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d5003cafd6
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
96 lines
3.3 KiB
C++
96 lines
3.3 KiB
C++
//===- CodeMetrics.h - Code cost measurements -------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements various weight measurements for code, helping
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// the Inliner and other passes decide whether to duplicate its contents.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_CODEMETRICS_H
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#define LLVM_ANALYSIS_CODEMETRICS_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/Support/CallSite.h"
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namespace llvm {
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class BasicBlock;
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class Function;
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class Instruction;
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class TargetData;
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class Value;
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/// \brief Check whether an instruction is likely to be "free" when lowered.
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bool isInstructionFree(const Instruction *I, const TargetData *TD = 0);
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/// \brief Check whether a call will lower to something small.
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///
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/// This tests checks whether this callsite will lower to something
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/// significantly cheaper than a traditional call, often a single
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/// instruction. Note that if isInstructionFree(CS.getInstruction()) would
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/// return true, so will this function.
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bool callIsSmall(ImmutableCallSite CS);
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/// \brief Utility to calculate the size and a few similar metrics for a set
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/// of basic blocks.
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struct CodeMetrics {
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/// \brief True if this function contains a call to setjmp or other functions
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/// with attribute "returns twice" without having the attribute itself.
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bool exposesReturnsTwice;
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/// \brief True if this function calls itself.
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bool isRecursive;
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/// \brief True if this function contains one or more indirect branches.
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bool containsIndirectBr;
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/// \brief True if this function calls alloca (in the C sense).
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bool usesDynamicAlloca;
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/// \brief Number of instructions in the analyzed blocks.
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unsigned NumInsts;
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/// \brief Number of analyzed blocks.
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unsigned NumBlocks;
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/// \brief Keeps track of basic block code size estimates.
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DenseMap<const BasicBlock *, unsigned> NumBBInsts;
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/// \brief Keep track of the number of calls to 'big' functions.
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unsigned NumCalls;
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/// \brief The number of calls to internal functions with a single caller.
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///
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/// These are likely targets for future inlining, likely exposed by
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/// interleaved devirtualization.
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unsigned NumInlineCandidates;
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/// \brief How many instructions produce vector values.
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///
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/// The inliner is more aggressive with inlining vector kernels.
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unsigned NumVectorInsts;
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/// \brief How many 'ret' instructions the blocks contain.
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unsigned NumRets;
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CodeMetrics() : exposesReturnsTwice(false), isRecursive(false),
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containsIndirectBr(false), usesDynamicAlloca(false),
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NumInsts(0), NumBlocks(0), NumCalls(0),
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NumInlineCandidates(0), NumVectorInsts(0),
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NumRets(0) {}
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/// \brief Add information about a block to the current state.
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void analyzeBasicBlock(const BasicBlock *BB, const TargetData *TD = 0);
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/// \brief Add information about a function to the current state.
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void analyzeFunction(Function *F, const TargetData *TD = 0);
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};
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}
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#endif
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