Commit Graph

4320 Commits

Author SHA1 Message Date
Richard Osborne
47bd469b8a Add missing : in CHECK line.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164540 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-24 17:22:43 +00:00
Richard Osborne
bdc76fc75a Add missing check for presence of target data.
This avoids a crash in visitAllocaInst when target data isn't available.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164539 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-24 17:10:03 +00:00
Chandler Carruth
bc4021f31e Address one of the original FIXMEs for the new SROA pass by implementing
integer promotion analogous to vector promotion. When there is an
integer alloca being accessed both as its integer type and as a narrower
integer type, promote the narrower access to "insert" and "extract" the
smaller integer from the larger one, and make the integer alloca
a candidate for promotion.

In the new formulation, we don't care about target legal integer or use
thresholds to control things. Instead, we only perform this promotion to
an integer type which the frontend has already emitted a load or store
for. This bounds the scope and prevents optimization passes from
coalescing larger and larger entities into a single integer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164479 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-24 00:34:20 +00:00
Chandler Carruth
02e92a0b5d Switch to a signed representation for the dynamic offsets while walking
across the uses of the alloca. It's entirely possible for negative
numbers to come up here, and in some rare cases simply doing the 2's
complement arithmetic isn't the correct decision. Notably, we can't zext
the index of the GEP. The definition of GEP is that these offsets are
sign extended or truncated to the size of the pointer, and then wrapping
2's complement arithmetic used.

This patch fixes an issue that comes up with *no* input from the
buildbots or bootstrap afaict. The only place where it manifested,
disturbingly, is Clang's own regression test suite. A reduced and
targeted collection of tests are added to cope with this. Note that I've
tried to pin down the potential cases of overflow, but may have missed
some cases. I've tried to add a few cases to test this, but its hard
because LLVM has quite limited support for >64bit constructs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164475 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-23 11:43:14 +00:00
Chandler Carruth
d54a6b56a9 Fix a case where the new SROA pass failed to zap dead operands to
selects with a constant condition. This resulted in the operands
remaining live through the SROA rewriter. Most of the time, this just
caused some dead allocas to persist and get zapped by later passes, but
in one case found by Joerg, it caused a crash when we tried to *promote*
the alloca despite it having this dead use. We already have the
mechanisms in place to handle this, just wire select up to them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164427 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-21 23:36:40 +00:00
Benjamin Kramer
28aff84ceb LoopIdiom: Give up when the loop is not in canonical form.
We rely on it when doing the transforms. This can happen when there is an
indirectbr in  the loop.

Fixes PR13892.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164383 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-21 17:27:23 +00:00
Benjamin Kramer
e5bd3cf000 InstCombine: Make sure we use the pre-zext type when creating a constant of a value that is zext'd.
Fixes PR13250.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164377 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-21 16:26:41 +00:00
Manman Ren
554da1a222 SimplifyCFG: sink common codes from IF, ELSE blocks down to END block.
We already have HoistThenElseCodeToIf, this patch implements
SinkThenElseCodeToEnd. When END block has only two predecessors and each
predecessor terminates with unconditional branches, we compare instructions in
IF and ELSE blocks backwards and check whether we can sink the common
instructions down.

rdar://12191395


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164325 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-20 22:37:36 +00:00
Hans Wennborg
57933e3481 SimplifyCFG: Don't generate invalid code for switch used to initialize
two variables where the first variable is returned and the second
ignored.

I don't think this occurs in practice (other passes should have cleaned
up the unused phi node), but it should still be handled correctly.

Also make the logic for determining if we should return early less
sketchy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164225 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-19 14:24:21 +00:00
Hans Wennborg
c4ba62ca1d Move load_to_switch.ll to test/CodeGen/SPARC/
Because the test invokes llc -march=sparc, it needs to be in a directory
which is only run when the sparc target is built.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164211 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-19 09:25:03 +00:00
Nadav Rotem
f252441239 rename test
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164210 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-19 09:22:17 +00:00
Nadav Rotem
92df026f0d Prevent inlining of callees which allocate lots of memory into a recursive caller.
Example:

void foo() {
 ... foo();   // I'm recursive!

  bar();
}

bar() {  int a[1000];  // large stack size }

rdar://10853263



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164207 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-19 08:08:04 +00:00
Hans Wennborg
93ba133906 CodeGenPrep: turn lookup tables into switches for some targets.
This is a follow-up from r163302, which added a transformation to
SimplifyCFG that turns some switches into loads from lookup tables.

