409 Commits

Author SHA1 Message Date
Dan Gohman
607e02b33a When determining a canonical insert position, don't climb deeper
into adjacent loops. Also, ensure that the insert position is
dominated by the loop latch of any loop in the post-inc set which
has a latch.

llvm-svn: 100906
2010-04-09 22:07:05 +00:00
Dan Gohman
42ec4eb351 When looking for loop-invariant users, look through no-op instructions,
so that an unfortunately placed bitcast doesn't pin a value in a
register.

llvm-svn: 100883
2010-04-09 19:12:34 +00:00
Dan Gohman
d2df643ddb Refactor the code for computing the insertion point for an expression into
a separate function.

llvm-svn: 100845
2010-04-09 02:00:38 +00:00
Dan Gohman
9b5d0bb774 Avoid allocating a value of zero in a register if the initial formula
inputs happen to negate each other.

llvm-svn: 100828
2010-04-08 23:36:27 +00:00
Dan Gohman
4ce1fb1448 Add variants of ult, ule, etc. which take a uint64_t RHS, for convenience.
llvm-svn: 100824
2010-04-08 23:03:40 +00:00
Dan Gohman
4506539d84 When expanding expressions which are using post-inc mode for multiple loops,
ensure that the expansion is dominated by the increments of those loops.

llvm-svn: 100748
2010-04-08 05:57:57 +00:00
Dan Gohman
d006ab90dd Generalize IVUsers to track arbitrary expressions rather than expressions
explicitly split into stride-and-offset pairs. Also, add the
ability to track multiple post-increment loops on the same expression.

This refines the concept of "normalizing" SCEV expressions used for
to post-increment uses, and introduces a dedicated utility routine for
normalizing and denormalizing expressions.

This fixes the expansion of expressions which are post-increment users
of more than one loop at a time. More broadly, this takes LSR another
step closer to being able to reason about more than one loop at a time.

llvm-svn: 100699
2010-04-07 22:27:08 +00:00
Dan Gohman
d42e09d91e Ignore debug intrinsics in yet more places.
llvm-svn: 99580
2010-03-26 00:33:27 +00:00
Gabor Greif
c78d720f02 rename use_const_iterator to const_use_iterator for consistency's sake
llvm-svn: 99564
2010-03-25 23:06:16 +00:00
Dan Gohman
29707de4fe Make SCEVExpander and LSR more aggressive about hoisting expressions out
of loops.

llvm-svn: 97642
2010-03-03 05:29:13 +00:00
Dan Gohman
52f5563973 Non-affine post-inc SCEV expansions have more code which must be
emitted after the increment. Make sure the insert position
reflects this. This fixes PR6453.

llvm-svn: 97537
2010-03-02 01:59:21 +00:00
Dan Gohman
8b0a419eb1 Spelling fixes.
llvm-svn: 97453
2010-03-01 17:49:51 +00:00
Dan Gohman
8c16b38262 Remove unused variables and parameters.
llvm-svn: 96780
2010-02-22 04:11:59 +00:00
Dan Gohman
4506fcb3c2 When emitting an instruction which depends on both a post-incremented
induction variable value and a loop-variant value, don't force the
insert position to be at the post-increment position, because it may
not be dominated by the loop-variant value. This fixes a
use-before-def problem noticed on PPC.

llvm-svn: 96774
2010-02-22 03:59:54 +00:00
Dan Gohman
4eebb94094 Rename getSDiv to getExactSDiv to reflect its behavior in cases where
the division would have a remainder.

llvm-svn: 96693
2010-02-19 19:35:48 +00:00
Dan Gohman
85af256779 Check for overflow when scaling up an add or an addrec for
scaled reuse.

llvm-svn: 96692
2010-02-19 19:32:49 +00:00
Dan Gohman
2446f57503 When determining the set of interesting reuse factors, consider
strides in foreign loops. This helps locate reuse opportunities
with existing induction variables in foreign loops and reduces
the need for inserting new ones. This fixes rdar://7657764.

llvm-svn: 96629
2010-02-19 00:05:23 +00:00
Dan Gohman
13ac3b2139 Delete some unneeded casts.
llvm-svn: 96429
2010-02-17 00:42:19 +00:00
Dan Gohman
5f10d6c52c Don't attempt to divide INT_MIN by -1; consider such cases to
have overflowed.

llvm-svn: 96428
2010-02-17 00:41:53 +00:00
Dan Gohman
6deab96c81 Refactor rewriting for PHI nodes into a separate function.
llvm-svn: 96382
2010-02-16 20:25:07 +00:00
Dan Gohman
0849ed5e26 Fix whitespace.
llvm-svn: 96372
2010-02-16 19:42:34 +00:00
Duncan Sands
19d0b47b1f There are two ways of checking for a given type, for example isa<PointerType>(T)
and T->isPointerTy().  Convert most instances of the first form to the second form.
Requested by Chris.

llvm-svn: 96344
2010-02-16 11:11:14 +00:00
Dan Gohman
521efe68ab Split the main for-each-use loop again, this time for GenerateTruncates,
as it also peeks at which registers are being used by other uses. This
makes LSR less sensitive to use-list order.

llvm-svn: 96308
2010-02-16 01:42:53 +00:00
Dan Gohman
e4e51a63da Fix whitespace.
llvm-svn: 96179
2010-02-14 18:51:39 +00:00
Dan Gohman
e7f74bb16c Fix a comment.
llvm-svn: 96178
2010-02-14 18:51:20 +00:00
Dan Gohman
bb7d52213c When complicated expressions are broken down into subexpressions
with multiplication by constants distributed through, occasionally
those subexpressions can include both x and -x. For now, if this
condition is discovered within LSR, just prune such cases away,
as they won't be profitable. This fixes a "zero allocated in a
base register" assertion failure.

