Commit Graph

7088 Commits

Author SHA1 Message Date
Sanjay Patel
549121305a move a single test case to where most other instcombine shuffle bug test cases exist
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253784 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-21 16:12:58 +00:00
NAKAMURA Takumi
2bdcd86819 Move free-zext.ll to llvm/test/Transforms/CodeGenPrepare/AArch64/
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253730 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 22:55:34 +00:00
Owen Anderson
108258ac78 Fix another infinite loop in Reassociate caused by Constant::isZero().
Not all zero vectors are ConstantDataVector's.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253723 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 22:34:48 +00:00
Geoff Berry
2d2aadfa70 [CodeGenPrepare] Create more extloads and fewer ands
Summary:
Add and instructions immediately after loads that only have their low
bits used, assuming that the (and (load x) c) will be matched as a
extload and the ands/truncs fed by the extload will be removed by isel.

Reviewers: mcrosier, qcolombet, ab

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14584

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253722 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 22:34:39 +00:00
Diego Novillo
15d2198650 SamplePGO - Tweak RUN command for a test. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253717 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 21:46:41 +00:00
Diego Novillo
ddec40be2c SamplePGO - Do not count never-executed inlined functions when computing coverage.
If a function was originally inlined but not actually hot at runtime,
its samples will not be counted inside the parent function. This throws
off the coverage calculation because it expects to find more used
records than it should.

Fixed by ignoring functions that will not be inlined into the parent.
Currently, this is inlined functions with 0 samples.  In subsequent
patches, I'll change this to mean "cold" functions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253716 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 21:46:38 +00:00
Diego Novillo
c6b24c2806 SamplePGO - Add line offset and discriminator information to sample reports.
While debugging some sampling coverage problems, I found this useful:
When applying samples from a profile, it helps to also know what line
offset and discriminator the sample belongs to. This makes it easy to
correlate against the input profile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253670 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 15:39:42 +00:00
Owen Anderson
3f9c2909a5 Fix a pair of issues that caused an infinite loop in reassociate.
Terrifyingly, one of them is a mishandling of floating point vectors
in Constant::isZero().  How exactly this issue survived this long
is beyond me.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253655 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 08:16:13 +00:00
Peter Collingbourne
5178bc957a ScalarEvolution: do not set nuw when creating exprs of form <expr> + <all-ones>.
The nuw constraint will not be satisfied unless <expr> == 0.

This bug has been around since r102234 (in 2010!), but was uncovered by
r251052, which introduced more aggressive optimization of nuw scev expressions.

Differential Revision: http://reviews.llvm.org/D14850

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253627 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-20 01:26:13 +00:00
Sanjay Patel
272898a425 [InstCombine] add tests to show missing trunc optimizations
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253609 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 22:11:52 +00:00
Sanjay Patel
634e1cb482 [InstCombine] add tests to show missing bitcast optimizations
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253602 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 21:32:25 +00:00
Dehao Chen
0a7baafe64 Reimplement discriminator assignment algorithm.
Summary: The new algorithm is more efficient (O(n), n is number of basic blocks). And it is guaranteed to cover all cases of multiple BB mapped to same line.

Reviewers: dblaikie, davidxl, dnovillo

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14738

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253594 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 19:53:05 +00:00
James Molloy
a6b4079da3 [GlobalOpt] Localize some globals that have non-instruction users
We currently bail out of global localization if the global has non-instruction users. However, often these can be simple bitcasts or constant-GEPs, which we can easily turn into instructions before localizing. Be a bit more aggressive.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253584 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 18:04:33 +00:00
Sanjay Patel
02857f7b46 this new test file was accidentally left out of r253573
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253574 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 16:39:00 +00:00
James Molloy
e30d17a4d7 [FunctionAttrs] Provide a mechanism for adding function attributes from the command line
This provides a way to force a function to have certain attributes from the command line. This can be useful when debugging or doing workload exploration, where manually editing IR is tedious or not possible (due to build systems etc).

The syntax is -force-attribute=function_name:attribute_name

All function attributes are parsed except alignstack as it requires an argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253550 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 08:49:57 +00:00
Elena Demikhovsky
43be5f580c Pointers in Masked Load, Store, Gather, Scatter intrinsics
The masked intrinsics support all integer and floating point data types. I added the pointer type to this list.
Added tests for CodeGen and for Loop Vectorizer.
Updated the Language Reference.

Differential Revision: http://reviews.llvm.org/D14150



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253544 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 07:17:16 +00:00
Pete Cooper
6d024c616a Revert "Change memcpy/memset/memmove to have dest and source alignments."
This reverts commit r253511.