It was pointed out that some targets, such as GPUs and deeply embedded
targets, might not find this appropriate, but SimplifyCFG doesn't have
enough information about the target to decide this.

This patch adds the reverse transformation to CodeGenPrep: it turns
loads from lookup tables back into switches for targets where we do not
build jump tables (assuming these are also the targets where lookup
tables are inappropriate).

Hopefully we will eventually get to have target information in
SimplifyCFG, and then this CodeGenPrep transformation can be removed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164206 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-19 07:48:16 +00:00
Chandler Carruth
38f35fd3b7 Fix the last crasher I've gotten a reproduction for in SROA. This one
from the dragonegg build bots when we turned on the full version of the
pass. Included a much reduced test case for this pesky bug, despite
bugpoint's uncooperative behavior.

Also, I audited all the similar code I could find and didn't spot any
other cases where this mistake cropped up.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164178 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 22:37:19 +00:00
Andrew Trick
f08c115e6c LSR critical edge splitting fix for PR13756.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164147 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 17:51:33 +00:00
Chandler Carruth
7c8df7aa0c Fix getCommonType in a different way from the way I fixed it when
working on FCA splitting. Instead of refusing to form a common type when
there are uses of a subsection of the alloca as well as a use of the
entire alloca, just skip the subsection uses and continue looking for
a whole-alloca use with a type that we can use.

This produces slightly prettier IR I think, and also fixes the other
failure in the test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164146 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 17:49:37 +00:00
Benjamin Kramer
6ab4bd7145 XFAIL SROA test until Chandler can get to it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164128 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 14:27:53 +00:00
Chandler Carruth
9e3f639579 Fix a warning in release builds and a test case I forgot to update with
a fix to getCommonType in the previous patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164120 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 13:02:06 +00:00
Chandler Carruth
c370acdf96 Add a major missing piece to the new SROA pass: aggressive splitting of
FCAs. This is essential in order to promote allocas that are used in
struct returns by frontends like Clang. The FCA load would block the
rest of the pass from firing, resulting is significant regressions with
the bullet benchmark in the nightly test suite.

Thanks to Duncan for repeated discussions about how best to do this, and
to both him and Benjamin for review.

This appears to have blocked many places where the pass tries to fire,
and so I'm expect somewhat different results with this fix added.

As with the last big patch, I'm including a change to enable the SROA by
default *temporarily*. Ben is going to remove this as soon as the LNT
bots pick up the patch. I'm just trying to get a round of LNT numbers
from the stable machines in the lab.

NOTE: Four clang tests are expected to fail in the brief window where
this is enabled. Sorry for the noise!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164119 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 12:57:43 +00:00
Richard Osborne
d7cc8b839c Fix instcombine to obey requested alignment when merging allocas.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164117 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 09:31:44 +00:00
Manman Ren
222d6192ad PGO: preserve branch-weight metadata when simplifying Switch to a sub, an icmp
and a conditional branch; also when removing dead cases from a switch.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164084 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-18 00:47:33 +00:00
Manman Ren
b010277b59 PGO: preserve branch-weight metadata when simplifying Switch
Hanlde the case when we split the default edge if the default target has "icmp"
and unconditinal branch.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164076 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-17 23:07:43 +00:00
Manman Ren
b11cbe6b23 PGO: preserve branch-weight metadata when simplifying SwitchOnSelect.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164068 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-17 22:28:55 +00:00
Manman Ren
566540332f PGO: preserve branch-weight metadata when simplifying two branches with a common
destination in SimplifyCondBranchToCondBranch.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164054 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-17 21:30:40 +00:00
Chandler Carruth
1c8db50a9a Port the SSAUpdater-based promotion logic from the old SROA pass to the
new one, and add support for running the new pass in that mode and in
that slot of the pass manager. With this the new pass can completely
replace the old one within the pipeline.

The strategy for enabling or disabling the SSAUpdater logic is to do it
by making the requirement of the domtree analysis optional. By default,
it is required and we get the standard mem2reg approach. This is usually
the desired strategy when run in stand-alone situations. Within the
CGSCC pass manager, we disable requiring of the domtree analysis and
consequentially trigger fallback to the SSAUpdater promotion.

In theory this would allow the pass to re-use a domtree if one happened
to be available even when run in a mode that doesn't require it. In
practice, it lets us have a single pass rather than two which was
simpler for me to wrap my head around.

