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43cda021d9
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94615 91177308-0d34-0410-b5e6-96231b3b80d8
Analysis Opportunities:
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In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
ScalarEvolution expression for %r is this:
{1,+,3,+,2}<loop>
Outside the loop, this could be evaluated simply as (%n * %n), however
ScalarEvolution currently evaluates it as
(-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))
In addition to being much more complicated, it involves i65 arithmetic,
which is very inefficient when expanded into code.
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