switched from
re-running the pass (!!! mid way through some other passes run!!!) to
directly recomputing the domtree.

llvm-svn: 199104
2014-01-13 13:07:17 +00:00
Chandler Carruth
ee051af6e2 [cleanup] Move the Dominators.h and Verifier.h headers into the IR
directory. These passes are already defined in the IR library, and it
doesn't make any sense to have the headers in Analysis.

Long term, I think there is going to be a much better way to divide
these matters. The dominators code should be fully separated into the
abstract graph algorithm and have that put in Support where it becomes
obvious that evn Clang's CFGBlock's can use it. Then the verifier can
manually construct dominance information from the Support-driven
interface while the Analysis library can provide a pass which both
caches, reconstructs, and supports a nice update API.

But those are very long term, and so I don't want to leave the really
confusing structure until that day arrives.

llvm-svn: 199082
2014-01-13 09:26:24 +00:00
Stepan Dyatkovskiy
3ed8a09218 Fixed old typo in ScalarEvolution, that caused wrong SCEVs zext operation.
Detailed description is here:
http://llvm.org/bugs/show_bug.cgi?id=18000#c16

For participation in bugfix process special thanks to David Wiberg.

llvm-svn: 198863
2014-01-09 12:26:12 +00:00
Chandler Carruth
53468087f3 Put the functionality for printing a value to a raw_ostream as an
operand into the Value interface just like the core print method is.
That gives a more conistent organization to the IR printing interfaces
-- they are all attached to the IR objects themselves. Also, update all
the users.

This removes the 'Writer.h' header which contained only a single function
declaration.

llvm-svn: 198836
2014-01-09 02:29:41 +00:00
Chandler Carruth
7aa902a488 Move the LLVM IR asm writer header files into the IR directory, as they
are part of the core IR library in order to support dumping and other
basic functionality.

Rename the 'Assembly' include directory to 'AsmParser' to match the
library name and the only functionality left their -- printing has been
in the core IR library for quite some time.

Update all of the #includes to match.

All of this started because I wanted to have the layering in good shape
before I started adding support for printing LLVM IR using the new pass
infrastructure, and commandline support for the new pass infrastructure.

llvm-svn: 198688
2014-01-07 12:34:26 +00:00
Benjamin Kramer
56648addca Annotate APInt methods where it's not clear whether they are in place with warn_unused_result.
Fix ScalarEvolution bugs uncovered by this.

llvm-svn: 194928
2013-11-16 16:25:41 +00:00
Sebastian Pop
2aa0f76304 add more comments around the delinearization of arrays
llvm-svn: 194612
2013-11-13 22:37:58 +00:00
Sebastian Pop
c8eb6dbd80 delinearization of arrays
llvm-svn: 194527
2013-11-12 22:47:20 +00:00
Wan Xiaofei
b1eca50fd8 Change data structure to memorize computed result in ScalarEvolution
Replace std::map with SmallVector to memorize the cached result since SCEV usually belongs to little Loop/BB
Linear scan on SmallVector is faster than std::map.

Code reviewer : Andrew Trick.
Test result   : Pass Unit Test & LLVM Test Suite

401.bzip2	0.425721	0.419981	101.37%
403.gcc		24.53855	24.2667		101.12%
429.mcf		0.060847	0.059944	101.51%
433.milc	0.646009	0.636119	101.55%
444.namd	1.383928	1.370614	100.97%
445.gobmk	5.836575	5.800225	100.63%
450.soplex	1.911257	1.895963	100.81%
456.hmmer	1.039565	1.032534	100.68%
458.sjeng	0.897401	0.885567	101.34%
464.h264ref	3.645908	3.577991	101.90%
470.lbm		0.049456	0.048398	102.19%
471.omnetpp	5.638575	5.60435		100.61%
bitmnp01	0.045738	0.045291	100.99%
cjpegv2data	0.304359	0.302833	100.50%
idctrn01	0.046433	0.045763	101.46%
quake2		4.534416	4.4952		100.87%
quake		2.688566	2.659208	101.10%
xcsoar		12.42545	12.30385	100.99%
linpack		0.038739	0.03803		101.86%
matrix01	0.053564	0.0528		101.45%
nbench		0.402867	0.395803	101.78%
tblook01	0.021265	0.021015	101.19%
ttsprk01	0.066384	0.065566	101.25%

llvm-svn: 194459
2013-11-12 09:40:41 +00:00
Andrew Trick
b072cf7882 Rewrite SCEV's backedge taken count computation.
Patch by Michele Scandale!

Rewrite of the functions used to compute the backedge taken count of a
loop on LT and GT comparisons.

I decided to split the handling of LT and GT cases becasue the trick
"a > b == -a < -b" in some cases prevents the trip count computation
due to the multiplication by -1 on the two operands of the
comparison. This issue comes from the conservative computation of
value range of SCEVs: taking the negative SCEV of an expression that
have a small positive range (e.g. [0,31]), we would have a SCEV with a
fullset as value range.

