Commit Graph

133 Commits

Author SHA1 Message Date
Dan Gohman 7227bc88f0 When printing a SCEVUnknown with pointer type, don't print an
artificial "ptrtoint", as it tends to clutter up complicated
expressions. The cast operators now print both source and
destination types, which is usually sufficient.

llvm-svn: 70554
2009-05-01 17:02:22 +00:00
Dan Gohman 2b8da35f9d Extend ScalarEvolution's getBackedgeTakenCount to be able to
compute an upper-bound value for the trip count, in addition to
the actual trip count. Use this to allow getZeroExtendExpr and
getSignExtendExpr to fold casts in more cases.

This may eventually morph into a more general value-range
analysis capability; there are certainly plenty of places where
more complete value-range information would allow more folding.

llvm-svn: 70509
2009-04-30 20:47:05 +00:00
Dan Gohman 494dac3f84 Generalize the cast-of-addrec folding to handle folding of SCEVs like
(sext i8 {-128,+,1} to i64) to i64 {-128,+,1}, where the iteration
crosses from negative to positive, but is still safe if the trip
count is within range.

llvm-svn: 70421
2009-04-29 22:28:28 +00:00
Dan Gohman d9775a3be1 Fix this test to match the new output from scalar-evolution.
llvm-svn: 70410
2009-04-29 21:06:20 +00:00
Dan Gohman d9b11b2ef4 Include the source type in SCEV cast expression debug output, and
print sext, zext, and trunc, instead of signextend, zeroextend,
and truncate, respectively, for consistency with the main IR.

llvm-svn: 70405
2009-04-29 20:27:52 +00:00
Dan Gohman 807dff7486 Fix a grammaro in a comment.
llvm-svn: 70331
2009-04-28 21:54:23 +00:00
Nick Lewycky b4d9f7a9b3 Simplify trunc(extend(x)) in SCEVs, just for completeness. Also fix some odd
whitespace in the same file.

llvm-svn: 69870
2009-04-23 05:15:08 +00:00
Owen Anderson 7d82244be7 Testcase for PR3909.
llvm-svn: 69868
2009-04-23 04:33:42 +00:00
Dan Gohman e14efcc9f4 When turning (ashr(shl(x, n), n)) into sext(trunc(x)), the width of the
type to truncate to should be the number of bits of the value that are
preserved, not the number that are clobbered with sign-extension.
This fixes regressions in ldecod.

llvm-svn: 69704
2009-04-21 20:18:36 +00:00
Chris Lattner d35d43dde8 change this to test for an alias result more directly.
llvm-svn: 67046
2009-03-16 18:28:27 +00:00
Nick Lewycky 8e0f9ac051 Add a replacement for 2009-02-12-GEPNoalias.ll that works without -debug.
llvm-svn: 67011
2009-03-14 19:40:09 +00:00
Chris Lattner a18c768e6d remove a buggy test, it is not ok to use -debug in RUN line.
llvm-svn: 66918
2009-03-13 18:19:34 +00:00
Dan Gohman b4e896baed Update this test for the LoopInfo::print changes.
llvm-svn: 65597
2009-02-27 00:17:49 +00:00
Dan Gohman 0bddac16a8 Rename ScalarEvolution's getIterationCount to getBackedgeTakenCount,
to more accurately describe what it does. Expand its doxygen comment
to describe what the backedge-taken count is and how it differs
from the actual iteration count of the loop. Adjust names and
comments in associated code accordingly.

llvm-svn: 65382
2009-02-24 18:55:53 +00:00
Nick Lewycky c60bd012bc BasicAA was making the assumption that a local allocation which hadn't escaped
couldn't ever be the return of call instruction. However, it's quite possible
that said local allocation is itself the return of a function call. That's
what malloc and calloc are for, actually.

llvm-svn: 64442
2009-02-13 07:06:27 +00:00
Owen Anderson 1caf7fef8e Finish making AliasAnalysis aware of the fact that most atomic intrinsics only dereference their arguments, and enhance
BasicAA to make use of this fact when computing ModRef info.

llvm-svn: 63718
2009-02-04 05:16:46 +00:00
Nick Lewycky 52348300a4 Wind SCEV back in time, to Nov 18th. This 'fixes' PR3275, PR3294, PR3295,
PR3296 and PR3302.

llvm-svn: 62160
2009-01-13 09:18:58 +00:00
Nick Lewycky 380292a51a Don't try to analyze this "backward" case. This is overly conservative
pending a correct solution.

llvm-svn: 61589
2009-01-02 18:54:17 +00:00
Nick Lewycky d80ff135b5 Check that the function prototypes are correct before assuming that the
parameters are pointers.

llvm-svn: 61451
2008-12-27 16:20:53 +00:00
Nick Lewycky 2abb108f1b Resubmit support for the 'nocapture' attribute.
The problematic part of this patch is that we were out of attribute bits,
requiring some fancy bit hacking to make it fit (by shrinking alignment)
without breaking existing users or the file format.

