Commit Graph

167 Commits

Author SHA1 Message Date
Diego Novillo 7f8af8bf91 Add support for missed and analysis optimization remarks.
Summary:
This adds two new diagnostics: -pass-remarks-missed and
-pass-remarks-analysis. They take the same values as -pass-remarks but
are intended to be triggered in different contexts.

-pass-remarks-missed is used by LLVMContext::emitOptimizationRemarkMissed,
which passes call when they tried to apply a transformation but
couldn't.

-pass-remarks-analysis is used by LLVMContext::emitOptimizationRemarkAnalysis,
which passes call when they want to inform the user about analysis
results.

The patch also:

1- Adds support in the inliner for the two new remarks and a
   test case.

2- Moves emitOptimizationRemark* functions to the llvm namespace.

3- Adds an LLVMContext argument instead of making them member functions
   of LLVMContext.

Reviewers: qcolombet

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D3682

llvm-svn: 209442
2014-05-22 14:19:46 +00:00
Manman Ren 3c44067a30 [inline cold threshold] Command line argument for inline threshold will
override the default cold threshold.

When we use command line argument to set the inline threshold, the default
cold threshold will not be used. This is in line with how we use
OptSizeThreshold. When we want a higher threshold for all functions, we
do not have to set both inline threshold and cold threshold.

llvm-svn: 207245
2014-04-25 17:34:55 +00:00
Craig Topper f40110f4d8 [C++] Use 'nullptr'. Transforms edition.
llvm-svn: 207196
2014-04-25 05:29:35 +00:00
Chandler Carruth 964daaaf19 [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all of the header #include lines, lib/Transforms/...
edition.

This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.

Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.

llvm-svn: 206844
2014-04-22 02:55:47 +00:00
NAKAMURA Takumi cd1fc4bc1b Inliner::OptimizationRemark: Fix crash in clang/test/Frontend/optimization-remark.c on some hosts, including --vg.
DebugLoc in Callsite would not live after Inliner. It should be copied before Inliner.

llvm-svn: 206459
2014-04-17 12:22:14 +00:00
Diego Novillo a9298b2297 Add support for optimization reports.
Summary:
This patch adds backend support for -Rpass=, which indicates the name
of the optimization pass that should emit remarks stating when it
made a transformation to the code.

Pass names are taken from their DEBUG_NAME definitions.

When emitting an optimization report diagnostic, the lack of debug
information causes the diagnostic to use "<unknown>:0:0" as the
location string.

This is the back end counterpart for

http://llvm-reviews.chandlerc.com/D3226

Reviewers: qcolombet

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D3227

llvm-svn: 205774
2014-04-08 16:42:34 +00:00
Chandler Carruth cdf4788401 [C++11] Add range based accessors for the Use-Def chain of a Value.
This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

llvm-svn: 203364
2014-03-09 03:16:01 +00:00
Chandler Carruth 219b89b987 [Modules] Move CallSite into the IR library where it belogs. It is
abstracting between a CallInst and an InvokeInst, both of which are IR
concepts.

llvm-svn: 202816
2014-03-04 11:01:28 +00:00
Rafael Espindola 935125126c Make DataLayout a plain object, not a pass.
Instead, have a DataLayoutPass that holds one. This will allow parts of LLVM
don't don't handle passes to also use DataLayout.

llvm-svn: 202168
2014-02-25 17:30:31 +00:00
Rafael Espindola 612886fc8c Rename a few more DataLayout variables.
llvm-svn: 201833
2014-02-21 01:53:35 +00:00
Manman Ren d461244972 Set default of inlinecold-threshold to 225.
225 is the default value of inline-threshold. This change will make sure
we have the same inlining behavior as prior to r200886.

As Chandler points out, even though we don't have code in our testing
suite that uses cold attribute, there are larger applications that do
use cold attribute.

r200886 + this commit intend to keep the same behavior as prior to r200886.
We can later on tune the inlinecold-threshold.

The main purpose of r200886 is to help performance of instrumentation based
PGO before we actually hook up inliner with analysis passes such as BPI and BFI.
For instrumentation based PGO, we try to increase inlining of hot functions and
reduce inlining of cold functions by setting inlinecold-threshold.

