Commit Graph

17 Commits

Author SHA1 Message Date
Dan Gohman
c056454ecf Remove the Expr member from IVUsers. Instead of remembering the expression,
just ask ScalarEvolution for it on demand. This helps IVUsers be more robust
in the case of expressions changing underneath it. This fixes PR6862.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101819 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-19 21:48:58 +00:00
Dan Gohman
448db1cdef 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100699 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-07 22:27:08 +00:00
Dan Gohman
3f46a3abee Spelling fixes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97453 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-01 17:49:51 +00:00
Dan Gohman
572645cf84 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95975 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-12 10:34:29 +00:00
Bill Wendling
f7d848349e Add "dump" method to IVUsersOneStride.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95022 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-01 22:51:23 +00:00
Dan Gohman
bafbbdde38 Add a new helper function to IVUsers for returning the "canonical"
form of an expression. This is the expression without the
post-increment adjustment made, which is useful in determining
which registers will be used by the expansion.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93921 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-19 21:55:32 +00:00
Dan Gohman
6bec5bb344 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91641 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-18 00:06:20 +00:00
Evan Cheng
04149f7ffd Revert 91280-91283, 91286-91289, 91291, 91293, 91295-91296. It apparently introduced a non-deterministic behavior in the optimizer somewhere.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91598 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-17 09:39:49 +00:00
Dan Gohman
35d913e6f3 Make the IVUses member private.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91291 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-14 17:14:32 +00:00
Evan Cheng
586f69a118 - Teach LSR to avoid changing cmp iv stride if it will create an immediate that
cannot be folded into target cmp instruction.
- Avoid a phase ordering issue where early cmp optimization would prevent the
  later count-to-zero optimization.
- Add missing checks which could cause LSR to reuse stride that does not have
  users.
- Fix a bug in count-to-zero optimization code which failed to find the pre-inc
  iv's phi node.
- Remove, tighten, loosen some incorrect checks disable valid transformations.
- Quite a bit of code clean up.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86969 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-12 07:35:05 +00:00
Chris Lattner
9661c13c37 remove a few dead insertion methods.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79882 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-24 02:39:26 +00:00
Daniel Dunbar
deb052a3dd Match declaration to definition.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75440 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-12 23:50:34 +00:00
Dan Gohman
0bba49cebc Change all SCEV* to SCEV *.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74918 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-07 17:06:11 +00:00
Misha Brukman
b1d7a5d114 Use correct format for LLVM header #includes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74620 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-01 17:51:56 +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
4e8a98519e Remove the code from IVUsers that attempted to handle
casted induction variables in cases where the cast
isn't foldable. It ended up being a pessimization in
many cases. This could be fixed, but it would require
a bunch of complicated code in IVUsers' clients. The
advantages of this approach aren't visible enough to
justify it at this time.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73706 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-18 16:54:06 +00:00
Dan Gohman
81db61a2e6 Factor the code for collecting IV users out of LSR into an IVUsers class,
and generalize it so that it can be used by IndVarSimplify. Implement the
base IndVarSimplify transformation code using IVUsers. This removes
TestOrigIVForWrap and associated code, as ScalarEvolution now has enough
builtin overflow detection and folding logic to handle all the same cases,
and more. Run "opt -iv-users -analyze -disable-output" on your favorite
loop for an example of what IVUsers does.

This lets IndVarSimplify eliminate IV casts and compute trip counts in
more cases. Also, this happens to finally fix the remaining testcases
in PR1301.

Now that IndVarSimplify is being more aggressive, it occasionally runs
into the problem where ScalarEvolutionExpander's code for avoiding
duplicate expansions makes it difficult to ensure that all expanded
instructions dominate all the instructions that will use them. As a
temporary measure, IndVarSimplify now uses a FixUsesBeforeDefs function
to fix up instructions inserted by SCEVExpander. Fortunately, this code
is contained, and can be easily removed once a more comprehensive
solution is available.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71535 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-12 02:17:14 +00:00