This likely broke the bots in
http://lab.llvm.org:8011/builders/clang-ppc64-elf-linux2/builds/20202
http://bb.pgr.jp/builders/clang-3stage-i686-linux/builds/3787

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253543 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 05:56:52 +00:00
Weiming Zhao
f9d8b8d2ab Fix bug 25440: GVN assertion after coercing loads
Optimizations like LoadPRE in GVN will insert new instructions.
If the insertion point is in a already processed BB, they should
get a value number explicitly. If the insertion point is after
current instruction, then just leave it. However, current GVN framework
has no support for it.
In this patch, we just bail out if a VN can't be found.

Dfferential Revision: http://reviews.llvm.org/D14670

A    test/Transforms/GVN/pr25440.ll
M    lib/Transforms/Scalar/GVN.cpp


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253536 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-19 02:45:18 +00:00
Davide Italiano
b8dd4a3d67 [SimplifyLibCalls] New trick: pow(x, 0.5) -> sqrt(x) under -ffast-math.
Differential Revision:	http://reviews.llvm.org/D14466


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253521 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-18 23:21:32 +00:00
Pete Cooper
8b170f7f29 Change memcpy/memset/memmove to have dest and source alignments.
Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html

These intrinsics currently have an explicit alignment argument which is
required to be a constant integer.  It represents the alignment of the
source and dest, and so must be the minimum of those.

This change allows source and dest to each have their own alignments
by using the alignment attribute on their arguments.  The alignment
argument itself is removed.

There are a few places in the code for which the code needs to be
checked by an expert as to whether using only src/dest alignment is
safe.  For those places, they currently take the minimum of src/dest
alignments which matches the current behaviour.

For example, code which used to read:
  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 500, i32 8, i1 false)
will now read:
  call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 8 %dest, i8* align 8 %src, i32 500, i1 false)

For out of tree owners, I was able to strip alignment from calls using sed by replacing:
  (call.*llvm\.memset.*)i32\ [0-9]*\,\ i1 false\)
with:
  $1i1 false)

and similarly for memmove and memcpy.

I then added back in alignment to test cases which needed it.

A similar commit will be made to clang which actually has many differences in alignment as now
IRBuilder can generate different source/dest alignments on calls.

In IRBuilder itself, a new argument was added.  Instead of calling:
  CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, /* isVolatile */ false)
you now call
  CreateMemCpy(Dst, Src, getInt64(Size), DstAlign, SrcAlign, /* isVolatile */ false)

There is a temporary class (IntegerAlignment) which takes the source alignment and rejects
implicit conversion from bool.  This is to prevent isVolatile here from passing its default
parameter to the source alignment.

Note, changes in future can now be made to codegen.  I didn't change anything here, but this
change should enable better memcpy code sequences.

Reviewed by Hal Finkel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253511 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-18 22:17:24 +00:00
Mike Aizatsky
54225a9153 Disable gvn non-local speculative loads under asan.
Summary: Fix for https://llvm.org/bugs/show_bug.cgi?id=25550

Differential Revision: http://reviews.llvm.org/D14763

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253498 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-18 20:43:00 +00:00
Igor Laevsky
a90859a6e3 Revert "Revert "Strip metadata when speculatively hoisting instructions (r252604)"
Failing clang test is now fixed by the r253458.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253459 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-18 14:50:18 +00:00
Sanjoy Das
aca8112442 Teach the inliner to track deoptimization state
Summary:
This change teaches LLVM's inliner to track and suitably adjust
deoptimization state (tracked via deoptimization operand bundles) as it
inlines through call sites.  The operation is described in more detail
in the LangRef changes.

Reviewers: reames, majnemer, chandlerc, dexonsmith

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14552

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253438 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-18 06:23:38 +00:00
David Majnemer
4db6dc51b0 Add a test for r253323
Forgot to do this simultaneously with committing the fix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253430 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-18 02:50:39 +00:00
Andrew Kaylor
881fcaec6b [EH] Keep filter clauses for types that have been caught.
The instruction combiner previously removed types from filter clauses in Landing Pad instructions if the type had previously been seen in a catch clause.  This is incorrect and prevents unexpected exception handlers from rethrowing the caught type.

Differential Revision: http://reviews.llvm.org/D14669



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253370 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-17 20:13:04 +00:00
Elena Demikhovsky
741a772213 Vector of pointers in function attributes calculation
While setting function attributes we check all instructions that may access memory. For a call instruction we check all arguments. The special check is required for pointers.
I added vector-of-pointers to the call arguments types that should be checked.

