Commit Graph

697 Commits

Author SHA1 Message Date
Nick Lewycky
3846163aee Now that we look at all the header PHIs, we need to consider all the header PHIs
when deciding that the loop has stopped evolving. Fixes miscompile in the gcc
torture testsuite!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142843 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 21:02:38 +00:00
Nick Lewycky
7c3fc57472 Reapply r142781 with fix. Original message:
Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
  loop header when computing the trip count.

  With this, we now constant evaluate:
    struct ListNode { const struct ListNode *next; int i; };
    static const struct ListNode node1 = {0, 1};
    static const struct ListNode node2 = {&node1, 2};
    static const struct ListNode node3 = {&node2, 3};
    int test() {
      int sum = 0;
      for (const struct ListNode *n = &node3; n != 0; n = n->next)
        sum += n->i;
      return sum;
    }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142790 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 06:57:05 +00:00
Nick Lewycky
5bef0eb1de PHI nodes not in the loop header aren't part of the loop iteration initial
state. Furthermore, they might not have two operands. This fixes the underlying
issue behind the crashes introduced in r142781.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142788 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 05:51:01 +00:00
Nick Lewycky
38af3d5a8d Speculatively revert r142781. Bots are showing
Assertion `i_nocapture < OperandTraits<PHINode>::operands(this) && "getOperand() out of range!"' failed.
coming out of indvars.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142786 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-24 04:00:25 +00:00
Nick Lewycky
795cb48f1a Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
loop header when computing the trip count.

With this, we now constant evaluate:
  struct ListNode { const struct ListNode *next; int i; };
  static const struct ListNode node1 = {0, 1};
  static const struct ListNode node2 = {&node1, 2};
  static const struct ListNode node3 = {&node2, 3};
  int test() {
    int sum = 0;
    for (const struct ListNode *n = &node3; n != 0; n = n->next)
      sum += n->i;
    return sum;
  }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142781 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-23 23:43:14 +00:00
Nick Lewycky
614fef6d5a Make SCEV's brute force analysis stronger in two ways. Firstly, we should be
able to constant fold load instructions where the argument is a constant.
Second, we should be able to watch multiple PHI nodes through the loop; this
patch only supports PHIs in loop headers, more can be done here.

With this patch, we now constant evaluate:
  static const int arr[] = {1, 2, 3, 4, 5};
  int test() {
    int sum = 0;
    for (int i = 0; i < 5; ++i) sum += arr[i];
    return sum;
  }


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142731 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-22 19:58:20 +00:00
Nick Lewycky
4c7f1caadc An instruction's operands aren't necessarily instructions or constants. They
could be arguments, for example.

No testcase because this is a bug-fix broken out of a larger optimization patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141951 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-14 09:38:46 +00:00
Andrew Trick
ef8a4c2a65 Fixes PR11070 - assert in SCEV getConstantEvolvingPHIOperands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141219 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 22:06:53 +00:00
Andrew Trick
b73a8414a7 Typo. Thanks Bob.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141188 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 16:52:28 +00:00
Chandler Carruth
f3baa581e8 Fix a broken assert found by -Wparentheses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141168 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 07:02:23 +00:00
Andrew Trick
28ab7db2c3 Fix disabled SCEV analysis caused r141161 and add unit test.
I noticed during self-review that my previous checkin disabled some
analysis. Even with the reenabled analysis the test case runs in about
5ms. Without the fix, it will take several minutes at least.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141164 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 05:58:49 +00:00
Andrew Trick
13d31e0368 Avoid exponential recursion in SCEV getConstantEvolvingPHI and EvaluateExpression.
Note to compiler writers: never recurse on multiple instruction
operands without memoization.
Fixes rdar://10187945. Was taking 45s, now taking 5ms.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141161 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 03:25:31 +00:00
Nick Lewycky
e97728ecf8 The product of two chrec's can always be represented as a chrec.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141066 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-04 06:51:26 +00:00
Nick Lewycky
1cbae18cf6 Reapply r140979 with fix! We never did get a testcase, but careful review of the
logic by David Meyer revealed this bug.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140992 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-03 07:10:45 +00:00
Nick Lewycky
4fcc80a486 Revert r140979 due to reports of bootstrap failure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140980 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-03 05:14:59 +00:00
Nick Lewycky
8fde4f5842 Add one more case we compute a max trip count.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140979 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-03 01:03:57 +00:00
Andrew Trick
f63ae2159d indvars: generalize SCEV getPreStartForSignExtend.
Handle general Add expressions to avoid leaving around redundant
32-bit IVs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140701 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-28 17:02:54 +00:00
Andrew Trick
543376743c Set NSW/NUW flags on SCEVAddExpr when the operation is flagged as
such.

