[llvm] r259915 - CallAnalyzer::analyzeCall: change the condition back to "Cost < Threshold"
Akira Hatanaka via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 23 22:46:10 PST 2016
If Cost=0 is supposed to mean inlining has zero cost, we should make sure
Cost > 0 when the loop in InlineCost.cpp (line 1306) bails out early.
On Tue, Feb 23, 2016 at 4:26 PM, Hans Wennborg <hans at chromium.org> wrote:
> If Cost = 0 doesn't mean inlining the function has zero cost, that seems
> I think eraman knows this code. Maybe he wants to take a look?
> On Mon, Feb 22, 2016 at 9:11 PM, Akira Hatanaka via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> > Hi Hans,
> > This commit (or r252595) causes the inliner to inline functions you don't
> > want to inline (large functions) in some cases. For example, if you
> > the attached test case with "opt -inline", function "callee" will always
> > inlined even after replicating the inline-asm instruction in the last
> > block a large number of times. This happens because the loop in
> > CallAnalyzer::analyzeCall that visits the basic blocks of "callee" breaks
> > out when Cost exceeds Threshold, and when that happens Cost happens to
> be 0.
> > In this case Cost doesn't represent the true cost of the function
> > doesn't mean "inlining is free").
> > Could you take a look?
> > On Fri, Feb 5, 2016 at 12:32 PM, Hans Wennborg via llvm-commits
> > <llvm-commits at lists.llvm.org> wrote:
> >> Author: hans
> >> Date: Fri Feb 5 14:32:42 2016
> >> New Revision: 259915
> >> URL: http://llvm.org/viewvc/llvm-project?rev=259915&view=rev
> >> Log:
> >> CallAnalyzer::analyzeCall: change the condition back to "Cost <
> >> In r252595, I inadvertently changed the condition to "Cost <=
> >> which caused a significant size regression in Chrome. This commit
> >> rectifies
> >> that.
> >> Modified:
> >> llvm/trunk/lib/Analysis/InlineCost.cpp
> >> Modified: llvm/trunk/lib/Analysis/InlineCost.cpp
> >> URL:
> >> --- llvm/trunk/lib/Analysis/InlineCost.cpp (original)
> >> +++ llvm/trunk/lib/Analysis/InlineCost.cpp Fri Feb 5 14:32:42 2016
> >> @@ -1392,7 +1392,7 @@ bool CallAnalyzer::analyzeCall(CallSite
> >> else if (NumVectorInstructions <= NumInstructions / 2)
> >> Threshold -= (FiftyPercentVectorBonus - TenPercentVectorBonus);
> >> - return Cost <= std::max(0, Threshold);
> >> + return Cost < std::max(1, Threshold);
> >> }
> >> #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
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