152 Commits

Author SHA1 Message Date
Nick Lewycky
d9573d899d When comparing constants, consider a less wide constant to be "less complex"
than a wider one, before trying to compare their contents which will crash
if their sizes are different.

llvm-svn: 74792
2009-07-04 17:24:52 +00:00
Andreas Bolka
71ef361d1d Array accesses are independent if the underlying arrays differ.
llvm-svn: 74499
2009-06-30 02:12:10 +00:00
Andreas Bolka
bed5622fb7 Print pairwise dependence results, add testcases.
llvm-svn: 74402
2009-06-28 00:35:22 +00:00
Dan Gohman
60844e20f0 Add a testcase demoing some of ScalarEvolution's new trip count logic.
llvm-svn: 74049
2009-06-24 01:22:30 +00:00
Dan Gohman
058143a236 Fix a bug in the trip-count computation with And/Or. If either of the
sides is CouldNotCompute, the resulting exact count must be CouldNotCompute.

llvm-svn: 73920
2009-06-22 23:28:56 +00:00
Dan Gohman
b85ac02513 Fix llvm::ComputeNumSignBits to handle pointer types
conservatively correctly, instead of aborting.

llvm-svn: 73908
2009-06-22 22:02:32 +00:00
Dan Gohman
db7860aa40 Teach ScalarEvolution how to analyze loops with multiple exit
blocks, and also exit blocks with multiple conditions (combined
with (bitwise) ands and ors). It's often infeasible to compute an
exact trip count in such cases, but a useful upper bound can often
be found.

llvm-svn: 73866
2009-06-22 00:31:57 +00:00
Dan Gohman
eb0a67278b Fix ScalarEvolution's backedge-taken count computations to check for
overflow when computing a integer division to round up.

Thanks to Nick Lewycky for noticing this!

llvm-svn: 73862
2009-06-21 23:46:38 +00:00
Dan Gohman
e72fd546a2 Teach ScalarEvolution how to recognize another xor(and(x, C), C) case.
If C is a single bit and the and gets analyzed as a truncate and
zero-extend, the xor can be represnted as an add.

llvm-svn: 73664
2009-06-18 00:00:20 +00:00
Dan Gohman
50b7d0d843 Add -disable-output to a bunch of tests that don't care about the output.
llvm-svn: 73633
2009-06-17 20:56:26 +00:00
Dan Gohman
473789f75a Fix ScalarEvolution's Xor handling to not assume that an And
that gets recognized with a SCEVZeroExtendExpr must be an And
with a low-bits mask. With r73540, this is no longer the case.

llvm-svn: 73594
2009-06-17 01:22:39 +00:00
Dan Gohman
5f6f8101d5 Split the Add, Sub, and Mul instruction opcodes into separate
integer and floating-point opcodes, introducing
FAdd, FSub, and FMul.

For now, the AsmParser, BitcodeReader, and IRBuilder all preserve
backwards compatability, and the Core LLVM APIs preserve backwards
compatibility for IR producers. Most front-ends won't need to change
immediately.

This implements the first step of the plan outlined here:
http://nondot.org/sabre/LLVMNotes/IntegerOverflow.txt

llvm-svn: 72897
2009-06-04 22:49:04 +00:00
Dan Gohman
5dd6f54a5f Teach BasicAliasAnalysis to understand constant gep indices that fall
beyond their associated static array type.

I believe that this fixes a legitimate bug, because BasicAliasAnalysis
already has code to check for this condition that works for non-constant
indices, however it was missing the case of constant indices. With this
change, it checks for both.

This fixes PR4267, and miscompiles of SPEC 188.ammp and 464.h264.href.

llvm-svn: 72451
2009-05-27 01:48:27 +00:00
Dan Gohman
592d65ba06 Teach ScalarEvolution to recognize x^-1 in the case where non-demanded
bits have been stripped out by instcombine.

llvm-svn: 72010
2009-05-18 16:29:04 +00:00
Dan Gohman
2c9bd7e0cb Make ScalarEvolution::isLoopGuardedByCond work even when the edge
entering a loop is a non-split critical edge.

llvm-svn: 72004
2009-05-18 15:36:09 +00:00
Dan Gohman
904f081ce7 Add nounwind to a few tests.
llvm-svn: 72002
2009-05-18 15:16:49 +00:00
Eli Friedman
aec1764402 Allow scalar evolution to compute iteration counts for loops with a
pointer-based condition.  This fixes PR3171.

llvm-svn: 71354
2009-05-09 12:32:42 +00:00
Dan Gohman
141989d3c2 Fix bogus overflow checks by replacing them with actual
overflow checks.

llvm-svn: 71284
2009-05-08 23:11:16 +00:00
Dan Gohman
603f022049 Fold trunc casts into add-recurrence expressions, allowing the
add-recurrence to be exposed. Add a new SCEV folding rule to
help simplify expressions in the presence of these extra truncs.

llvm-svn: 71264
2009-05-08 21:03:19 +00:00
Dan Gohman
0dc2b769b0 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
3c9f4f765c 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
06aff30f01 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
9fa631c81a Fix this test to match the new output from scalar-evolution.
llvm-svn: 70410
2009-04-29 21:06:20 +00:00
Dan Gohman
55befacc69 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
211c5de27d Fix a grammaro in a comment.
llvm-svn: 70331
2009-04-28 21:54:23 +00:00
Nick Lewycky
32cfba44df 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
0c0498a365 Testcase for PR3909.
llvm-svn: 69868
2009-04-23 04:33:42 +00:00
Dan Gohman
19990f2310 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
f8afc9ecda change this to test for an alias result more directly.
llvm-svn: 67046
2009-03-16 18:28:27 +00:00
Nick Lewycky
d271c19fea 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
5972bc6234 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
06c6037d9f Update this test for the LoopInfo::print changes.
llvm-svn: 65597
2009-02-27 00:17:49 +00:00
Dan Gohman
dd9c79d45b 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
f6c8dc0825 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
c418b82207 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
911bb6122c 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
2c01a8db3d 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
bb69bd55a4 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
8f96b51785 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
905350a341 Remove empty test.
llvm-svn: 61095
2008-12-16 19:07:17 +00:00
Bill Wendling
f807a68f2e 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
1b0fc83809 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
0e79aa6595 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
51228d6707 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
312d95be37 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
e2b5854e41 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
35f9ef25f1 xfail this for now.
llvm-svn: 60777
2008-12-09 18:43:00 +00:00
Nick Lewycky
41060b1556 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
47fa9bd187 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
c573f70ae4 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