I'm doing this now for completeness because I can't think of/remember
any reason that it was left out. I'm not sure it will help anything,
but if we don't do it we need to explain why in comments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139450 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-10 01:09:50 +00:00
Nick Lewycky
c103a08a11 This transform only handles two-operand AddRec's. Prevent it from trying to
handle anything more complex. Fixes PR10383 again!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139186 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 21:42:18 +00:00
Nick Lewycky
ecd37bcd5c Fix typo in comment again.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139139 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 07:02:40 +00:00
Nick Lewycky
9115fba853 Apparently we compile the code, not the comments. Thanks Eli!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139138 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 06:56:00 +00:00
Nick Lewycky
e6180992eb Fix typo in comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139137 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 06:46:01 +00:00
Nick Lewycky
8cfb2f8bce Nope! I had it right the first time. Revert the operative part of r139135 and
add more showing of my work.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139136 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 06:39:54 +00:00
Nick Lewycky
28682ae00f Fix flipped sign. While there, show my math.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139135 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 05:33:18 +00:00
Nick Lewycky
980e9f399d No no no, fix typo properly!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139134 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 05:08:09 +00:00
Nick Lewycky
fa151a79ed The logic inside getMulExpr to simplify {a,+,b}*{c,+,d} was wrong, which was
visible given a=b=c=d=1, on iteration #1 (the second iteration). Replace it with
correct math. Fixes PR10383!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139133 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 05:05:14 +00:00
Nick Lewycky
b2840fdcd8 Revert r139126 due to selfhost failures reported by buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139130 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06 02:43:13 +00:00
Nick Lewycky
77b7352db0 Teach SCEV to report a max backedge count in one interesting case in
HowFarToZero; the case for a canonical loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139126 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-05 23:25:16 +00:00
Andrew Trick
252ef7a61a Comment and clarifying assert.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139036 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-02 21:20:46 +00:00
Andrew Trick
b1831c6640 Allow loop unrolling to get known trip counts from ScalarEvolution.
SCEV unrolling can unroll loops with arbitrary induction variables. It
is a prerequisite for -disable-iv-rewrite performance. It is also
easily handles loops of arbitrary structure including multiple exits
and is generally more robust.

This is under a temporary option to avoid affecting default
behavior for the next couple of weeks. It is needed so that I can
checkin unit tests for updateUnloop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137384 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-11 23:36:16 +00:00
Andrew Trick
06988bcf6a Made SCEV's UDiv expressions more canonical. When dividing a
recurrence, the initial values low bits can sometimes be ignored.

To take advantage of this, added FoldIVUser to IndVarSimplify to fold
an IV operand into a udiv/lshr if the operator doesn't affect the
result.

