llvm-6502/lib/Transforms/IPO/InlineSimple.cpp
Hal Finkel 3666e7f4c1 Add an Assumption-Tracking Pass
This adds an immutable pass, AssumptionTracker, which keeps a cache of
@llvm.assume call instructions within a module. It uses callback value handles
to keep stale functions and intrinsics out of the map, and it relies on any
code that creates new @llvm.assume calls to notify it of the new instructions.
The benefit is that code needing to find @llvm.assume intrinsics can do so
directly, without scanning the function, thus allowing the cost of @llvm.assume
handling to be negligible when none are present.

The current design is intended to be lightweight. We don't keep track of
anything until we need a list of assumptions in some function. The first time
this happens, we scan the function. After that, we add/remove @llvm.assume
calls from the cache in response to registration calls and ValueHandle
callbacks.

There are no new direct test cases for this pass, but because it calls it
validation function upon module finalization, we'll pick up detectable
inconsistencies from the other tests that touch @llvm.assume calls.

This pass will be used by follow-up commits that make use of @llvm.assume.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217334 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 12:44:26 +00:00

106 lines
3.2 KiB
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//===- InlineSimple.cpp - Code to perform simple function inlining --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements bottom-up inlining of functions into callees.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionTracker.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/InlineCost.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Transforms/IPO/InlinerPass.h"
using namespace llvm;
#define DEBUG_TYPE "inline"
namespace {
/// \brief Actual inliner pass implementation.
///
/// The common implementation of the inlining logic is shared between this
/// inliner pass and the always inliner pass. The two passes use different cost
/// analyses to determine when to inline.
class SimpleInliner : public Inliner {
InlineCostAnalysis *ICA;
public:
SimpleInliner() : Inliner(ID), ICA(nullptr) {
initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
}
SimpleInliner(int Threshold)
: Inliner(ID, Threshold, /*InsertLifetime*/ true), ICA(nullptr) {
initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
}
static char ID; // Pass identification, replacement for typeid
InlineCost getInlineCost(CallSite CS) override {
return ICA->getInlineCost(CS, getInlineThreshold(CS));
}
bool runOnSCC(CallGraphSCC &SCC) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
};
static int computeThresholdFromOptLevels(unsigned OptLevel,
unsigned SizeOptLevel) {
if (OptLevel > 2)
return 275;
if (SizeOptLevel == 1) // -Os
return 75;
if (SizeOptLevel == 2) // -Oz
return 25;
return 225;
}
} // end anonymous namespace
char SimpleInliner::ID = 0;
INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
"Function Integration/Inlining", false, false)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
INITIALIZE_PASS_DEPENDENCY(InlineCostAnalysis)
INITIALIZE_PASS_END(SimpleInliner, "inline",
"Function Integration/Inlining", false, false)
Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
Pass *llvm::createFunctionInliningPass(int Threshold) {
return new SimpleInliner(Threshold);
}
Pass *llvm::createFunctionInliningPass(unsigned OptLevel,
unsigned SizeOptLevel) {
return new SimpleInliner(
computeThresholdFromOptLevels(OptLevel, SizeOptLevel));
}
bool SimpleInliner::runOnSCC(CallGraphSCC &SCC) {
ICA = &getAnalysis<InlineCostAnalysis>();
return Inliner::runOnSCC(SCC);
}
void SimpleInliner::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<InlineCostAnalysis>();
Inliner::getAnalysisUsage(AU);
}