This change will require users to rebuild llvm-gcc to match llvm.

llvm-svn: 61239
2008-12-19 06:39:12 +00:00
Bill Wendling e38c7400c9 Remove empty test.
llvm-svn: 61095
2008-12-16 19:07:17 +00:00
Bill Wendling a397baea88 Temporarily revert r61019, r61030, and r61040. These were breaking LLVM Release
builds.

llvm-svn: 61094
2008-12-16 19:06:48 +00:00
Nick Lewycky 69c9aa4ce5 Generalize support for analyzing loops to include SLE/SGE loop exit conditions
and support for non-unit strides with signed exit conditions.

llvm-svn: 61082
2008-12-16 08:30:01 +00:00
Chris Lattner e3401db1f3 Teach basicaa to use the nocapture attribute when possible. When the
intrinsics are properly marked nocapture, the fixme should be addressed.

llvm-svn: 61040
2008-12-15 18:59:22 +00:00
Nick Lewycky 729bf137a8 Revert my re-instated reverted commit, fixes the bootstrap build on x86-64 linux.
llvm-svn: 60951
2008-12-12 17:09:07 +00:00
Nick Lewycky 6a344e097c Sneaky, sneaky: move the -1 to the outside of the SMax. Reinstate the
optimization of SGE/SLE with unit stride, now that it works properly.

llvm-svn: 60881
2008-12-11 17:40:14 +00:00
Chris Lattner 2e84a548d6 Allow basicaa to walk through geps with identical indices in
parallel, allowing it to decide that P/Q must alias if A/B
must alias in things like:
 P = gep A, 0, i, 1
 Q = gep B, 0, i, 1

This allows GVN to delete 62 more instructions out of 403.gcc.

llvm-svn: 60820
2008-12-10 01:04:47 +00:00
Evan Cheng 058522f1da xfail this for now.
llvm-svn: 60777
2008-12-09 18:43:00 +00:00
Nick Lewycky f545749f2b It's easy to handle SLE/SGE when the loop has a unit stride.
llvm-svn: 60748
2008-12-09 07:25:04 +00:00
Nick Lewycky f5ffcbcd0b Extend the 'noalias' attribute to function return values. This is intended to
indicate functions that allocate, such as operator new, or list::insert. The
actual definition is slightly less strict (for now).

No changes to the bitcode reader/writer, asm printer or verifier were needed.

llvm-svn: 59934
2008-11-24 03:41:24 +00:00
Nick Lewycky 1c451ae43e Add a utility function that detects whether a loop is guaranteed to be finite.
Use it to safely handle less-than-or-equals-to exit conditions in loops. These
also occur when the loop exit branch is exit on true because SCEV inverses the
icmp predicate.

Use it again to handle non-zero strides, but only with an unsigned comparison
in the exit condition.

llvm-svn: 59528
2008-11-18 15:10:54 +00:00
Nick Lewycky 625c6f79b2 Don't brute-force analyze cubic or higher polynomials.
If this patch causes a performance regression for anyone, please let me know,
and it can be fixed in a different way with much more effort.

llvm-svn: 59384
2008-11-16 04:14:25 +00:00
Nick Lewycky 7b14e20a5e Don't crash analyzing certain quadratics (addrec of {X,+,Y,+,1}).
We're still waiting on code that actually analyzes them properly.

llvm-svn: 58592
2008-11-03 02:43:49 +00:00
Duncan Sands 9c40c28926 Rationalize the names of passes that print information:
-callgraph => print-callgraph
    -callscc   => print-callgraph-sccs
    -cfgscc    => print-cfg-sccs
    -externalfnconstants => print-externalfnconstants
    -print               => print-function
    -print-alias-sets (no change)
    -print-callgraph     => dot-callgraph
    -print-cfg           => dot-cfg
    -print-cfg-only      => dot-cfg-only
    -print-dom-info (no change)
    -printm              => print-module
    -printusedtypes      => print-used-types

llvm-svn: 56487
2008-09-23 12:47:39 +00:00
Duncan Sands 310077034a Remove the MarkModRef pass (use AddReadAttrs instead).
Unfortunately this means removing one regression test
of GlobalsModRef because I couldn't work out how to
perform it without MarkModRef.

llvm-svn: 56342
2008-09-19 08:23:44 +00:00
Duncan Sands af25ee7ffc Add a new pass AddReadAttrs which works out which functions
can get the readnone/readonly attributes, and gives them it.
The plan is to remove markmodref (which did the same thing
by querying GlobalsModRef) and delete the analogous
functionality from GlobalsModRef.

llvm-svn: 56341
2008-09-19 08:17:05 +00:00
Duncan Sands 938e8f60d6 Teach -callgraph to always print the callgraph (as the
description says it does), not just when -analyze is
used as well.  This means printing to stderr, so adjust
some tests.

llvm-svn: 56337
2008-09-19 07:57:09 +00:00
Dan Gohman dc5f5cbe59 Finally re-apply r46959. This is made feasible by the combination
of r56230, r56232, and r56246.

llvm-svn: 56247
2008-09-16 18:52:57 +00:00
Dan Gohman 162568842e Fix spacing in the grep line for this test, following the recent
SCEV-whitespace changes.

llvm-svn: 56234
2008-09-16 01:37:08 +00:00
Dan Gohman f9081a2cd5 Teach ScalarEvolution to consider loop preheaders in the search for
an if statement that guards a loop, to allow indvars to avoid smax
operations in more situations.

llvm-svn: 56232
2008-09-15 22:18:04 +00:00
Dan Gohman 81313fd8d1 Fix WriteAsOperand to not emit a leading space character. Adjust
its callers to emit a space character before calling it when a
space is needed.