Differential Revision: http://reviews.llvm.org/D14693



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253363 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-17 19:30:51 +00:00
Philip Reames
1836bbe6cd [PRE] Preserve !invariant.load metadata
Spoted via inspection.  Test case included.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253275 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-17 00:15:09 +00:00
Owen Anderson
2a949077a9 Add intermediate subtract instructions to reassociation worklist.
We sometimes create intermediate subtract instructions during
reassociation.  Adding these to the worklist to revisit exposes many
additional reassociation opportunities.

Patch by Aditya Nandakumar.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253240 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-16 18:07:30 +00:00
David Majnemer
578dced0a1 [LoopStrengthReduce] Don't increment iterator past the end of the BB
We tried to move the insertion point beyond instructions like landingpad
and cleanuppad.
However, we *also* tried to move past catchpad.  This is problematic
because catchpad is also a terminator.

This fixes PR25541.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253238 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-16 17:37:58 +00:00
Pavel Labath
168146e84b Don't generate discriminators for calls to debug intrinsics
Summary:
This fails a check in Verifier.cpp, which checks for location matches between the declared
variable and the !dbg attachments.

Reviewers: dnovillo, dblaikie, danielcdh

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14657

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253194 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-16 10:40:38 +00:00
Keno Fischer
888d479702 [Sink] Don't move landingpads
Summary: Moving landingpads into successor basic blocks makes the
verifier sad. Teach Sink that much like PHI nodes and terminator
instructions, landingpads (and cleanuppads, etc.) may not be moved
between basic blocks.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14475

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253182 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-16 04:47:58 +00:00
James Molloy
fb7bc35602 [GlobalOpt] Demote globals to locals more aggressively
Global to local demotion can speed up programs that use globals a lot. It is particularly useful with LTO, when the entire call graph is known and most functions have been internalized.

For a global to be demoted, it must only be accessed by one function and that function:
  1. Must never recurse directly or indirectly, else the GV would be clobbered.
  2. Must never rely on the value in GV at the start of the function (apart from the initializer).

GlobalOpt can already do this, but it is hamstrung and only ever tries to demote globals inside "main", because C++ gives extra guarantees about how main is called - once and only once.

In LTO mode, we can often prove the first property (if the function is internal by this point, we know enough about the callgraph to determine if it could possibly recurse). FunctionAttrs now infers the "norecurse" attribute for this reason.

The second property can be proven for a subset of functions by proving that all loads from GV are dominated by a store to GV. This is conservative in the name of compile time - this only requires a DominatorTree which is fairly cheap in the grand scheme of things. We could do more fancy stuff with MemoryDependenceAnalysis too to catch more cases but this appears to catch most of the useful ones in my testing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253168 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-15 14:21:37 +00:00
Elena Demikhovsky
f79c5ce90b Fixed GEP visitor in the InstCombine pass.
The current implementation of GEP visitor in InstCombine fails with assertion on Vector GEP with mix of scalar and vector types, like this:

getelementptr double, double* %a, <8 x i32> %i
(It fails to create a "sext" from <8 x i32> to <8 x i64>)

I fixed it and added some tests.

Differential Revision: http://reviews.llvm.org/D14485



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253162 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-15 08:19:35 +00:00
Michael Zolotukhin
09dcb16d13 Don't recompute LCSSA after loop-unrolling when possible.
Summary:
Currently we always recompute LCSSA for outer loops after unrolling an
inner loop. That leads to compile time problem when we have big loop
nests, and we can solve it by avoiding unnecessary work. For instance,
if w eonly do partial unrolling, we don't break LCSSA, so we don't need
to rebuild it. Also, if all exits from the inner loop are inside the
enclosing loop, then complete unrolling won't break LCSSA either.

I replaced unconditional LCSSA recomputation with conditional recomputation +
unconditional assert and added several tests, which were failing when I
experimented with it.

Soon I plan to follow up with a similar patch for recalculation of dominators
tree.

Reviewers: hfinkel, dexonsmith, bogner, joker.eph, chandlerc

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14526

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253126 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-14 05:51:41 +00:00
Chad Rosier
2588aa9425 [LIR] Add support for creating memcpys from loops with a negative stride.
This allows us to transform the below loop into a memcpy.

void test(unsigned *__restrict__ a, unsigned *__restrict__ b) {
  for (int i = 2047; i >= 0; --i) {
    a[i] = b[i];
  }
}

This is the memcpy version of r251518, which added support for memset with
negative strided loops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253091 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-13 21:51:02 +00:00
Evgeniy Stepanov
e528e5711e [safestack] Rewrite isAllocaSafe using SCEV.
Use ScalarEvolution to calculate memory access bounds.
Handle function calls based on readnone/nocapture attributes.
Handle memory intrinsics with constant size.