Another option suggested by Chandler is to use a boolean flag that controls
if we should use OptSizeThreshold for cold functions. The default value
of the boolean flag should not change the current behavior. But it gives us
less freedom in controlling inlining of cold functions.

llvm-svn: 200898
2014-02-06 01:59:22 +00:00
Manman Ren e8781b1a36 Inliner uses a smaller inline threshold for callees with cold attribute.
Added command line option inlinecold-threshold to set threshold for inlining
functions with cold attribute. Listen to the cold attribute when it would
decrease the inline threshold.

llvm-svn: 200886
2014-02-05 22:53:44 +00:00
Chandler Carruth 6378cf539f [PM] Split the CallGraph out from the ModulePass which creates the
CallGraph.

This makes the CallGraph a totally generic analysis object that is the
container for the graph data structure and the primary interface for
querying and manipulating it. The pass logic is separated into its own
class. For compatibility reasons, the pass provides wrapper methods for
most of the methods on CallGraph -- they all just forward.

This will allow the new pass manager infrastructure to provide its own
analysis pass that constructs the same CallGraph object and makes it
available. The idea is that in the new pass manager, the analysis pass's
'run' method returns a concrete analysis 'result'. Here, that result is
a 'CallGraph'. The 'run' method will typically do only minimal work,
deferring much of the work into the implementation of the result object
in order to be lazy about computing things, but when (like DomTree)
there is *some* up-front computation, the analysis does it prior to
handing the result back to the querying pass.

I know some of this is fairly ugly. I'm happy to change it around if
folks can suggest a cleaner interim state, but there is going to be some
amount of unavoidable ugliness during the transition period. The good
thing is that this is very limited and will naturally go away when the
old pass infrastructure goes away. It won't hang around to bother us
later.

Next up is the initial new-PM-style call graph analysis. =]

llvm-svn: 195722
2013-11-26 04:19:30 +00:00
Hal Finkel ec7cd26968 Fix comparisons of alloca alignment in inliner merging
Duncan pointed out a mistake in my fix in r186425 when only one of the allocas
being compared had the target-default alignment. This is essentially his
suggested solution. Thanks!

llvm-svn: 186510
2013-07-17 14:32:41 +00:00
Hal Finkel 9caa8f7ba7 When the inliner merges allocas, it must keep the larger alignment
For safety, the inliner cannot decrease the allignment on an alloca when
merging it with another.

I've included two variants of the test case for this: one with DataLayout
available, and one without. When DataLayout is not available, if only one of
the allocas uses the default alignment (getAlignment() == 0), then they cannot
be safely merged.

llvm-svn: 186425
2013-07-16 17:10:55 +00:00
Bill Wendling d154e283f2 Add the IR attribute 'sspstrong'.
SSPStrong applies a heuristic to insert stack protectors in these situations:

* A Protector is required for functions which contain an array, regardless of
  type or length.

* A Protector is required for functions which contain a structure/union which
  contains an array, regardless of type or length.  Note, there is no limit to
  the depth of nesting.

* A protector is required when the address of a local variable (i.e., stack
  based variable) is exposed. (E.g., such as through a local whose address is
  taken as part of the RHS of an assignment or a local whose address is taken as
  part of a function argument.)

This patch implements the SSPString attribute to be equivalent to
SSPRequired. This will change in a subsequent patch.

llvm-svn: 173230
2013-01-23 06:41:41 +00:00
Chandler Carruth 9fb823bbd4 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

llvm-svn: 171366
2013-01-02 11:36:10 +00:00
Bill Wendling 698e84fc4f Remove the Function::getFnAttributes method in favor of using the AttributeSet
directly.

This is in preparation for removing the use of the 'Attribute' class as a
collection of attributes. That will shift to the AttributeSet class instead.

llvm-svn: 171253
2012-12-30 10:32:01 +00:00
Chandler Carruth e40e60eed5 Make this parameter be named consistently with most other
getAnalysisUsage implementations.

llvm-svn: 171157
2012-12-27 11:17:15 +00:00
Bill Wendling 3d7b0b8ac7 Rename the 'Attributes' class to 'Attribute'. It's going to represent a single attribute in the future.
llvm-svn: 170502
2012-12-19 07:18:57 +00:00
Quentin Colombet c0dba2035a Take into account minimize size attribute in the inliner.
Better controls the inlining of functions when the caller function has MinSize attribute.
Basically, when the caller function has this attribute, we do not "force" the inlining
of callee functions carrying the InlineHint attribute (i.e., functions defined with
inline keyword)

llvm-svn: 170065
2012-12-13 01:05:25 +00:00
Chandler Carruth ed0881b2a6 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131
2012-12-03 16:50:05 +00:00
Bill Wendling f319e9905f Have 'addFnAttr' take the attribute enum value. Then have it build the attribute object and add it appropriately. No functionality change.
llvm-svn: 165595
2012-10-10 03:12:49 +00:00
Bill Wendling c9b22d735a Create enums for the different attributes.
We use the enums to query whether an Attributes object has that attribute. The
opaque layer is responsible for knowing where that specific attribute is stored.