There is a hidden flag to force the use of the SSAUpdater code path for
the purpose of testing. The primary testing strategy is just to run the
existing tests through that path. One notable difference is that it has
custom code to handle lifetime markers, and one of the tests has been
enhanced to exercise that code.

This has survived a bootstrap and the test suite without serious
correctness issues, however my run of the test suite produced *very*
alarming performance numbers. I don't entirely understand or trust them
though, so more investigation is on-going.

To aid my understanding of the performance impact of the new SROA now
that it runs throughout the optimization pipeline, I'm enabling it by
default in this commit, and will disable it again once the LNT bots have
picked up one iteration with it. I want to get those bots (which are
much more stable) to evaluate the impact of the change before I jump to
any conclusions.

NOTE: Several Clang tests will fail because they run -O3 and check the
result's order of output. They'll go back to passing once I disable it
again.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163965 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-15 11:43:14 +00:00
Manman Ren
062986c2f0 PGO: preserve branch-weight metadata when simplifying two branches with a common
destination.

Updated previous implementation to fix a case not covered:
// PBI: br i1 %x, TrueDest, BB
// BI:  br i1 %y, TrueDest, FalseDest
The other case was handled correctly.
// PBI: br i1 %x, BB, FalseDest
// BI:  br i1 %y, TrueDest, FalseDest

Also tried to use 64-bit arithmetic instead of APInt with scale to simplify the
computation. Let me know if you have other opinions about this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163954 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-15 00:39:57 +00:00
Manman Ren
ad2890760f PGO: preserve branch-weight metadata when simplifying a switch with a single
case to a conditional branch and when removing dead cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163942 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-14 21:53:06 +00:00
Alex Rosenberg
eee94b3432 Review feedback from Duncan Sands. Alphabetize includes and simplify
lit config.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163928 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-14 19:19:57 +00:00
Manman Ren
a8a2b99aec PGO: preserve branch-weight metadata when merging two switches where
the default target of the first switch is not the basic block the second switch
is in (PredDefault != BB).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163916 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-14 17:29:56 +00:00
Chandler Carruth
713aa9431d Introduce a new SROA implementation.
This is essentially a ground up re-think of the SROA pass in LLVM. It
was initially inspired by a few problems with the existing pass:
- It is subject to the bane of my existence in optimizations: arbitrary
  thresholds.
- It is overly conservative about which constructs can be split and
  promoted.
- The vector value replacement aspect is separated from the splitting
  logic, missing many opportunities where splitting and vector value
  formation can work together.
- The splitting is entirely based around the underlying type of the
  alloca, despite this type often having little to do with the reality
  of how that memory is used. This is especially prevelant with unions
  and base classes where we tail-pack derived members.
- When splitting fails (often due to the thresholds), the vector value
  replacement (again because it is separate) can kick in for
  preposterous cases where we simply should have split the value. This
  results in forming i1024 and i2048 integer "bit vectors" that
  tremendously slow down subsequnet IR optimizations (due to large
  APInts) and impede the backend's lowering.

The new design takes an approach that fundamentally is not susceptible
to many of these problems. It is the result of a discusison between
myself and Duncan Sands over IRC about how to premptively avoid these
types of problems and how to do SROA in a more principled way. Since
then, it has evolved and grown, but this remains an important aspect: it
fixes real world problems with the SROA process today.

First, the transform of SROA actually has little to do with replacement.
It has more to do with splitting. The goal is to take an aggregate
alloca and form a composition of scalar allocas which can replace it and
will be most suitable to the eventual replacement by scalar SSA values.
The actual replacement is performed by mem2reg (and in the future
SSAUpdater).

The splitting is divided into four phases. The first phase is an
analysis of the uses of the alloca. This phase recursively walks uses,
building up a dense datastructure representing the ranges of the
alloca's memory actually used and checking for uses which inhibit any
aspects of the transform such as the escape of a pointer.

Once we have a mapping of the ranges of the alloca used by individual
operations, we compute a partitioning of the used ranges. Some uses are
inherently splittable (such as memcpy and memset), while scalar uses are
not splittable. The goal is to build a partitioning that has the minimum
number of splits while placing each unsplittable use in its own
partition. Overlapping unsplittable uses belong to the same partition.
This is the target split of the aggregate alloca, and it maximizes the
number of scalar accesses which become accesses to their own alloca and
candidates for promotion.

Third, we re-walk the uses of the alloca and assign each specific memory
access to all the partitions touched so that we have dense use-lists for
each partition.