This change improves both recall and precision of IsAllocaSafe.
See the new tests (ex. BitCastWide) for the kind of code that was wrongly
classified as safe.

SCEV efficiency seems to be limited by the fact the SafeStack runs late
(in CodeGenPrepare), and many loops are unrolled or otherwise not in LCSSA.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253083 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-13 21:21:42 +00:00
Nathan Slingerland
572e633224 [llvm-profdata] Add check for text profile formats and improve error reporting (2nd try)
Summary:
This change addresses two possible instances of user error / confusion when
merging sampled profile data.

Previously any input that didn't match the raw or processed instrumented format
would automatically be interpreted as instrumented profile text format data.
No error would be reported during the merge.

Example:
If foo-sampled.profdata and bar-sampled.profdata are binary sampled profiles:

Old behavior:
$ llvm-profdata merge foo-sampled.profdata bar-sampled.profdata -output foobar-sampled.profdata
$ llvm-profdata show -sample foobar-sampled.profdata
error: foobar-sampled.profdata:1: Expected 'mangled_name:NUM:NUM', found  lprofi

This change adds basic checks for valid input data when assuming text input.
It also makes error messages related to file format validity more specific about
the assumbed profile data type.

New behavior:
$ llvm-profdata merge foo-sampled.profdata bar-sampled.profdata -o foobar-sampled.profdata
error: foo.profdata: Unrecognized instrumentation profile encoding format
Perhaps you forgot to use the -sample option?

Reviewers: bogner, davidxl, dnovillo

Subscribers: davidxl, llvm-commits

Differential Revision: http://reviews.llvm.org/D14558

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253009 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-13 03:47:58 +00:00
Tobias Grosser
8887882603 Revert "Fix bug 25440: GVN assertion after coercing loads"
This reverts 252919 which broke LNT: MultiSource/Applications/SPASS

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252936 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-12 20:04:21 +00:00
Weiming Zhao
13d37da28f Fix bug 25440: GVN assertion after coercing loads
Summary:
when coercing loads, it inserts some instructions, which have no GV assigned.

https://llvm.org/bugs/show_bug.cgi?id=25440


Reviewers: hfinkel, dberlin

Subscribers: dberlin, llvm-commits

Differential Revision: http://reviews.llvm.org/D14479

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252919 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-12 18:19:59 +00:00
James Molloy
7086a4139d [InstCombine] Add trivial folding (bitreverse (bitreverse x)) -> x
There are plenty more instcombines we could probably do with bitreverse, but this seems like a very obvious and trivial starting point and was brought up by Hal in his review.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252879 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-12 12:39:41 +00:00
James Molloy
29020c0a61 Revert "Revert "[FunctionAttrs] Identify norecurse functions""
This reapplies this patch, with test fixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252871 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-12 10:55:20 +00:00
James Molloy
6cd07b45e1 Revert "[FunctionAttrs] Identify norecurse functions"
This reverts commit r252862. This introduced test failures and I'm reverting while I investigate how this happened.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252863 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-12 09:05:43 +00:00
James Molloy
31d4df2fc6 [FunctionAttrs] Identify norecurse functions
A function can be marked as norecurse if:
  * The SCC to which it belongs has cardinality 1; and either
    a) It does not call any non-norecurse function. This includes self-recursion; or
    b) It only has one callsite and the function that callsite is within is marked norecurse.

a) is best propagated bottom-up and b) is best propagated top-down.

We build up the norecurse attributes bottom-up using the existing SCC pass, and mark functions with no obvious recursion (but not provably norecurse) to sweep later, top-down.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252862 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-12 08:53:04 +00:00
Diego Novillo
95b12c8115 SamplePGO - Fix PR 25482 - Do not rely on llvm.dbg.cu for discriminators
The discriminators pass relied on the presence of llvm.dbg.cu to decide
whether to add discriminators, but this fails in the case where debug
info is only enabled partially when -fprofile-sample-use is active.

The reason llvm.dbg.cu is not present in these cases is to prevent
codegen from emitting debug info (as it is only used for the sample
profile pass).

This changes the discriminators pass to also emit discriminators even
when debug info is not being emitted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252763 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-11 17:54:37 +00:00
Sanjay Patel
03849aaa4e [MIPS] add overrides for isCheapToSpeculateCttz() and isCheapToSpeculateCtlz()
MIPS32 has instructions for efficient count-leading/trailing-zeros, so this should be
considered a cheap operation (and therefore fair game for speculation) for any MIPS32
implementation.