llvm-svn: 96177
2010-02-14 18:50:49 +00:00
Dan Gohman
2d0f96d49a Actually, this code doesn't have to be quite so conservative in
the no-TLI case. But it should still default to declining the
transformation.

llvm-svn: 96152
2010-02-14 03:21:49 +00:00
Dan Gohman
cb76a806f0 Don't attempt aggressive post-inc uses if TargetLowering is not available,
because profitability can't be sufficiently approximated.

llvm-svn: 96148
2010-02-14 02:45:21 +00:00
John McCall
0daaf13b97 Make LSR not crash if invoked without target lowering info, e.g. if invoked
from opt.

llvm-svn: 96135
2010-02-13 23:40:16 +00:00
Dan Gohman
5b18f039eb Fix a pruning heuristic which implicitly assumed that SmallPtrSet is
deterministically sorted.

llvm-svn: 96071
2010-02-13 02:06:02 +00:00
Dan Gohman
2b75de97c0 Reapply 95979, a compile-time speedup, now that the bug it exposed is fixed.
llvm-svn: 96005
2010-02-12 19:35:25 +00:00
Dan Gohman
363f847ec6 Fix this code to avoid dereferencing an end() iterator in
offset distributions it doesn't expect.

llvm-svn: 96002
2010-02-12 19:20:37 +00:00
Daniel Dunbar
e0b2c69d3c Revert "Reverse the order for collecting the parts of an addrec. The order", it
is breaking llvm-gcc bootstrap.

llvm-svn: 95988
2010-02-12 17:27:08 +00:00
Dan Gohman
0194f58047 Reverse the order for collecting the parts of an addrec. The order
doesn't matter, except that ScalarEvolution tends to need less time
to fold the results this way.

llvm-svn: 95979
2010-02-12 11:08:26 +00:00
Dan Gohman
45774ce0ad Reapply the new LoopStrengthReduction code, with compile time and
bug fixes, and with improved heuristics for analyzing foreign-loop
addrecs.

This change also flattens IVUsers, eliminating the stride-oriented
groupings, which makes it easier to work with.

llvm-svn: 95975
2010-02-12 10:34:29 +00:00
Bill Wendling
48816a0b3f Generic reformatting and comment fixing. No functionality change.
llvm-svn: 94771
2010-01-29 00:52:43 +00:00
Bill Wendling
8277838cf8 Add newline to debugging output, and fix some grammar-os in comment.
llvm-svn: 94765
2010-01-29 00:27:39 +00:00
Dan Gohman
045f81981a Revert LoopStrengthReduce.cpp to pre-r94061 for now.
llvm-svn: 94123
2010-01-22 00:46:49 +00:00
Dan Gohman
b1ee154b6b When inserting expressions for post-increment users which contain
loop-variant components, adds must be inserted after the increment.
Keep track of the increment position for this case, and insert
these adds in the correct location.

llvm-svn: 94110
2010-01-21 23:01:22 +00:00
Dan Gohman
cb8d577eb2 Include IVUsers information in LSR's debug output.
llvm-svn: 94108
2010-01-21 22:46:32 +00:00
Dan Gohman
29916e023d Prune the search for candidate formulae if the number of register
operands exceeds the number of registers used in the initial
solution, as that wouldn't lead to a profitable solution anyway.

llvm-svn: 94107
2010-01-21 22:42:49 +00:00
Dan Gohman
c903499ff8 Add a comment.
llvm-svn: 94104
2010-01-21 21:31:09 +00:00
Dan Gohman
51ad99d2c5 Re-implement the main strength-reduction portion of LoopStrengthReduction.
This new version is much more aggressive about doing "full" reduction in
cases where it reduces register pressure, and also more aggressive about
rewriting induction variables to count down (or up) to zero when doing so
reduces register pressure.

It currently uses fairly simplistic algorithms for finding reuse
opportunities, but it introduces a new framework allows it to combine
multiple strategies at once to form hybrid solutions, instead of doing
all full-reduction or all base+index.

llvm-svn: 94061
2010-01-21 02:09:26 +00:00
Dan Gohman
b5358003fb Set Changed properly after calling DeleteDeadPHIs.
llvm-svn: 92735
2010-01-05 16:31:45 +00:00
David Greene
2330f78075 Remove dump routine and the associated Debug.h from a header. Patch up
other files to compensate.

llvm-svn: 92075
2009-12-23 22:58:38 +00:00
Dan Gohman
18fa5686f6 Add Loop contains utility methods for testing whether a loop
contains another loop, or an instruction. The loop form is
substantially more efficient on large loops than the typical
code it replaces.

llvm-svn: 91654
2009-12-18 01:24:09 +00:00
Dan Gohman
fd7231f1fe Minor code simplification.
llvm-svn: 91653
2009-12-18 01:20:44 +00:00
Dan Gohman
b1924e8a0f Don't pass const pointers by reference.
llvm-svn: 91647
2009-12-18 00:38:08 +00:00
Dan Gohman
92c3696524 Reapply LoopStrengthReduce and IVUsers cleanups, excluding the part
of 91296 that caused trouble -- the Processed list needs to be
preserved for the livetime of the pass, as AddUsersIfInteresting
is called from other passes.

llvm-svn: 91641
2009-12-18 00:06:20 +00:00
Evan Cheng
090ac0865a Revert 91280-91283, 91286-91289, 91291, 91293, 91295-91296. It apparently introduced a non-deterministic behavior in the optimizer somewhere.
llvm-svn: 91598
2009-12-17 09:39:49 +00:00