llvm-svn: 165488
2012-10-09 07:45:08 +00:00
Micah Villmow cdfe20b97f Move TargetData to DataLayout.
llvm-svn: 165402
2012-10-08 16:38:25 +00:00
Bill Wendling 863bab689a Remove the `hasFnAttr' method from Function.
The hasFnAttr method has been replaced by querying the Attributes explicitly. No
intended functionality change.

llvm-svn: 164725
2012-09-26 21:48:26 +00:00
Nadav Rotem 97d44349c9 Fix an 80 char line limit.
llvm-svn: 163808
2012-09-13 16:27:32 +00:00
Benjamin Kramer 8bcc971174 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.

llvm-svn: 162841
2012-08-29 15:32:21 +00:00
Benjamin Kramer bde9176663 Fix typos found by http://github.com/lyda/misspell-check
llvm-svn: 157885
2012-06-02 10:20:22 +00:00
Patrik Hägglund 8a1e316c15 Fix the inliner so that the optsize function attribute don't alter the
inline threshold if the global inline threshold is lower (as for -Oz).

Reviewed by Chandler Carruth and Bill Wendling.

llvm-svn: 157323
2012-05-23 13:42:57 +00:00
Chandler Carruth 7ae90d4d2d Add two statistics to help track how we are computing the inline cost.
Yea, 'NumCallerCallersAnalyzed' isn't a great name, suggestions welcome.

llvm-svn: 154492
2012-04-11 10:15:10 +00:00
Chandler Carruth 45ae88f5fc Belatedly address some code review from Chris.
As a side note, I really dislike array_pod_sort... Do we really still
care about any STL implementations that get this so wrong? Does libc++?

llvm-svn: 153834
2012-04-01 10:41:24 +00:00
Chandler Carruth edd2826f3e Remove a bunch of empty, dead, and no-op methods from all of these
interfaces. These methods were used in the old inline cost system where
there was a persistent cache that had to be updated, invalidated, and
cleared. We're now doing more direct computations that don't require
this intricate dance. Even if we resume some level of caching, it would
almost certainly have a simpler and more narrow interface than this.

llvm-svn: 153813
2012-03-31 12:48:08 +00:00
Chandler Carruth 0539c071ea Initial commit for the rewrite of the inline cost analysis to operate
on a per-callsite walk of the called function's instructions, in
breadth-first order over the potentially reachable set of basic blocks.

This is a major shift in how inline cost analysis works to improve the
accuracy and rationality of inlining decisions. A brief outline of the
algorithm this moves to:

- Build a simplification mapping based on the callsite arguments to the
  function arguments.
- Push the entry block onto a worklist of potentially-live basic blocks.
- Pop the first block off of the *front* of the worklist (for
  breadth-first ordering) and walk its instructions using a custom
  InstVisitor.
- For each instruction's operands, re-map them based on the
  simplification mappings available for the given callsite.
- Compute any simplification possible of the instruction after
  re-mapping, and store that back int othe simplification mapping.
- Compute any bonuses, costs, or other impacts of the instruction on the
  cost metric.
- When the terminator is reached, replace any conditional value in the
  terminator with any simplifications from the mapping we have, and add
  any successors which are not proven to be dead from these
  simplifications to the worklist.
- Pop the next block off of the front of the worklist, and repeat.
- As soon as the cost of inlining exceeds the threshold for the
  callsite, stop analyzing the function in order to bound cost.

The primary goal of this algorithm is to perfectly handle dead code
paths. We do not want any code in trivially dead code paths to impact
inlining decisions. The previous metric was *extremely* flawed here, and
would always subtract the average cost of two successors of
a conditional branch when it was proven to become an unconditional
branch at the callsite. There was no handling of wildly different costs
between the two successors, which would cause inlining when the path
actually taken was too large, and no inlining when the path actually
taken was trivially simple. There was also no handling of the code
*path*, only the immediate successors. These problems vanish completely
now. See the added regression tests for the shiny new features -- we
skip recursive function calls, SROA-killing instructions, and high cost
complex CFG structures when dead at the callsite being analyzed.