Indeed, in the new rewritten function I tried to better handle the
maximum backedge taken count computation when MAX/MIN expression are
used to handle the cases where no entry guard is found.

Some test have been modified in order to check the new value correctly
(I manually check them and reasoning on possible overflow the new
values seem correct).

I finally added a new test case related to the multiplication by -1
issue on GT comparisons.

llvm-svn: 194116
2013-11-06 02:08:26 +00:00
Benjamin Kramer
5938ec4cbe SCEV: Make the final add of an inbounds GEP nuw if we know that the index is positive.
We can't do this for the general case as saying a GEP with a negative index
doesn't have unsigned wrap isn't valid for negative indices.
  %gep = getelementptr inbounds i32* %p, i64 -1

But an inbounds GEP cannot run past the end of address space. So we check for
the very common case of a positive index and make GEPs derived from that NUW.
Together with Andy's recent non-unit stride work this lets us analyze loops
like

  void foo3(int *a, int *b) {
    for (; a < b; a++) {}
  }

PR12375, PR12376.

Differential Revision: http://llvm-reviews.chandlerc.com/D2033

llvm-svn: 193514
2013-10-28 07:30:06 +00:00
Andrew Trick
a454a863ad Clarify SCEV comments.
We handle for(i=n; i>0; i -= s) by canonicalizing within SCEV to for(i=-n; i<0; i += s).

llvm-svn: 193147
2013-10-22 05:09:40 +00:00
Matt Arsenault
fcca6dd732 Use more type helper functions
llvm-svn: 193109
2013-10-21 19:43:56 +00:00
Matt Arsenault
3089ca20bd Fix creating bitcasts between address spaces in SCEV.
The test before wasn't successfully testing this
since it was missing the datalayout piece to change
the size of the second address space.

llvm-svn: 193102
2013-10-21 18:41:10 +00:00
Matt Arsenault
5b1a8d26fc Remove unused SCEV functions
llvm-svn: 193097
2013-10-21 18:08:09 +00:00
Andrew Trick
027f71d443 SCEV should use NSW to get trip count for positive nonunit stride loops.
SCEV currently fails to compute loop counts for nonunit stride
loops. This comes up frequently. It prevents loop optimization and
forces vectorization to insert extra loop checks.

For example:
void foo(int n, int *x) {
 for (int i = 0; i < n; i += 3) {
   x[i] = i;
   x[i+1] = i+1;
   x[i+2] = i+2;
 }
}

We need to properly handle the case in which limit > INT_MAX-stride. In
the above case: n > INT_MAX-3. In this case the loop counter will step
beyond the limit and overflow at the same time. However, knowing that
signed integer overlow in undefined, we can assume the loop test
behavior is arbitrary after overflow. This obeys both C undefined
behavior rules, and the more strict LLVM poison value rules.

I'm finally fixing this in response to Hal Finkel's persistence.
The most probable reason that we never optimized this before is that
we were being careful to handle case where the developer expected a
side-effect free infinite loop relying on overflow:

for (int i = 0; i < n; i += s) {
  ++j;
}
return j;

If INT_MAX+1 is a multiple of s and n > INT_MAX-s, then we might
expect an infinite loop. However there are plenty of ways to achieve
this effect without relying on undefined behavior of signed overflow.

llvm-svn: 193015
2013-10-18 23:43:53 +00:00
Matt Arsenault
7e864bac3e Minor code simplification
llvm-svn: 191579
2013-09-27 22:38:23 +00:00
Matt Arsenault
a15663a1b4 Teach ScalarEvolution about pointer address spaces
llvm-svn: 190425
2013-09-10 19:55:24 +00:00
Andrew Trick
c14d596ae6 Fix a severe compile time problem when forming large SCEV expressions.
This fix is very lightweight. The same fix already existed for AddRec
but was missing for NAry expressions.

This is obviously an improvement and I'm unsure how to test compile
time problems.

Patch by Xiaoyi Guo!

llvm-svn: 187475
2013-07-31 02:43:40 +00:00
Shuxin Yang
e0fc600be9 Stylistic change.
Thank Nick for figuring out these problems.

llvm-svn: 186146
2013-07-12 07:25:38 +00:00
Craig Topper
74e16da8dc Use SmallVectorImpl& instead of SmallVector to avoid repeating small vector size.
llvm-svn: 186098
2013-07-11 16:22:38 +00:00
Benjamin Kramer
2880b5c20b Don't use a potentially expensive shift if all we want is one set bit.
No functionality change.

llvm-svn: 186095
2013-07-11 16:05:50 +00:00
Hal Finkel
9cb3ba300f Don't crash in SE dealing with ashr x, -1
ScalarEvolution::getSignedRange uses ComputeNumSignBits from ValueTracking on
ashr instructions. ComputeNumSignBits can return zero, but this case was not
handled correctly by the code in getSignedRange which was calling:
  APInt::getSignedMinValue(BitWidth).ashr(NS - 1)
with NS = 0, resulting in an assertion failure in APInt::ashr.

Now, we just return the conservative result (as with NS == 1).

