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.
llvm-svn: 152898
correlated pairs of pointer arguments at the callsite. This is designed
to recognize the common C++ idiom of begin/end pointer pairs when the
end pointer is a constant offset from the begin pointer. With the
C-based idiom of a pointer and size, the inline cost saw the constant
size calculation, and this provides the same level of information for
begin/end pairs.
In order to propagate this information we have to search for candidate
operations on a pair of pointer function arguments (or derived from
them) which would be simplified if the pointers had a known constant
offset. Then the callsite analysis looks for such pointer pairs in the
argument list, and applies the appropriate bonus.
This helps LLVM detect that half of bounds-checked STL algorithms
(such as hash_combine_range, and some hybrid sort implementations)
disappear when inlined with a constant size input. However, it's not
a complete fix due the inaccuracy of our cost metric for constants in
general. I'm looking into that next.
Benchmarks showed no significant code size change, and very minor
performance changes. However, specific code such as hashing is showing
significantly cleaner inlining decisions.
llvm-svn: 152752
introduced. Specifically, there are cost reductions for all
constant-operand icmp instructions against an alloca, regardless of
whether the alloca will in fact be elligible for SROA. That means we
don't want to abort the icmp reduction computation when we abort the
SROA reduction computation. That in turn frees us from the need to keep
a separate worklist and defer the ICmp calculations.
Use this new-found freedom and some judicious function boundaries to
factor the innards of computing the cost factor of any given instruction
out of the loop over the instructions and into static helper functions.
This greatly simplifies the code, and hopefully makes it more clear what
is happening here.
Reviewed by Eric Christopher. There is some concern that we'd like to
ensure this doesn't get out of hand, and I plan to benchmark the effects
of this change over the next few days along with some further fixes to
the inline cost.
llvm-svn: 152368
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.
llvm-svn: 152283
savings from a pointer argument becoming an alloca. Sometimes callees will even
compare a pointer to null and then branch to an otherwise unreachable block!
Detect these cases and compute the number of saved instructions, instead of
bailing out and reporting no savings.
llvm-svn: 148941
can't handle. Also don't produce non-zero results for things which won't be
transformed by SROA at all just because we saw the loads/stores before we saw
the use of the address.
llvm-svn: 148536
call site of an intrinsic is also not an inline candidate. While here, make it
more obvious that this code ignores all intrinsics. Noticed by inspection!
llvm-svn: 147037
Some code want to check that *any* call within a function has the 'returns
twice' attribute, not just that the current function has one.
llvm-svn: 142221
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.
llvm-svn: 140919
a) Making it a per call site bonus for functions that we can move from
indirect to direct calls.
b) Reduces the bonus from 500 to 100 per call site.
c) Subtracts the size of the possible newly inlineable call from the
bonus to only add a bonus if we can inline a small function to devirtualize
it.
Also changes the bonus from a positive that's subtracted to a negative
that's added.
Fixes the remainder of rdar://8546196 by reducing the object file size
after inlining by 84%.
llvm-svn: 124916
a few loops accordingly. Should be no functional change.
This is a step for more accurate cost/benefit analysis of devirt/inlining
bonuses.
llvm-svn: 124275
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.
llvm-svn: 113535
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.
llvm-svn: 113499
on RAUW of functions, this is a correctness issue instead of a mere memory
usage problem.
No testcase until the new MergeFunctions can land.
llvm-svn: 103653
were still inlining self-recursive functions into other functions.
Inlining a recursive function into itself has the potential to
reduce recursion depth by a factor of 2, inlining a recursive
function into something else reduces recursion depth by exactly
1. Since inlining a recursive function into something else is a
weird form of loop peeling, turn this off.
The deleted testcase was added by Dale in r62107, since then
we're leaning towards not inlining recursive stuff ever. In any
case, if we like inlining recursive stuff, it should be done
within the recursive function itself to get the algorithm
recursion depth win.
llvm-svn: 102798
recursive callsites, inlining can reduce the number of calls by
exponential factors, as it does in
MultiSource/Benchmarks/Olden/treeadd. More involved heuristics
will be needed.
llvm-svn: 101969
by switching CachedFunctionInfo from a std::map to a
ValueMap (which is implemented in terms of a DenseMap).
DenseMap has different iterator invalidation semantics
than std::map.
This should hopefully fix the dragonegg builder.
llvm-svn: 101658
The Caller cost info would be reset everytime a callee was inlined. If the
caller has lots of calls and there is some mutual recursion going on, the
caller cost info could be calculated many times.
This patch reduces inliner runtime from 240s to 0.5s for a function with 20000
small function calls.
This is a more conservative version of r98089 that doesn't break the clang
test CodeGenCXX/temp-order.cpp. That test relies on rather extreme inlining
for constant folding.
llvm-svn: 98099
The Caller cost info would be reset everytime a callee was inlined. If the
caller has lots of calls and there is some mutual recursion going on, the
caller cost info could be calculated many times.
This patch reduces inliner runtime from 240s to 0.5s for a function with 20000
small function calls.
llvm-svn: 98089
After running a batch of measurements, it is clear that the inliner metrics
need some adjustments:
Own argument bonus: 20 -> 5
Outgoing argument penalty: 0 -> 5
Alloca bonus: 10 -> 5
Constant instr bonus: 7 -> 5
Dead successor bonus: 40 -> 5*(avg instrs/block)
The new cost metrics are generaly 25 points higher than before, so we may need
to move thresholds.
With this change, InlineConstants::CallPenalty becomes a political correction:
if (!isa<IntrinsicInst>(II) && !callIsSmall(CS.getCalledFunction()))
NumInsts += InlineConstants::CallPenalty + CS.arg_size();
The code size is accurately modelled by CS.arg_size(). CallPenalty is added
because calls tend to take a long time, so it may not be worth it to inline a
function with lots of calls.
All of the political corrections are in the InlineConstants namespace:
IndirectCallBonus, CallPenalty, LastCallToStaticBonus, ColdccPenalty,
NoreturnPenalty.
llvm-svn: 94615
A GEP with all constant indices is already considered free by
analyzeBasicBlock(), so don't give it an extra bonus in
CountCodeReductionForAlloca().
This patch should remove a small positive bias toward inlining functions with
variable-index GEPs, and remove a smaller negative bias from functions with
all-constant index GEPs.
llvm-svn: 94591
Functions containing indirectbr are marked NeverInline by analyzeBasicBlock(),
so there is no point in giving indirectbr special treatment in
CountCodeReductionForConstant. It is never called.
No functional change intended.
llvm-svn: 94590
Chandler Carruth