-indvars -disable-iv-rewrite now transforms

i = phi i4
i1 = i0 + 1
idx = i1 >> (2 or more)
i4 = i + 4

into

i = phi i4
idx = i0 >> ...
i4 = i + 4


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137013 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-06 07:00:37 +00:00
Andrew Trick
fcb4356dee Use consistent terminology for loop exit/exiting blocks. Name change only.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136677 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 04:23:35 +00:00
Andrew Trick
5116ff671f 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136100 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-26 17:19:55 +00:00
Jay Foad
1d2f569c34 Use ArrayRef in ConstantFoldInstOperands and ConstantFoldCall.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135477 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-19 13:32:40 +00:00
Chris Lattner
db125cfaf5 land David Blaikie's patch to de-constify Type, with a few tweaks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135375 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18 04:54:35 +00:00
Andrew Trick
cf31f91931 SCEV: missing null check fix for r132360, dragonegg crash.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132416 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-01 19:14:56 +00:00
Andrew Trick
b1ce4c09dd scev: Better sign-extend removal. Normalize postincrement recurrences
so that their sign extended forms are congruent when no overflow occurs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132360 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-31 21:17:47 +00:00
Dan Gohman
77a2c4c1e5 Change a few std::maps to DenseMaps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131088 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-09 18:44:09 +00:00
Andrew Trick
a2a162077c Corrects an old, old typo in a case that doesn't seem to be reached in practice.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130316 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-27 18:17:36 +00:00
Andrew Trick
104f4adeac Test case and comment for PR9633.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130294 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-27 05:42:17 +00:00
Andrew Trick
3f95c88162 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130271 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-27 01:21:25 +00:00
Dan Gohman
308bec390f Fix an iterator invalidation bug.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130166 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-25 22:48:29 +00:00
Chris Lattner
7a2bdde0a0 Fix a ton of comment typos found by codespell. Patch by
Luis Felipe Strano Moraes!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129558 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-15 05:18:47 +00:00
Andrew Trick
b12a754cce 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127839 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-17 23:51:11 +00:00
Andrew Trick
4dbe200b2d Remove getMinusSCEVForExitTest().
This function performed acrobatics to prove no-self-wrap, which we now
have for free.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127643 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-15 01:16:14 +00:00
Andrew Trick
c343c1e27e Propagate SCEV no-wrap flags whenever possible.
This needs review.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127638 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-15 00:37:00 +00:00
Andrew Trick
a053b21177 Negating a recurrence preserves no-self-wrap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127593 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-14 17:38:54 +00:00
Andrew Trick
dcfd404e3c HowFarToZero can compute a trip count as long as the recurrence has no-self-wrap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127591 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-14 17:28:02 +00:00
Andrew Trick
3228cc259b 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127590 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-14 16:50:06 +00:00
Andrew Trick
e62289b98f 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127342 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09 17:29:58 +00:00
Andrew Trick
635f71880b whitespace
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127340 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09 17:23:39 +00:00
Chris Lattner
8ebaf90958 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125449 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 03:14:49 +00:00
Chris Lattner
1021236c74 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125410 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-11 21:43:33 +00:00
Nick Lewycky
e19b7b80bd 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!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124282 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-26 08:40:22 +00:00
Dan Gohman
a3bbf2411f Add a comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124126 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-24 17:54:18 +00:00
Nick Lewycky
76167af9b1 Simplify some code with no functionality change. Make the test a lot more
robust against smarter optimizations, using the power of FileCheck.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124081 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-23 20:06:05 +00:00
Nick Lewycky
630d85a78c Use value ranges to fold ext(trunc) in SCEV when possible.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124062 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-23 06:20:19 +00:00
Nick Lewycky
9b8d2c26bc Have SCEV turn sext(x) into zext(x) when x is s>= 0. This applies many times in
"make check" alone.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124046 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-22 22:06:21 +00:00
Nick Lewycky
5c6fc1cab7 Similarly, analyze truncate through multiply.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123842 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-19 18:56:00 +00:00
Nick Lewycky
30aa8b13c9 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123838 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-19 16:59:46 +00:00
Nick Lewycky
73f565e754 Add a missing SCEV simplification sext(zext x) --> zext x.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123832 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-19 15:56:12 +00:00
Chris Lattner
6038a6351e some comment improvements.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123243 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 17:11:59 +00:00
Eric Christopher
87376839a6 Temporarily revert 123133, it's causing some regressions and I'm trying
to get a testcase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123225 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 09:02:09 +00:00
Chris Lattner
9651870815 the GEP faq says that only inbounds geps are guaranteed to not overflow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123218 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 06:44:41 +00:00
Chris Lattner
bd9d53cc65 add a fixme: ir isn't expressive enough.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123139 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 23:02:10 +00:00
Chris Lattner