Finally, we build a new, smaller alloca for each partition and rewrite
each use of that partition to use the new alloca. During this phase the
pass will also work very hard to transform uses of an alloca into a form
suitable for promotion, including forming vector operations, speculating
loads throguh PHI nodes and selects, etc.

After splitting is complete, each newly refined alloca that is
a candidate for promotion to a scalar SSA value is run through mem2reg.

There are lots of reasonably detailed comments in the source code about
the design and algorithms, and I'm going to be trying to improve them in
subsequent commits to ensure this is well documented, as the new pass is
in many ways more complex than the old one.

Some of this is still a WIP, but the current state is reasonbly stable.
It has passed bootstrap, the nightly test suite, and Duncan has run it
successfully through the ACATS and DragonEgg test suites. That said, it
remains behind a default-off flag until the last few pieces are in
place, and full testing can be done.

Specific areas I'm looking at next:
- Improved comments and some code cleanup from reviews.
- SSAUpdater and enabling this pass inside the CGSCC pass manager.
- Some datastructure tuning and compile-time measurements.
- More aggressive FCA splitting and vector formation.

Many thanks to Duncan Sands for the thorough final review, as well as
Benjamin Kramer for lots of review during the process of writing this
pass, and Daniel Berlin for reviewing the data structures and algorithms
and general theory of the pass. Also, several other people on IRC, over
lunch tables, etc for lots of feedback and advice.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163883 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-14 09:22:59 +00:00
Dan Gohman
b998913ff4 Handle the new !tbaa.struct metadata tags when converting a memcpy into scalar
loads and stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163844 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-13 21:51:01 +00:00
Benjamin Kramer
39acdb0200 MemCpyOpt: When forming a memset from stores also take GEP constexprs into account.
This is common when storing to global variables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163809 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-13 16:29:49 +00:00
Dan Gohman
0d1bc5f916 Detect overflow in the path count computation. rdar://12277446.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163739 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-12 20:45:17 +00:00
Manman Ren
ee99c7f1bf PGO: preserve branch-weight metadata when removing a case which jumps
to the default target.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163724 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-12 17:04:11 +00:00
Manman Ren
020aba0c3b SimplifyCFG: preserve branch-weight metadata when creating a new switch from
a pair of switch/branch where both depend on the value of the same variable and
the default case of the first switch/branch goes to the second switch/branch.

Code clean up and fixed a few issues:
1> handling the case where some cases of the 2nd switch are invalidated
2> correctly calculate the weight for the 2nd switch when it is a conditional eq

Testing case is modified from Alastair's original patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163635 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-11 17:43:35 +00:00
Alex Rosenberg
95f1ef4ac7 Add a pass that renames everything with metasyntatic names. This works well after using bugpoint to reduce the confusion presented by the original names, which no longer mean what they used to.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163592 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-11 02:46:18 +00:00
Andrew Trick
a344341849 Remove an incorrect assert during branch weight propagation.
Patch and test case by Alastair Murray!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163437 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-08 00:07:26 +00:00
Hans Wennborg
3bd51b8df3 Fix switch_to_lookup_table.ll test from r163302.
The lookup tables did not get built in a deterministic order.
This makes them get built in the order that the corresponding phi nodes
were found.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163305 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 10:10:35 +00:00
Hans Wennborg
486270aee6 Build lookup tables for switches (PR884)
This adds a transformation to SimplifyCFG that attemps to turn switch
instructions into loads from lookup tables. It works on switches that
are only used to initialize one or more phi nodes in a common successor
basic block, for example:

  int f(int x) {
    switch (x) {
    case 0: return 5;
    case 1: return 4;
    case 2: return -2;
    case 5: return 7;
    case 6: return 9;
    default: return 42;
  }

This speeds up the code by removing the hard-to-predict jump, and
reduces code size by removing the code for the jump targets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163302 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 09:43:28 +00:00
Manman Ren
408853ea16 JumpThreading: when default destination is the destination of some cases in a
switch, make sure we include the value for the cases when calculating edge
value from switch to the default destination.

rdar://12241132


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163270 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-05 23:45:58 +00:00
Dan Gohman
230768bd13 Make provenance checking conservative in cases when
pointers-to-strong-pointers may be in play. These can lead to retains and
releases happening in unstructured ways, foiling the optimizer. This fixes
rdar://12150909.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163180 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-04 23:16:20 +00:00
Nadav Rotem
7765492a7a LICM may hoist an instruction with undefined behavior above a trap.
Scan the body of the loop and find instructions that may trap.
Use this information when deciding if it is safe to hoist or sink instructions.
Notice that we can optimize the search of instructions that may throw in the case of nested loops.