The net result of allowing this speculation for the regression tests in this patch is
that we get this code:

ctlz:
  jr  $ra
  clz  $2, $4

cttz:
  addiu  $1, $4, -1
  not  $2, $4
  and  $1, $2, $1
  clz  $1, $1
  addiu  $2, $zero, 32
  jr  $ra
  subu  $2, $2, $1

Instead of:

ctlz:
  beqz  $4, $BB0_2
  addiu  $2, $zero, 32
  clz  $2, $4
$BB0_2:
  jr  $ra
  nop

cttz:
  beqz  $4, $BB1_2
  addiu  $2, $zero, 32
  addiu  $1, $4, -1
  not  $2, $4
  and  $1, $2, $1
  clz  $1, $1
  addiu  $2, $zero, 32
  subu  $2, $2, $1
$BB1_2:
  jr  $ra
  nop

See D14469 for the larger motivation.

Differential Revision: http://reviews.llvm.org/D14500



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252755 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-11 17:24:56 +00:00
Akira Hatanaka
97c1c6fe64 Sort the enums in Attributes.h in case insensitive alphabetical order.
Sort the enums in preparation for moving the attributes to a table-gen
file.

rdar://problem/19836465


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252692 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-11 02:11:46 +00:00
Sanjoy Das
662c69d8c2 [ValueTracking] Teach isImpliedCondition a new bitwise trick
Summary:
This change teaches isImpliedCondition to prove things like

  (A | 15) < L  ==>  (A | 14) < L

if the low 4 bits of A are known to be zero.

Depends on D14391

Reviewers: majnemer, reames, hfinkel

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14392

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252673 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-10 23:56:20 +00:00
Bill Schmidt
9e24ab7252 [PowerPC] Add an MI SSA peephole pass.
This patch adds a pass for doing PowerPC peephole optimizations at the
MI level while the code is still in SSA form.  This allows for easy
modifications to the instructions while depending on a subsequent pass
of DCE.  Both passes are very fast due to the characteristics of SSA.

At this time, the only peepholes added are for cleaning up various
redundancies involving the XXPERMDI instruction.  However, I would
expect this will be a useful place to add more peepholes for
inefficiencies generated during instruction selection.  The pass is
placed after VSX swap optimization, as it is best to let that pass
remove unnecessary swaps before performing any remaining clean-ups.

The utility of these clean-ups are demonstrated by changes to four
existing test cases, all of which now have tighter expected code
generation.  I've also added Eric Schweiz's bugpoint-reduced test from
PR25157, for which we now generate tight code.  One other test started
failing for me, and I've fixed it
(test/Transforms/PlaceSafepoints/finite-loops.ll) as well; this is not
related to my changes, and I'm not sure why it works before and not
after.  The problem is that the CHECK-NOT: of "statepoint" from test1
fails because of the "statepoint" in test2, and so forth.  Adding a
CHECK-LABEL in between keeps the different occurrences of that string
properly scoped.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252651 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-10 21:38:26 +00:00
Sanjay Patel
da103fa05e [ARM] add overrides for isCheapToSpeculateCttz() and isCheapToSpeculateCtlz()
ARM V6T2 has instructions for efficient count-leading/trailing-zeros, so this should be
considered a cheap operation (and therefore fair game for speculation) for any ARM V6T2
implementation.

The net result of allowing this speculation for the regression tests in this patch is
that we get this code:

ctlz:               
  clz  r0, r0
  bx  lr
cttz:              
  rbit  r0, r0
  clz  r0, r0
  bx  lr

Instead of:

ctlz:    
  cmp  r0, #0
  moveq  r0, #32
  clzne  r0, r0
  bx  lr
cttz:     
  cmp   r0, #0
  moveq  r0, #32
  rbitne  r0, r0
  clzne  r0, r0
  bx  lr

This will help solve a general speculation/despeculation problem noted in PR24818:
https://llvm.org/bugs/show_bug.cgi?id=24818

Differential Revision: http://reviews.llvm.org/D14469



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252639 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-10 19:24:31 +00:00
Philip Reames
6054badbdd [ValueTracking] Recognize that and(x, add (x, -1)) clears the low bit
This is a cleaned up version of a patch by John Regehr with permission. Originally found via the souper tool.

If we add an odd number to x, then bitwise-and the result with x, we know that the low bit of the result must be zero. Either it was zero in x originally, or the add cleared it in the temporary value. As a result, one of the two values anded together must have the bit cleared.

Differential Revision: http://reviews.llvm.org/D14315



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252629 91177308-0d34-0410-b5e6-96231b3b80d8
2015-11-10 18:46:14 +00:00