[llvm-commits] [llvm] r98401 - in /llvm/trunk: include/llvm/Analysis/InlineCost.h lib/Analysis/InlineCost.cpp

[Jakob Stoklund Olesen]

On Mar 12, 2010, at 4:10 PM, Devang Patel wrote:

> Author: dpatel
> Date: Fri Mar 12 18:10:20 2010
> New Revision: 98401
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=98401&view=rev
> Log:
> Do not overestimate code size reduction in presense of debug info.
> Use CodeMetrics.analyzeBasicBlock() to estimate BB size.
> 
> Modified:
>    llvm/trunk/include/llvm/Analysis/InlineCost.h
>    llvm/trunk/lib/Analysis/InlineCost.cpp
> 
> Modified: llvm/trunk/include/llvm/Analysis/InlineCost.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/InlineCost.h?rev=98401&r1=98400&r2=98401&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Analysis/InlineCost.h (original)
> +++ llvm/trunk/include/llvm/Analysis/InlineCost.h Fri Mar 12 18:10:20 2010
> @@ -18,6 +18,7 @@
> #include <climits>
> #include <map>
> #include <vector>
> +#include "llvm/ADT/DenseMap.h"
> 
> namespace llvm {
> 
> @@ -42,6 +43,9 @@
>     /// is used to estimate the code size cost of inlining it.
>     unsigned NumInsts, NumBlocks;
> 
> +    /// NumBBInsts - Keeps track of basic block code size estimates.
> +    DenseMap<const BasicBlock *, unsigned> NumBBInsts;
> +
>     /// NumCalls - Keep track of the number of calls to 'big' functions.
>     unsigned NumCalls;
> 
> @@ -148,7 +152,7 @@
>       /// CountCodeReductionForConstant - Figure out an approximation for how
>       /// many instructions will be constant folded if the specified value is
>       /// constant.
> -      unsigned CountCodeReductionForConstant(Value *V);
> +      unsigned CountCodeReductionForConstant(Value *V, CodeMetrics &M);

The extra argument is not necessary since FunctionInfo already has a Metrics member.

> 
>       /// CountCodeReductionForAlloca - Figure out an approximation of how much
>       /// smaller the function will be if it is inlined into a context where an
> 
> Modified: llvm/trunk/lib/Analysis/InlineCost.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InlineCost.cpp?rev=98401&r1=98400&r2=98401&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Analysis/InlineCost.cpp (original)
> +++ llvm/trunk/lib/Analysis/InlineCost.cpp Fri Mar 12 18:10:20 2010
> @@ -22,7 +22,7 @@
> // instructions will be constant folded if the specified value is constant.
> //
> unsigned InlineCostAnalyzer::FunctionInfo::
> -         CountCodeReductionForConstant(Value *V) {
> +CountCodeReductionForConstant(Value *V, CodeMetrics &Metrics) {
>   unsigned Reduction = 0;
>   for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI)
>     if (isa<BranchInst>(*UI) || isa<SwitchInst>(*UI)) {
> @@ -31,7 +31,7 @@
>       const unsigned NumSucc = TI.getNumSuccessors();
>       unsigned Instrs = 0;
>       for (unsigned I = 0; I != NumSucc; ++I)
> -        Instrs += TI.getSuccessor(I)->size();
> +        Instrs += Metrics.NumBBInsts[TI.getSuccessor(I)];
>       // We don't know which blocks will be eliminated, so use the average size.
>       Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc;
>     } else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
> @@ -71,7 +71,7 @@
> 
>         // And any other instructions that use it which become constants
>         // themselves.
> -        Reduction += CountCodeReductionForConstant(&Inst);
> +        Reduction += CountCodeReductionForConstant(&Inst, Metrics);
>       }
>     }
> 
> @@ -142,7 +142,7 @@
> /// from the specified block.
> void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB) {
>   ++NumBlocks;
> -
> +  unsigned NumInstsInThisBB = 0;
>   for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
>        II != E; ++II) {
>     if (isa<PHINode>(II)) continue;           // PHI nodes don't count.
> @@ -196,6 +196,7 @@
>     }
> 
>     ++NumInsts;
> +    ++NumInstsInThisBB;

I think you should also include 'NumInsts += InlineConstants::CallPenalty + CS.arg_size();' for consistency.

/jakob