rdar://11518836



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163132 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-04 10:25:04 +00:00
Bob Wilson
84451a110d Fix more fallout from r158919, similar to PR13547.
This code used to only handle malloc-like calls, which do not read memory.
r158919 changed it to check isNoAliasFn(), which includes strdup-like and
realloc-like calls, but it was not checking for dependencies on the memory
read by those calls.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163106 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-03 05:15:15 +00:00
Benjamin Kramer
7de7078933 LoopRotation: Make the brute force DomTree update more brute force.
We update until we hit a fixpoint. This is probably slow but also
slightly simplifies the code. It should also fix the occasional
invalid domtrees observed when building with expensive checking.

I couldn't find a case where this had a measurable slowdown, but
if someone finds a pathological case where it does we may have
to find a cleverer way of updating dominators here.

Thanks to Duncan for the test case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163091 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-02 11:57:22 +00:00
Michael Gottesman
cee2f72bfe [llvm] Updated the test fold-vector-select so that we test the vector selects exhaustively.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162953 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-30 23:11:49 +00:00
Benjamin Kramer
86c0d8c92f Fix test case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162913 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-30 15:42:45 +00:00
Benjamin Kramer
d70846ec1b LoopRotate: Also rotate loops with multiple exits.
The old PHI updating code in loop-rotate was replaced with SSAUpdater a while
ago, it has no problems with comples PHIs. What had to be fixed is detecting
whether a loop was already rotated and updating dominators when multiple exits
were present.

This change increases overall code size a bit, mostly due to additional loop
unrolling opportunities. Passes test-suite and selfhost with -verify-dom-info.
Fixes PR7447.

Thanks to Andy for the input on the domtree updating code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162912 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-30 15:39:42 +00:00
Nadav Rotem
639570c311 It is illegal to transform (sdiv (ashr X c1) c2) -> (sdiv x (2^c1 * c2)),
because C always rounds towards zero.

Thanks Dirk and Ben.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162899 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-30 11:23:20 +00:00
Benjamin Kramer
8e0d1c03ca Make MemoryBuiltins aware of TargetLibraryInfo.
This disables malloc-specific optimization when -fno-builtin (or -ffreestanding)
is specified. This has been a problem for a long time but became more severe
with the recent memory builtin improvements.

Since the memory builtin functions are used everywhere, this required passing
TLI in many places. This means that functions that now have an optional TLI
argument, like RecursivelyDeleteTriviallyDeadFunctions, won't remove dead
mallocs anymore if the TLI argument is missing. I've updated most passes to do
the right thing.

Fixes PR13694 and probably others.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162841 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-29 15:32:21 +00:00
Benjamin Kramer
aac7c650a6 InstCombine: Guard the transform introduced in r162743 against large ints and non-const shifts.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162751 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 13:08:13 +00:00
Nadav Rotem
a694e2a691 Make sure that we don't call getZExtValue on values > 64 bits.
Thanks Benjamin for noticing this.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162749 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 12:23:22 +00:00
Nadav Rotem
9753f0b9b4 Teach InstCombine to canonicalize [SU]div+[AL]shl patterns.
For example:
  %1 = lshr i32 %x, 2
  %2 = udiv i32 %1, 100

rdar://12182093




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162743 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 10:01:43 +00:00
Benjamin Kramer
7f07d2fbcf SimplifyLibCalls: Give all safely-shrinkable libcalls the same treatment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162383 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-22 19:39:15 +00:00
Chad Rosier
5f676fe139 Whitespace.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162370 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-22 17:34:11 +00:00
Chad Rosier
69b8e6295b Add test case for r162368.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162369 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-22 17:31:04 +00:00
Chandler Carruth
ec68f552f2 Port the global copy optimization from the SROA pass to InstCombine.
This optimization is really just replacing allocas wholesale with
globals, there is no scalarization.

The underlying motivation for this patch is to simplify the SROA pass
and focus it on splitting and promoting allocas.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162271 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-21 08:39:44 +00:00
Benjamin Kramer
a4b5717ea7 InstCombine: Fix a crasher when encountering a function pointer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162180 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-18 22:04:34 +00:00
Benjamin Kramer
00abcd3da0 InstCombine: Add a couple of fabs identities for comparing with 0.0.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162174 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-18 20:06:47 +00:00
Benjamin Kramer
2b74957106 SimplifyLibcalls: Add fabs and trunc to the list of libcalls that are safe to shrink from double to float.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162173 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-18 19:27:32 +00:00
Benjamin Kramer
168843c013 MemoryBuiltins: Properly guard ObjectSizeOffsetVisitor against cycles in the IR.
The previous fix only checked for simple cycles, use a set to catch longer
cycles too.