Switching to this algorithm required refactoring the inline cost
interface to accept the actual threshold rather than simply returning
a single cost. The resulting interface is pretty bad, and I'm planning
to do lots of interface cleanup after this patch.

Several other refactorings fell out of this, but I've tried to minimize
them for this patch. =/ There is still more cleanup that can be done
here. Please point out anything that you see in review.

I've worked really hard to try to mirror at least the spirit of all of
the previous heuristics in the new model. It's not clear that they are
all correct any more, but I wanted to minimize the change in this single
patch, it's already a bit ridiculous. One heuristic that is *not* yet
mirrored is to allow inlining of functions with a dynamic alloca *if*
the caller has a dynamic alloca. I will add this back, but I think the
most reasonable way requires changes to the inliner itself rather than
just the cost metric, and so I've deferred this for a subsequent patch.
The test case is XFAIL-ed until then.

As mentioned in the review mail, this seems to make Clang run about 1%
to 2% faster in -O0, but makes its binary size grow by just under 4%.
I've looked into the 4% growth, and it can be fixed, but requires
changes to other parts of the inliner.

llvm-svn: 153812
2012-03-31 12:42:41 +00:00
Chandler Carruth b9e35fbc1e Make a seemingly tiny change to the inliner and fix the generated code
size bloat. Unfortunately, I expect this to disable the majority of the
benefit from r152737. I'm hopeful at least that it will fix PR12345. To
explain this requires... quite a bit of backstory I'm afraid.

TL;DR: The change in r152737 actually did The Wrong Thing for
linkonce-odr functions. This change makes it do the right thing. The
benefits we saw were simple luck, not any actual strategy. Benchmark
numbers after a mini-blog-post so that I've written down my thoughts on
why all of this works and doesn't work...

To understand what's going on here, you have to understand how the
"bottom-up" inliner actually works. There are two fundamental modes to
the inliner:

1) Standard fixed-cost bottom-up inlining. This is the mode we usually
   think about. It walks from the bottom of the CFG up to the top,
   looking at callsites, taking information about the callsite and the
   called function and computing th expected cost of inlining into that
   callsite. If the cost is under a fixed threshold, it inlines. It's
   a touch more complicated than that due to all the bonuses, weights,
   etc. Inlining the last callsite to an internal function gets higher
   weighth, etc. But essentially, this is the mode of operation.

2) Deferred bottom-up inlining (a term I just made up). This is the
   interesting mode for this patch an r152737. Initially, this works
   just like mode #1, but once we have the cost of inlining into the
   callsite, we don't just compare it with a fixed threshold. First, we
   check something else. Let's give some names to the entities at this
   point, or we'll end up hopelessly confused. We're considering
   inlining a function 'A' into its callsite within a function 'B'. We
   want to check whether 'B' has any callers, and whether it might be
   inlined into those callers. If so, we also check whether inlining 'A'
   into 'B' would block any of the opportunities for inlining 'B' into
   its callers. We take the sum of the costs of inlining 'B' into its
   callers where that inlining would be blocked by inlining 'A' into
   'B', and if that cost is less than the cost of inlining 'A' into 'B',
   then we skip inlining 'A' into 'B'.

Now, in order for #2 to make sense, we have to have some confidence that
we will actually have the opportunity to inline 'B' into its callers
when cheaper, *and* that we'll be able to revisit the decision and
inline 'A' into 'B' if that ever becomes the correct tradeoff. This
often isn't true for external functions -- we can see very few of their
callers, and we won't be able to re-consider inlining 'A' into 'B' if
'B' is external when we finally see more callers of 'B'. There are two
cases where we believe this to be true for C/C++ code: functions local
to a translation unit, and functions with an inline definition in every
translation unit which uses them. These are represented as internal
linkage and linkonce-odr (resp.) in LLVM. I enabled this logic for
linkonce-odr in r152737.

Unfortunately, when I did that, I also introduced a subtle bug. There
was an implicit assumption that the last caller of the function within
the TU was the last caller of the function in the program. We want to
bonus the last caller of the function in the program by a huge amount
for inlining because inlining that callsite has very little cost.
Unfortunately, the last caller in the TU of a linkonce-odr function is
*not* the last caller in the program, and so we don't want to apply this
bonus. If we do, we can apply it to one callsite *per-TU*. Because of
the way deferred inlining works, when it sees this bonus applied to one
callsite in the TU for 'B', it decides that inlining 'B' is of the
*utmost* importance just so we can get that final bonus. It then
proceeds to essentially force deferred inlining regardless of the actual
cost tradeoff.