53e1d45adb 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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123138 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 22:58:47 +00:00
Chris Lattner
7975e3ebba rearrange some code, no functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123136 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 22:39:48 +00:00
Chris Lattner
ad19c8c63c 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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123133 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 22:31:26 +00:00
Chris Lattner
992efb0378 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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123131 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 22:26:35 +00:00
Chris Lattner
6d5a2411aa 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123105 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 02:28:48 +00:00
Chris Lattner
f1859891b7 reduce indentation. Print <nuw> and <nsw> when dumping SCEV AddRec's
that have the bit set.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123104 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 02:16:18 +00:00
Jay Foad
40f8f6264d 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121120 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-07 08:25:19 +00:00
Jay Foad
7a874ddda0 PR5207: Rename overloaded APInt methods set(), clear(), flip() to
setAllBits(), setBit(unsigned), etc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120564 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-01 08:53:58 +00:00
Benjamin Kramer
f601d6df6f Simplify code. No change in functionality.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119908 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-20 18:43:35 +00:00
Benjamin Kramer
b458b15510 Silence warning about an uninitialized variable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119800 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-19 11:37:26 +00:00
Duncan Sands
d0c6f3dafd 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119727 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-18 19:59:41 +00:00
Dan Gohman
9c9fcfc719 Introduce memoization for ScalarEvolution dominates and properlyDominates
queries, and SCEVExpander getRelevantLoop queries.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119595 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-18 00:34:22 +00:00
Dan Gohman
56a7568218 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119587 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 23:28:48 +00:00
Dan Gohman
714b5290b0 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119584 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 23:21:44 +00:00
Dan Gohman
4ce32db913 Make SCEV::getType() and SCEV::print non-virtual. Move SCEV::hasOperand
to ScalarEvolution. Delete SCEV::~SCEV. SCEV is no longer virtual.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119578 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 22:27:42 +00:00
Dan Gohman
dc0e8fb9f9 Move SCEV::dominates and properlyDominates to ScalarEvolution.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119570 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 21:41:58 +00:00
Dan Gohman
17ead4ff4b Move SCEV::isLoopInvariant and hasComputableLoopEvolution to be member
functions of ScalarEvolution, in preparation for memoization and
other optimizations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119562 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 21:23:15 +00:00
Duncan Sands
6f8a5ddcd8 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119556 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 20:49:12 +00:00
Dan Gohman
203a7239ae Verify SCEVAddRecExpr's invariant in ScalarEvolution::getAddRecExpr
instead of in SCEVAddRecExpr's constructor, in preparation for an
upcoming change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119554 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 20:48:38 +00:00
Dan Gohman
7c0fd8eb72 Fix ScalarEvolution's range memoization to avoid using a
default ctor with ConstantRange.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119550 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 20:23:08 +00:00
Duncan Sands
a0c5244e85 Have ScalarEvolution use SimplifyInstruction rather than hasConstantValue.
While there, add a note about an inefficiency I noticed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119458 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 04:18:45 +00:00
Dan Gohman
6678e7b6eb Memoize results from ScalarEvolution's getUnsignedRange and getSignedRange.
This fixes some extreme compile times on unrolled sha512 code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119455 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 02:44:44 +00:00
Dan Gohman
e60dcb5e97 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117698 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 20:16:10 +00:00
Owen Anderson
081c34b725 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116820 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-19 17:21:58 +00:00
Owen Anderson
2ab36d3502 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116334 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-12 19:48:12 +00:00
Owen Anderson
ce665bd2e2 Now with fewer extraneous semicolons!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115996 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 22:25:06 +00:00
Dan Gohman
7a391832f4 Don't add the operand count to SCEV uniquing data; FoldingSetNodeID
already knows its own length, so this is redundant.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115521 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-04 17:24:08 +00:00
Dan Gohman
3f19c091bf Reapply r112432, now that the real problem is addressed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112667 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-31 22:53:17 +00:00
Dan Gohman
6a0c125ed5 Reapply r112433, now that the real problem is addressed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112666 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-31 22:52:12 +00:00
Dan Gohman
90b5f25e8d Revert r110916. This patch is buggy because the code inside the
inner loop doesn't update all the variables in the outer loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112665 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-31 22:50:31 +00:00
Dan Gohman
26125c65b9 Revert r112432. It appears to be exposing a problem in the emacs build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112638 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-31 20:58:44 +00:00
Dan Gohman
f3bba4c1ae Speculatively revert r112433.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112608 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-31 17:56:47 +00:00
Dan Gohman
d578a40853 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112433 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-29 15:16:58 +00:00
Dan Gohman
b8fc62bc58 Batch up subtracts along with adds, when analyzing long chains of
operations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112432 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-29 15:10:06 +00:00
Dan Gohman
c6a8e99fb3 Micro-optimize GroupByComplexity.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112431 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-29 15:07:13 +00:00