Drop the broken check from the ObjectSizeOffsetEvaluator. The BoundsChecking
pass doesn't have to deal with invalid IR like InstCombine does.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162120 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 19:26:41 +00:00
Benjamin Kramer
823573a381 Guard MemoryBuiltins against self-looping GEPs, which can occur in unreachable code due to constant propagation.
Fixes PR13621.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162098 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 14:16:37 +00:00
Benjamin Kramer
4e81d40545 Fix broken check lines.
I really need to find a way to automate this, but I can't come up with a regex
that has no false positives while handling tricky cases like custom check
prefixes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162097 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 12:28:26 +00:00
Rafael Espindola
0513059726 Teach GVN to reason about edges dominating uses. This allows it to handle cases
where some fact lake a=b dominates a use in a phi, but doesn't dominate the
basic block itself.

This feature could also be implemented by splitting critical edges, but at least
with the current algorithm reasoning about the dominance directly is faster.

The time for running "opt -O2" in the testcase in pr10584 is 1.003 times slower
and on gcc as a single file it is 1.0007 times faster.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162023 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-16 15:09:43 +00:00
Michael Liao
9441ad0b6e fix infinite loop in instcombine with more than 4GB memcpy
- memcpy size is wrongly truncated into 32-bit and treat 8GB memcpy is
  0-sized memcpy
- as 0-sized memcpy/memset is already removed before SimplifyMemTransfer
  and SimplifyMemSet in visitCallInst, replace 0 checking with
  assertions.
- replace getZExtValue() with getLimitedValue() according to
  Eli Friedman



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161923 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-15 03:49:59 +00:00
Craig Topper
750d7616c6 Change greater than to greater than or equal so that an identical sized store to the same offset is treated as completing overwriting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161857 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-14 07:32:05 +00:00
Nadav Rotem
3e883734fa During the CodeGenPrepare we often lower intrinsics (such as objsize)
and allow some optimizations to turn conditional branches into unconditional.
This commit adds a simple control-flow optimization which merges two consecutive
basic blocks which are connected by a single edge. This allows the codegen to
operate on larger basic blocks.

rdar://11973998



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161852 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-14 05:19:07 +00:00
Eli Friedman
6b951b25c3 The normal edge of an invoke is not allowed to branch to a block with a
landingpad.  Enforce it in the verifier, and fix the regression tests to match.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161697 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-10 20:55:20 +00:00
Pete Cooper
3eeba88631 Fix crash when when do lto on Bullet. Dynamic GEPs in SROA were incorrectly being applied to all accesses to an alloca, not just the ones which read from the GEP. Thanks to Evan for reducing the test. rdar://11861001
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161654 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-10 03:26:36 +00:00
Eli Friedman
1b88fc0122 isAllocLikeFn is allowed to return true for functions which read memory; make
sure we account for that correctly in DeadStoreElimination.  Fixes a regression
from r158919.  PR13547.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161468 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-08 02:17:32 +00:00
Dan Gohman
9d1747c3cd Avoid recomputing the unique exit blocks and their insert points when doing
multiple scalar promotions on a single loop. This also has the effect of
preserving the order of stores sunk out of loops, which is aesthetically
pleasing, and it happens to fix the testcase in PR13542, though it doesn't
fix the underlying problem.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161459 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-08 00:00:26 +00:00
Bob Wilson
f12c95a8af Fix a serious typo in InstCombine's optimization of comparisons.
An unsigned value converted to floating-point will always be greater than
a negative constant.  Unfortunately InstCombine reversed the check so that
unsigned values were being optimized to always be greater than all positive
floating-point constants.  <rdar://problem/12029145>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161452 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-07 22:35:16 +00:00
Benjamin Kramer
b6fdd022b7 PR13095: Give an inline cost bonus to functions using byval arguments.
We give a bonus for every argument because the argument setup is not needed
anymore when the function is inlined. With this patch we interpret byval
arguments as a compact representation of many arguments. The byval argument
setup is implemented in the backend as an inline memcpy, so to model the
cost as accurately as possible we take the number of pointer-sized elements
in the byval argument and give a bonus of 2 instructions for every one of
those. The bonus is capped at 8 elements, which is the number of stores
at which the x86 backend switches from an expanded inline memcpy to a real
memcpy. It would be better to use the real memcpy threshold from the backend,
but it's not available via TargetData.