The result? PR12345: code bloat, code bloat, code bloat. Another result
is getting *damn* lucky on a few benchmarks, and the over-inlining
exposing critically important optimizations. I would very much like
a list of benchmarks that regress after this change goes in, with
bitcode before and after. This will help me greatly understand what
opportunities the current cost analysis is missing.

Initial benchmark numbers look very good. WebKit files that exhibited
the worst of PR12345 went from growing to shrinking compared to Clang
with r152737 reverted.

- Bootstrapped Clang is 3% smaller with this change.
- Bootstrapped Clang -O0 over a single-source-file of lib/Lex is 4%
  faster with this change.

Please let me know about any other performance impact you see. Thanks to
Nico for reporting and urging me to actually fix, Richard Smith, Duncan
Sands, Manuel Klimek, and Benjamin Kramer for talking through the issues
today.

llvm-svn: 153506
2012-03-27 10:48:28 +00:00
Chandler Carruth 2121199241 Move the instruction simplification of callsite arguments in the inliner
to instead rely on much more generic and powerful instruction
simplification in the function cloner (and thus inliner).

This teaches the pruning function cloner to use instsimplify rather than
just the constant folder to fold values during cloning. This can
simplify a large number of things that constant folding alone cannot
begin to touch. For example, it will realize that 'or' and 'and'
instructions with certain constant operands actually become constants
regardless of what their other operand is. It also can thread back
through the caller to perform simplifications that are only possible by
looking up a few levels. In particular, GEPs and pointer testing tend to
fold much more heavily with this change.

This should (in some cases) have a positive impact on compile times with
optimizations on because the inliner itself will simply avoid cloning
a great deal of code. It already attempted to prune proven-dead code,
but now it will be use the stronger simplifications to prove more code
dead.

llvm-svn: 153403
2012-03-25 04:03:40 +00:00
Chandler Carruth d7a5f2adb0 Start removing the use of an ad-hoc 'never inline' set and instead
directly query the function information which this set was representing.
This simplifies the interface of the inline cost analysis, and makes the
always-inline pass significantly more efficient.

Previously, always-inline would first make a single set of every
function in the module *except* those marked with the always-inline
attribute. It would then query this set at every call site to see if the
function was a member of the set, and if so, refuse to inline it. This
is quite wasteful. Instead, simply check the function attribute directly
when looking at the callsite.

The normal inliner also had similar redundancy. It added every function
in the module with the noinline attribute to its set to ignore, even
though inside the cost analysis function we *already tested* the
noinline attribute and produced the same result.

The only tricky part of removing this is that we have to be able to
correctly remove only the functions inlined by the always-inline pass
when finalizing, which requires a bit of a hack. Still, much less of
a hack than the set of all non-always-inline functions was. While I was
touching this function, I switched a heavy-weight set to a vector with
sort+unique. The algorithm already had a two-phase insert and removal
pattern, we were just needlessly paying the uniquing cost on every
insert.

This probably speeds up some compiles by a small amount (-O0 compiles
with lots of always-inline, so potentially heavy libc++ users), but I've
not tried to measure it.

I believe there is no functional change here, but yell if you spot one.
None are intended.

Finally, the direction this is going in is to greatly simplify the
inline cost query interface so that we can replace its implementation
with a much more clever one. Along the way, all the APIs get simplified,
so it seems incrementally good.

llvm-svn: 152903
2012-03-16 06:10:13 +00:00
Chandler Carruth 30b8416d2c Change where we enable the heuristic that delays inlining into functions
which are small enough to themselves be inlined. Delaying in this manner
can be harmful if the function is inelligible for inlining in some (or
many) contexts as it pessimizes the code of the function itself in the
event that inlining does not eventually happen.

Previously the check was written to only do this delaying of inlining
for static functions in the hope that they could be entirely deleted and
in the knowledge that all callers of static functions will have the
opportunity to inline if it is in fact profitable. However, with C++ we
get two other important sources of functions where the definition is
always available for inlining: inline functions and templated functions.
This patch generalizes the inliner to allow linkonce-ODR (the linkage
such C++ routines receive) to also qualify for this delay-based
inlining.