Another bug found by llvm-stress.

llvm-svn: 185955
2013-07-09 18:16:16 +00:00
Shuxin Yang
a6173e9a56 Fix a SCEV update problem.
The symptom is seg-fault, and the root cause is that a SCEV contains a SCEVUnknown
which has null-pointer to a llvm::Value.

 This is how the problem take place:
 ===================================
  1). In the pristine input IR, there are two relevant instrutions Op1 and Op2, 
     Op1's corresponding SCEV (denoted as SCEV(op1)) is a SCEVUnknown, and
     SCEV(Op2) contains SCEV(Op1).  None of these instructions are dead.

     Op1 : V1 = ...
     ...
     Op2 : V2 = ... // directly or indirectly (data-flow) depends on Op1
    
  2) Optimizer (LSR in my case) generates an instruction holding the equivalent
     value of Op1, making Op1 dead. 
     Op1': V1' = ...
     Op1: V1 = ... ; now dead)
     Op2 : V2 = ... //Now deps on Op1', but the SCEV(Op2) still contains SCEV(Op1)

  3) Op1 is deleted, and call-back function is called to reset 
     SCEV(Op1) to indicate it is invalid. However, SCEV(Op2) is not 
     invalidated as well.

  4) Following pass get the cached, invalid SCEV(Op2), and try to manipulate it,
     and cause segfault. 

 The fix:
 ========
 It seems there is no clean yet inexpensive fix. I write to dev-list
soliciting good solution, unforunately no ack. So, I decide to fix this 
problem in a brute-force way:

  When ScalarEvolution::getSCEV is called, check if the cached SCEV 
contains a invalid SCEVUnknow, if yes, remove the cached SCEV, and
re-evaluate the SCEV from scratch.

  I compile buch of big *.c and *.cpp, fortunately, I don't see any increase
in compile time.

 Misc:
=====
 The reduced test-case has 2357 lines of code+other-stuff, too big to commit.

 rdar://14283433

llvm-svn: 185843
2013-07-08 17:33:13 +00:00
Craig Topper
9729e843cb Use SmallVectorImpl::iterator/const_iterator instead of SmallVector to avoid specifying the vector size.
llvm-svn: 185540
2013-07-03 15:07:05 +00:00
Aaron Ballman
0db8b59c69 Silencing an MSVC warning about */ being found outside of a comment.
llvm-svn: 183175
2013-06-04 01:01:56 +00:00
Andrew Trick
fafe6e2851 Prevent loop-unroll from making assumptions about undefined behavior.
Fixes rdar:14036816, PR16130.

There is an opportunity to compute precise trip counts for 'or'
expressions and multi-exit loops.
rdar:14038809: Optimize trip count computation for multi-exit loops.

To do this we need to record the fact that ExitLimit assumes NSW. When
it does not we can safely assume that the loop trip count is the
minimum ExitLimt across all subexpressions and loop exits.

llvm-svn: 183060
2013-05-31 23:34:46 +00:00
Andrew Trick
872083f8bf Fix ScalarEvolution::ComputeExitLimitFromCond for 'or' conditions.
Fixes PR16130 - clang produces incorrect code with loop/expression at -O2.

This is a 2+ year old bug that's now holding up the release. It's a
case where we knowingly made aggressive assumptions about undefined
behavior. These assumptions are wrong when SCEV is computing a
subexpression that does not directly control the branch. With this
fix, we avoid making assumptions in those cases but still optimize the
common case. SCEV's trip count computation for exits controlled by
'or' expressions is now analagous to the trip count computation for
loops with multiple exits. I had already fixed the multiple exit case
to be conservative.

llvm-svn: 182989
2013-05-31 06:43:25 +00:00
Andrew Trick
57ddfcf201 Fix SCEV forgetMemoizedResults should search and destroy backedge exprs.
Fixes PR15570: SEGV: SCEV back-edge info invalid after dead code removal.

Indvars creates a SCEV expression for the loop's back edge taken
count, then determines that the comparison is always true and
removes it.

When loop-unroll asks for the expression, it contains a NULL
SCEVUnknkown (as a CallbackVH).

forgetMemoizedResults should invalidate the loop back edges expression.

llvm-svn: 177986
2013-03-26 03:14:53 +00:00
Chandler Carruth
4c1f3c24db Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

llvm-svn: 171366
2013-01-02 11:36:10 +00:00
Chandler Carruth
a490793037 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131
2012-12-03 16:50:05 +00:00
Benjamin Kramer
0bcd999459 Follow up to 168711: It's safe to base this analysis on the found compare, just return the value for the right predicate.
Thanks to Andy for catching this.

llvm-svn: 168921
2012-11-29 19:07:57 +00:00
Andrew Trick
63817bf5f9 Improve isImpliedCond comment a bit.
llvm-svn: 168914
2012-11-29 18:35:13 +00:00
Benjamin Kramer
dd7fb68c76 SCEV: Even if the latch terminator is foldable we can't deduce the result of an unrelated condition with it.
Fixes PR14432.

llvm-svn: 168711
2012-11-27 18:16:32 +00:00