This change brings the performance of c-ray in line with gcc 4.7. The included
test case tries to reproduce the c-ray problem to catch regressions for this
benchmark early, its performance is dominated by the inline decision of a
specific call.

This only has a small impact on most code, more on x86 and arm than on x86_64
due to the way the ABI works. When building LLVM for x86 it gives a small
inline cost boost to virtually any function using StringRef or STL allocators,
but only a 0.01% increase in overall binary size. The size of gcc compiled by
clang actually shrunk by a couple bytes with this patch applied, but not
significantly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161413 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-07 11:13:19 +00:00
Chandler Carruth
961e1acfb2 Fix PR13412, a nasty miscompile due to the interleaved
instsimplify+inline strategy.

The crux of the problem is that instsimplify was reasonably relying on
an invariant that is true within any single function, but is no longer
true mid-inline the way we use it. This invariant is that an argument
pointer != a local (alloca) pointer.

The fix is really light weight though, and allows instsimplify to be
resiliant to these situations: when checking the relation ships to
function arguments, ensure that the argumets come from the same
function. If they come from different functions, then none of these
assumptions hold. All credit to Benjamin Kramer for coming up with this
clever solution to the problem.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161410 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-07 10:59:59 +00:00
Chandler Carruth
e6450dc2af Add a much more conservative strategy for aligning branch targets.
Previously, MBP essentially aligned every branch target it could. This
bloats code quite a bit, especially non-looping code which has no real
reason to prefer aligned branch targets so heavily.

As Andy said in review, it's still a bit odd to do this without a real
cost model, but this at least has much more plausible heuristics.

Fixes PR13265.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161409 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-07 09:45:24 +00:00
Nadav Rotem
97baaeaeb2 When constant folding GEP expressions, keep the address space information of pointers.
Together with Ran Chachick <ran.chachick@intel.com>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160954 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-30 07:25:20 +00:00
Nick Lewycky
d64cb165d7 Add testcases for GlobalOpt changes in r160693 and r160757.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160925 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-29 01:15:37 +00:00
Nuno Lopes
e982de7be9 fix PR13390: do not loop forever with self-referencing self instructions
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160876 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-27 18:21:15 +00:00
Nuno Lopes
75564e3514 fix infinite loop in instcombine in the presence of a (malformed) self-referencing select inst.
This can happen as long as the instruction is not reachable. Instcombine does generate these unreachable malformed selects when doing RAUW

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160874 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-27 18:03:57 +00:00
Pete Cooper
7971de4178 Simplify demanded bits of select sources where the condition is a constant vector
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160835 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-26 23:10:24 +00:00
Pete Cooper
1121c786fc Teach SimplifyDemandedBits how to look through fpext and fptrunc to simplify their operand
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160823 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-26 22:37:04 +00:00
Duncan Sands
20b2d21509 Stop reassociate from looking through expressions of arbitrary complexity. This
is a temporary measure until my fix for PR13021 is ready.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160778 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-26 09:26:40 +00:00
Duncan Sands
6ce1eaf1a6 Don't perform an overaligned load in this test, since that's undefined
behaviour that might be exploited one day.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160714 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-25 09:45:37 +00:00
Duncan Sands
f2124cc6c1 When folding a load from a global constant, if the load started in the middle
of an array element (rather than at the beginning of the element) and extended
into the next element, then the load from the second element was being handled
wrong due to incorrect updating of the notion of which byte to load next.  This
fixes PR13442.  Thanks to Chris Smowton for reporting the problem, analyzing it
and providing a fix.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160711 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-25 09:14:54 +00:00
Nuno Lopes
9827c8e1c9 teach objectsize about strdup() and strndup()
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160676 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-24 16:28:13 +00:00
Nick Lewycky
8899d5c6fb Teach globalopt to not nuke all stores to globals. Keep them around of they
might be deliberate "one time" leaks, so that leak checkers can find them.
This is a reapply of r160602 with the fix that this time I'm committing the
code I thought I was committing last time; the I->eraseFromParent() goes
*after* the break out of the loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160664 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-24 07:21:08 +00:00
Dan Gohman
c72d3be389 An objc_retain can serve as a may-use for a different pointer.
rdar://11931823.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160637 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-23 19:27:31 +00:00
Nick Lewycky
c7088c9a9c Revert r160602.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160603 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-21 09:03:15 +00:00
Nick Lewycky
61e2ff8f82 Teach globalopt to play nice with leak checkers. This is a reapplication of
r160529 that was subsequently reverted. The fix was to not call
GV->eraseFromParent() right before the caller does the same. The existing
testcases already caught this bug if run under valgrind.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160602 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-21 08:29:45 +00:00
Nuno Lopes
78435f6bb7 move the bounds checking pass to the instrumentation folder, where it belongs. I dunno why in the world I dropped it in the Scalar folder in the first place.
No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160587 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-20 22:39:33 +00:00
Richard Osborne
dd2fb6c10b Fix assertion in jump threading (PR13405).
GetBestDestForJumpOnUndef() assumes there is at least 1 successor, which isn't
true if the block ends in an indirect branch with no successors. Fix this by
bailing out earlier in this case.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160546 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-20 10:36:17 +00:00
Nick Lewycky
4a96d0e44b Revert r160529 due to crashes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160532 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-19 23:59:21 +00:00
Nick Lewycky
39e357fafe Don't wipe out global variables that are probably storing pointers to heap
memory. This makes clang play nice with leak checkers.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160529 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-19 22:35:28 +00:00
Andrew Trick
2f3c326786 Added unit test for PR13361: LSR + SCEV "hangs" on reasonably sized test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160439 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-18 18:07:52 +00:00
Andrew Trick
4781d8ee1c indvars: Linear function test replace should avoid reusing undef.
Fixes PR13371: indvars pass incorrectly substitutes 'undef' values.

