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https://github.com/c64scene-ar/llvm-6502.git
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8e0d1c03ca
This disables malloc-specific optimization when -fno-builtin (or -ffreestanding) is specified. This has been a problem for a long time but became more severe with the recent memory builtin improvements. Since the memory builtin functions are used everywhere, this required passing TLI in many places. This means that functions that now have an optional TLI argument, like RecursivelyDeleteTriviallyDeadFunctions, won't remove dead mallocs anymore if the TLI argument is missing. I've updated most passes to do the right thing. Fixes PR13694 and probably others. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162841 91177308-0d34-0410-b5e6-96231b3b80d8
101 lines
4.0 KiB
C++
101 lines
4.0 KiB
C++
//===------ SimplifyInstructions.cpp - Remove redundant instructions ------===//
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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 is a utility pass used for testing the InstructionSimplify analysis.
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// The analysis is applied to every instruction, and if it simplifies then the
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// instruction is replaced by the simplification. If you are looking for a pass
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// that performs serious instruction folding, use the instcombine pass instead.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "instsimplify"
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#include "llvm/Function.h"
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#include "llvm/Pass.h"
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#include "llvm/Type.h"
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Analysis/Dominators.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetLibraryInfo.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/Local.h"
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using namespace llvm;
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STATISTIC(NumSimplified, "Number of redundant instructions removed");
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namespace {
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struct InstSimplifier : public FunctionPass {
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static char ID; // Pass identification, replacement for typeid
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InstSimplifier() : FunctionPass(ID) {
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initializeInstSimplifierPass(*PassRegistry::getPassRegistry());
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}
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void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesCFG();
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AU.addRequired<TargetLibraryInfo>();
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}
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/// runOnFunction - Remove instructions that simplify.
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bool runOnFunction(Function &F) {
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const DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>();
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const TargetData *TD = getAnalysisIfAvailable<TargetData>();
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const TargetLibraryInfo *TLI = &getAnalysis<TargetLibraryInfo>();
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SmallPtrSet<const Instruction*, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
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bool Changed = false;
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do {
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for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
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DE = df_end(&F.getEntryBlock()); DI != DE; ++DI)
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for (BasicBlock::iterator BI = DI->begin(), BE = DI->end(); BI != BE;) {
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Instruction *I = BI++;
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// The first time through the loop ToSimplify is empty and we try to
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// simplify all instructions. On later iterations ToSimplify is not
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// empty and we only bother simplifying instructions that are in it.
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if (!ToSimplify->empty() && !ToSimplify->count(I))
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continue;
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// Don't waste time simplifying unused instructions.
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if (!I->use_empty())
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if (Value *V = SimplifyInstruction(I, TD, TLI, DT)) {
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// Mark all uses for resimplification next time round the loop.
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for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
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UI != UE; ++UI)
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Next->insert(cast<Instruction>(*UI));
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I->replaceAllUsesWith(V);
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++NumSimplified;
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Changed = true;
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}
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Changed |= RecursivelyDeleteTriviallyDeadInstructions(I, TLI);
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}
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// Place the list of instructions to simplify on the next loop iteration
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// into ToSimplify.
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std::swap(ToSimplify, Next);
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Next->clear();
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} while (!ToSimplify->empty());
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return Changed;
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}
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};
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}
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char InstSimplifier::ID = 0;
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INITIALIZE_PASS_BEGIN(InstSimplifier, "instsimplify",
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"Remove redundant instructions", false, false)
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INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
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INITIALIZE_PASS_END(InstSimplifier, "instsimplify",
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"Remove redundant instructions", false, false)
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char &llvm::InstructionSimplifierID = InstSimplifier::ID;
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// Public interface to the simplify instructions pass.
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FunctionPass *llvm::createInstructionSimplifierPass() {
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return new InstSimplifier();
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}
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