This fixes several spurious whitespace issues in
ScalarEvolution's debug dumps. See the test changes for
examples.

This also fixes odd space-after-tab indentation in the output
for switch statements, and changes calls from being printed like
this:
  call void @foo( i32 %x )
to this:
  call void @foo(i32 %x)

llvm-svn: 56196
2008-09-14 17:21:12 +00:00
Duncan Sands 9ddb3145ae Fix PR2792: treat volatile loads as writing memory somewhere.
Treat stores as reading memory, just to play safe.

llvm-svn: 56188
2008-09-13 12:45:50 +00:00
Duncan Sands c189e79440 Correct callgraph construction. It has two problems:
(1) code left over from the days of ConstantPointerRef:
if a use of a function is a GlobalValue then that is
not considered a reason to add an edge from the external
node, even though the use may be as an initializer for
an externally visible global!  There might be some point
to this behaviour when the use is by an alias (though the
code predated aliases by some centuries), but I think
PR2782 is a better way of handling that.  (2) If function
F calls function G, and also G is a parameter to the
call, then an F->G edge is not added to the callgraph.
While this doesn't seem to matter much, adding such an
edge makes the callgraph more regular.
In addition, the new code should be faster as well as
simpler.

llvm-svn: 55987
2008-09-09 12:40:47 +00:00
Duncan Sands b86a788862 Testcase for commits 55700 and 55714.
llvm-svn: 55715
2008-09-03 19:38:41 +00:00
Duncan Sands 0eca0571f8 Since onlyReadsMemory returns true if in fact
doesNotAccessMemory, check doesNotAccessMemory
first, since otherwise functions may be
marked readonly rather than readnone.

llvm-svn: 55697
2008-09-03 15:31:24 +00:00
Duncan Sands 42c644ef03 Cleanup GlobalsModRef a bit. When analysing the
callgraph, when one member of a SCC calls another
then the analysis would drop to mod-ref because
there is (usually) no function info for the callee
yet; fix this.  Teach the analysis about function
attributes, in particular the readonly attribute
(which requires being careful about globals).

llvm-svn: 55696
2008-09-03 12:55:42 +00:00
Owen Anderson 2a6adfa4f0 Remove GCSE and LoadVN from the testsuite.
llvm-svn: 54832
2008-08-16 00:00:54 +00:00
Dan Gohman 2a62fd96a6 Extend ScalarEvolution's executesAtLeastOnce logic to be able to
continue past the first conditional branch when looking for a
relevant test. This helps it avoid using MAX expressions in
loop trip counts in more cases.

llvm-svn: 54697
2008-08-12 20:17:31 +00:00
Eli Friedman 61f67624c3 PR2621: Improvements to the SCEV AddRec binomial expansion. This
version uses a new algorithm for evaluating the binomial coefficients 
which is significantly more efficient for AddRecs of more than 2 terms 
(see the comments in the code for details on how the algorithm works).  
It also fixes some bugs: it removes the arbitrary length restriction for 
AddRecs, it fixes the silent generation of incorrect code for AddRecs 
which require a wide calculation width, and it fixes an issue where we 
were incorrectly truncating the iteration count too far when evaluating 
an AddRec expression narrower than the induction variable.

There are still a few related issues I know of: I think there's 
still an issue with the SCEVExpander expansion of AddRec in terms of
the width of the induction variable used.  The hack to avoid generating 
too-wide integers shouldn't be necessary; instead, the callers should be 
considering the cost of the expansion before expanding it (in addition 
to not expanding too-wide integers, we might not want to expand 
expressions that are really expensive, especially when optimizing for 
size; calculating an length-17 32-bit AddRec currently generates about 250 
instructions of straight-line code on X86).  Also, for long 32-bit 
AddRecs on X86, CodeGen really sucks at scheduling the code.  I'm planning on 
filing follow-up PRs for these issues.

llvm-svn: 54332
2008-08-04 23:49:06 +00:00
Eli Friedman 4736916aa6 Another SCEV issue from PR2607; essentially the same issue, but this
time applying to the implicit comparison in smin expressions. The 
correct way to transform an inequality into the opposite 
inequality, either signed or unsigned, is with a not expression.

I looked through the SCEV code, and I don't think there are any more 
occurrences of this issue.

llvm-svn: 54194
2008-07-30 04:36:32 +00:00