I do not like this fix. It's needed until/unless the meaning of undef
changes. It attempts to be complete according to the IR spec, but I
don't have much confidence in the implementation given the difficulty
testing undefined behavior. Worse, this invalidates some of my
hard-fought work on indvars and LSR to optimize pointer induction
variables. It results benchmark regressions, which I'll track
internally. On x86_64 no LTO I see:

-3% huffbench
-3% 400.perlbench
-8% fhourstones

My only suggestion for recovering is to change the meaning of
undef. If we could trust an arbitrary instruction to produce a some
real value that can be manipulated (e.g. incremented) according to
non-undef rules, then this case could be easily handled with SCEV.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160421 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-18 04:35:10 +00:00
Evan Cheng
a9e13ba3c8 Back out r160101 and instead implement a dag combine to recover from instcombine transformation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160387 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-17 18:54:11 +00:00
NAKAMURA Takumi
f30135c519 llvm/test/Transforms/LoopRotate/PhiRename-1.ll: FileCheck-ize. It fixes PR13301.
It began choking since Chandler's r159547, possibly due to improper expression on grep from TclParser to ShParser.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160367 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-17 15:43:17 +00:00
Nuno Lopes
d49981a9bb fix PR13339 (remove the predecessor from the unwind BB when removing an invoke)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160325 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-16 22:49:40 +00:00
Andrew Trick
e08c32249f LSR Fix: check SCEV expression safety before expansion.
All SCEV expressions used by LSR formulae must be safe to
expand. i.e. they may not contain UDiv unless we can prove nonzero
denominator.

Fixes PR11356: LSR hoists UDiv.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160205 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-13 23:33:10 +00:00
Evan Cheng
79590b8edf Instcombine was transforming:
%shr = lshr i64 %key, 3
  %0 = load i64* %val, align 8
  %sub = add i64 %0, -1
  %and = and i64 %sub, %shr
  ret i64 %and

to:
  %shr = lshr i64 %key, 3
  %0 = load i64* %val, align 8
  %sub = add i64 %0, 2305843009213693951
  %and = and i64 %sub, %shr
  ret i64 %and

The demanded bit optimization is actually a pessimization because add -1 would
be codegen'ed as a sub 1. Teach the demanded constant shrinking optimization
to check for negated constant to make sure it is actually reducing the width
of the constant.

rdar://11793464


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160101 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-12 01:45:35 +00:00
Nuno Lopes
78f8ef4217 instcombine: merge the functions that remove dead allocas and dead mallocs/callocs/...
This patch removes ~70 lines in InstCombineLoadStoreAlloca.cpp and makes both functions a bit more aggressive than before :)
In theory, we can be more aggressive when removing an alloca than a malloc, because an alloca pointer should never escape, but we are not taking advantage of this anyway

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159952 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-09 18:38:20 +00:00