Benchmarking across a range of large real-world applications shows
roughly 2% size increase across the board, but an average speedup of
about 0.5%. Some benhcmarks improved over 2%, and the 'clang' binary
itself (when bootstrapped with this feature) shows a 1% -O0 performance
improvement when run over all Sema, Lex, and Parse source code smashed
into a single file. A clean re-build of Clang+LLVM with a bootstrapped
Clang shows approximately 2% improvement, but that measurement is often
noisy.

llvm-svn: 152737
2012-03-14 20:16:41 +00:00
Chandler Carruth 595fda8466 When inlining a function and adding its inner call sites to the
candidate set for subsequent inlining, try to simplify the arguments to
the inner call site now that inlining has been performed.

The goal here is to propagate and fold constants through deeply nested
call chains. Without doing this, we loose the inliner bonus that should
be applied because the arguments don't match the exact pattern the cost
estimator uses.

Reviewed on IRC by Benjamin Kramer.

llvm-svn: 152556
2012-03-12 11:19:33 +00:00
Chad Rosier 07d37bc1ed Add support for disabling llvm.lifetime intrinsics in the AlwaysInliner. These
are optimization hints, but at -O0 we're not optimizing.  This becomes a problem
when the alwaysinline attribute is abused.
rdar://10921594

llvm-svn: 151429
2012-02-25 02:56:01 +00:00
Eli Friedman 1923a330e6 Refactor code from inlining and globalopt that checks whether a function definition is unused, and enhance it so it can tell that functions which are only used by a blockaddress are in fact dead. This probably doesn't happen much on most code, but the Linux kernel's _THIS_IP_ can trigger this issue with blockaddress. (GlobalDCE can also handle the given tescase, but we only run that at -O3.) Found while looking at PR11180.
llvm-svn: 142572
2011-10-20 05:23:42 +00:00
Chris Lattner 229907cd11 land David Blaikie's patch to de-constify Type, with a few tweaks.
llvm-svn: 135375
2011-07-18 04:54:35 +00:00
Jay Foad 1a180156b6 Remove unused STL header includes.
llvm-svn: 130068
2011-04-23 19:53:52 +00:00
Dale Johannesen a71d2cc88d Improve the accuracy of the inlining heuristic looking for the
case where a static caller is itself inlined everywhere else, and
thus may go away if it doesn't get too big due to inlining other
things into it.  If there are references to the caller other than
calls, it will not be removed; account for this.
This results in same-day completion of the case in PR8853.

llvm-svn: 122821
2011-01-04 19:01:54 +00:00
Chris Lattner fb212de06d Fix PR8735, a really terrible problem in the inliner's "alloca merging"
optimization.

Consider:
static void foo() {
  A = alloca
  ...
}

static void bar() {
  B = alloca
  ...
  call foo();
}

void main() {
  bar()
}

The inliner proceeds bottom up, but lets pretend it decides not to inline foo
into bar.  When it gets to main, it inlines bar into main(), and says "hey, I
just inlined an alloca "B" into main, lets remember that.  Then it keeps going
and finds that it now contains a call to foo.  It decides to inline foo into
main, and says "hey, foo has an alloca A, and I have an alloca B from another
inlined call site, lets reuse it".  The problem with this of course, is that 
the lifetime of A and B are nested, not disjoint.

Unfortunately I can't create a reasonable testcase for this: the one in the
PR is both huge and extremely sensitive, because you minor tweaks end up
causing foo to get inlined into bar too early.  We already have tests for the
basic alloca merging optimization and this does not break them.

llvm-svn: 120995
2010-12-06 07:52:42 +00:00
Chris Lattner 5b6a865f2e improve -debug output and comments a little.
llvm-svn: 120993
2010-12-06 07:38:40 +00:00
Jakob Stoklund Olesen 31a7eb40c1 Let the -inline-threshold command line argument take precedence over the
threshold given to createFunctionInliningPass().

Both opt -O3 and clang would silently ignore the -inline-threshold option.

llvm-svn: 118117
2010-11-02 23:40:26 +00:00
Owen Anderson a7aed18624 Reapply r110396, with fixes to appease the Linux buildbot gods.
llvm-svn: 110460
2010-08-06 18:33:48 +00:00
Owen Anderson bda59bd247 Revert r110396 to fix buildbots.
llvm-svn: 110410
2010-08-06 00:23:35 +00:00
Owen Anderson 755aceb5d0 Don't use PassInfo* as a type identifier for passes. Instead, use the address of the static
ID member as the sole unique type identifier.  Clean up APIs related to this change.

llvm-svn: 110396
2010-08-05 23:42:04 +00:00