Commit Graph

20 Commits

Author SHA1 Message Date
Chandler Carruth
4bbfbdf7d7 [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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202816 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-04 11:01:28 +00:00
Chandler Carruth
a5157e68d1 Switch CodeMetrics itself over to use TTI to determine if an instruction
is free. The whole CodeMetrics API should probably be reworked more, but
this is enough to allow deleting the duplicate code there for computing
whether an instruction is free.

All of the passes using this have been updated to pull in TTI and hand
it to the CodeMetrics stuff. Further, a dead CodeMetrics API
(analyzeFunction) is nuked for lack of users.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173036 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-21 13:04:33 +00:00
Chandler Carruth
6097e774fc Fix indentation and formatting.
This change brought to by clang-format. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173034 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-21 12:14:42 +00:00
James Molloy
67ae135759 Add a new attribute, 'noduplicate'. If a function contains a noduplicate call, the call cannot be duplicated - Jump threading, loop unrolling, loop unswitching, and loop rotation are inhibited if they would duplicate the call.
Similarly inlining of the function is inhibited, if that would duplicate the call (in particular inlining is still allowed when there is only one callsite and the function has internal linkage).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170704 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 16:04:27 +00:00
Micah Villmow
3574eca1b0 Move TargetData to DataLayout.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165402 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-08 16:38:25 +00:00
Chandler Carruth
d5003cafd6 A pile of long over-due refactorings here. There are some very, *very*
minor behavior changes with this, but nothing I have seen evidence of in
the wild or expect to be meaningful. The real goal is unifying our logic
and simplifying the interfaces. A summary of the changes follows:

- Make 'callIsSmall' actually accept a callsite so it can handle
  intrinsics, and simplify callers appropriately.
- Nuke a completely bogus declaration of 'callIsSmall' that was still
  lurking in InlineCost.h... No idea how this got missed.
- Teach the 'isInstructionFree' about the various more intelligent
  'free' heuristics that got added to the inline cost analysis during
  review and testing. This mostly surrounds int->ptr and ptr->int casts.
- Switch most of the interesting parts of the inline cost analysis that
  were essentially computing 'is this instruction free?' to use the code
  metrics routine instead. This way we won't keep duplicating logic.

All of this is motivated by the desire to allow other passes to compute
a roughly equivalent 'cost' metric for a particular basic block as the
inline cost analysis. Sadly, re-using the same analysis for both is
really messy because only the actual inline cost analysis is ever going
to go to the contortions required for simplification, SROA analysis,
etc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156140 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-04 00:58:03 +00:00
Chandler Carruth
f2286b0152 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153812 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-31 12:42:41 +00:00
Chandler Carruth
9b081d9691 Pull the implementation of the code metrics out of the inline cost
analysis implementation. The header was already separated. Also cleanup
all the comments in the header to follow a nice modern doxygen form.

There is still plenty of cruft here, but some of that will fall out in
subsequent refactorings and this was an easy step in the right
direction. No functionality changed here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152898 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-16 05:51:52 +00:00
Chandler Carruth
6f130bf368 Rotate two of the functions used to count bonuses for the inline cost
analysis to be methods on the cost analysis's function info object
instead of the code metrics object. These really are just users of the
code metrics, they're building the information for the function's
analysis.

This is the first step of growing the amount of information we collect
about a function in order to cope with pair-wise simplifications due to
allocas.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152283 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-08 02:04:19 +00:00
Rafael Espindola
3a023d3180 Fix grammar error noticed by Duncan.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147333 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-29 02:15:06 +00:00
Joerg Sonnenberger
3470693641 Allow inlining of functions with returns_twice calls, if they have the
attribute themselve.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146851 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-18 20:35:43 +00:00
Eli Friedman
5cdf0700c7 Add missing forward declarations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143717 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-04 18:29:09 +00:00
Andrew Trick
b2ab2fa524 Inlining and unrolling heuristics should be aware of free truncs.
We want heuristics to be based on accurate data, but more importantly
we don't want llvm to behave randomly. A benign trunc inserted by an
upstream pass should not cause a wild swings in optimization
level. See PR11034. It's a general problem with threshold-based
heuristics, but we can make it less bad.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140919 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-01 01:39:05 +00:00
Andrew Trick
5c655413cf whitespace
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140916 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-01 01:27:56 +00:00
Chris Lattner
0092b1142f remove the partial specialization pass. It is unmaintained and has bugs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123554 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-16 00:27:10 +00:00
Chris Lattner
c3942eb95d make this file properly self contained.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123059 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-08 08:19:49 +00:00
Kenneth Uildriks
ca52c8ba12 Start separating out code metrics into code size metrics and code performance metrics. Partial Specialization will apply the former to function specializations, and the latter to all callsites that can use a specialization, in order to decide whether to create a specialization
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116057 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-08 13:57:31 +00:00
Owen Anderson
f9a26b89f8 What the loop unroller cares about, rather than just not unrolling loops with calls, is
not unrolling loops that contain calls that would be better off getting inlined.  This mostly
comes up when an interleaved devirtualization pass has devirtualized a call which the inliner
will inline on a future pass.  Thus, rather than blocking all loops containing calls, add
a metric for "inline candidate calls" and block loops containing those instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113535 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-09 20:32:23 +00:00
Owen Anderson
082bf2a977 Refactor code-size reduction estimation methods out of InlineCostAnalyzer and into CodeMetrics. They
don't use any InlineCostAnalyzer state, and are useful for other clients who don't necessarily want to use
all of InlineCostAnalyzer's logic, some of which is fairly inlining-specific.

No intended functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113499 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-09 16:56:42 +00:00
Kenneth Uildriks
42c7d23c6d Pulled CodeMetrics out of InlineCost.h and made it a bit more general, so it can be reused from PartialSpecializationCost
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105725 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-09 15:11:37 +00:00