From: Owen Anderson Date: Mon, 12 Nov 2007 01:05:09 +0000 (+0000) Subject: As Chris and Evan pointed out, BreakCriticalMachineEdges doesn't really need X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=fe0c882e5a6ddf4e3c9f771485fdaa4672759539;p=oota-llvm.git As Chris and Evan pointed out, BreakCriticalMachineEdges doesn't really need to be a pass of its own. Instead, move it out into a helper method. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44002 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/llvm/CodeGen/BreakCriticalMachineEdge.h b/include/llvm/CodeGen/BreakCriticalMachineEdge.h new file mode 100644 index 00000000000..c02eaa784a9 --- /dev/null +++ b/include/llvm/CodeGen/BreakCriticalMachineEdge.h @@ -0,0 +1,94 @@ +//===--------- BreakCriticalMachineEdges.h - Break critical edges ---------===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by Fernando Pereira and is distributed under +// the University of Illinois Open Source License. See LICENSE.TXT for details. +// +//===---------------------------------------------------------------------===// +// +// Helper function to break a critical machine edge. +// +//===---------------------------------------------------------------------===// + +#ifndef LLVM_CODEGEN_ASMPRINTER_H +#define LLVM_CODEGEN_ASMPRINTER_H + +#include "llvm/CodeGen/MachineInstr.h" +#include "llvm/CodeGen/MachineJumpTableInfo.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Support/Compiler.h" + +namespace llvm { + +MachineBasicBlock* SplitCriticalMachineEdge(MachineBasicBlock* src, + MachineBasicBlock* dst) { + const BasicBlock* srcBB = src->getBasicBlock(); + + MachineBasicBlock* crit_mbb = new MachineBasicBlock(srcBB); + + // modify the llvm control flow graph + src->removeSuccessor(dst); + src->addSuccessor(crit_mbb); + crit_mbb->addSuccessor(dst); + + // insert the new block into the machine function. + src->getParent()->getBasicBlockList().insert(src->getParent()->end(), + crit_mbb); + + // insert a unconditional branch linking the new block to dst + const TargetMachine& TM = src->getParent()->getTarget(); + const TargetInstrInfo* TII = TM.getInstrInfo(); + std::vector emptyConditions; + TII->InsertBranch(*crit_mbb, dst, (MachineBasicBlock*)0, emptyConditions); + + // modify every branch in src that points to dst to point to the new + // machine basic block instead: + MachineBasicBlock::iterator mii = src->end(); + bool found_branch = false; + while (mii != src->begin()) { + mii--; + // if there are no more branches, finish the loop + if (!TII->isTerminatorInstr(mii->getOpcode())) { + break; + } + + // Scan the operands of this branch, replacing any uses of dst with + // crit_mbb. + for (unsigned i = 0, e = mii->getNumOperands(); i != e; ++i) { + MachineOperand & mo = mii->getOperand(i); + if (mo.isMachineBasicBlock() && + mo.getMachineBasicBlock() == dst) { + found_branch = true; + mo.setMachineBasicBlock(crit_mbb); + } + } + } + + // TODO: This is tentative. It may be necessary to fix this code. Maybe + // I am inserting too many gotos, but I am trusting that the asm printer + // will optimize the unnecessary gotos. + if(!found_branch) { + TII->InsertBranch(*src, crit_mbb, (MachineBasicBlock*)0, emptyConditions); + } + + /// Change all the phi functions in dst, so that the incoming block be + /// crit_mbb, instead of src + for(mii = dst->begin(); mii != dst->end(); mii++) { + /// the first instructions are always phi functions. + if(mii->getOpcode() != TargetInstrInfo::PHI) + break; + + for (unsigned u = 0; u != mii->getNumOperands(); ++u) + if (mii->getOperand(u).isMachineBasicBlock() && + mii->getOperand(u).getMachineBasicBlock() == src) + mii->getOperand(u).setMachineBasicBlock(crit_mbb); + } + + return crit_mbb; +} + +} + +#endif diff --git a/include/llvm/CodeGen/Passes.h b/include/llvm/CodeGen/Passes.h index 89e8ba9b37a..5e93525ab47 100644 --- a/include/llvm/CodeGen/Passes.h +++ b/include/llvm/CodeGen/Passes.h @@ -58,10 +58,6 @@ namespace llvm { /// extern const PassInfo *SimpleRegisterCoalescingID; - /// BreakCriticalMachineEdges pass. Breaks critical edges between - /// machine basic blocks. - extern const PassInfo *BreakCriticalMachineEdgesID; - /// TwoAddressInstruction pass - This pass reduces two-address instructions to /// use two operands. This destroys SSA information but it is desired by /// register allocators. diff --git a/lib/CodeGen/BreakCriticalMachineEdges.cpp b/lib/CodeGen/BreakCriticalMachineEdges.cpp deleted file mode 100644 index 21d9dbbd6c3..00000000000 --- a/lib/CodeGen/BreakCriticalMachineEdges.cpp +++ /dev/null @@ -1,131 +0,0 @@ -//===----------- BreakCriticalMachineEdges - Break critical edges ---------===// -// -// The LLVM Compiler Infrastructure -// -// This file was developed by Fernando Pereira and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. -// -//===---------------------------------------------------------------------===// -// -// Break all of the critical edges in the CFG by inserting a dummy basic block. -// This pass may be "required" by passes that cannot deal with critical edges. -// Notice that this pass invalidates the CFG, because the same BasicBlock is -// used as parameter for the src MachineBasicBlock and the new dummy -// MachineBasicBlock. -// -//===---------------------------------------------------------------------===// - -#include "llvm/CodeGen/Passes.h" -#include "llvm/CodeGen/MachineFunctionPass.h" -#include "llvm/CodeGen/MachineInstr.h" -#include "llvm/CodeGen/MachineJumpTableInfo.h" -#include "llvm/Target/TargetInstrInfo.h" -#include "llvm/Target/TargetMachine.h" -#include "llvm/ADT/Statistic.h" -#include "llvm/Support/Compiler.h" - -using namespace llvm; - -namespace { - struct VISIBILITY_HIDDEN BreakCriticalMachineEdges : - public MachineFunctionPass { - static char ID; // Pass identification - BreakCriticalMachineEdges() : MachineFunctionPass((intptr_t)&ID) {} - - bool runOnMachineFunction(MachineFunction& Fn); - void splitCriticalEdge(MachineBasicBlock* A, MachineBasicBlock* B); - }; - - char BreakCriticalMachineEdges::ID = 0; - RegisterPass X("critical-machine-edges", - "Break critical machine code edges"); -} - -const PassInfo *llvm::BreakCriticalMachineEdgesID = X.getPassInfo(); - -void BreakCriticalMachineEdges::splitCriticalEdge(MachineBasicBlock* src, - MachineBasicBlock* dst) { - const BasicBlock* srcBB = src->getBasicBlock(); - - MachineBasicBlock* crit_mbb = new MachineBasicBlock(srcBB); - - // modify the llvm control flow graph - src->removeSuccessor(dst); - src->addSuccessor(crit_mbb); - crit_mbb->addSuccessor(dst); - - // insert the new block into the machine function. - src->getParent()->getBasicBlockList().insert(src->getParent()->end(), - crit_mbb); - - // insert a unconditional branch linking the new block to dst - const TargetMachine& TM = src->getParent()->getTarget(); - const TargetInstrInfo* TII = TM.getInstrInfo(); - std::vector emptyConditions; - TII->InsertBranch(*crit_mbb, dst, (MachineBasicBlock*)0, emptyConditions); - - // modify every branch in src that points to dst to point to the new - // machine basic block instead: - MachineBasicBlock::iterator mii = src->end(); - bool found_branch = false; - while (mii != src->begin()) { - mii--; - // if there are no more branches, finish the loop - if (!TII->isTerminatorInstr(mii->getOpcode())) { - break; - } - - // Scan the operands of this branch, replacing any uses of dst with - // crit_mbb. - for (unsigned i = 0, e = mii->getNumOperands(); i != e; ++i) { - MachineOperand & mo = mii->getOperand(i); - if (mo.isMachineBasicBlock() && - mo.getMachineBasicBlock() == dst) { - found_branch = true; - mo.setMachineBasicBlock(crit_mbb); - } - } - } - - // TODO: This is tentative. It may be necessary to fix this code. Maybe - // I am inserting too many gotos, but I am trusting that the asm printer - // will optimize the unnecessary gotos. - if(!found_branch) { - TII->InsertBranch(*src, crit_mbb, (MachineBasicBlock*)0, emptyConditions); - } - - /// Change all the phi functions in dst, so that the incoming block be - /// crit_mbb, instead of src - for(mii = dst->begin(); mii != dst->end(); mii++) { - /// the first instructions are always phi functions. - if(mii->getOpcode() != TargetInstrInfo::PHI) - break; - - for (unsigned u = 0; u != mii->getNumOperands(); ++u) - if (mii->getOperand(u).isMachineBasicBlock() && - mii->getOperand(u).getMachineBasicBlock() == src) - mii->getOperand(u).setMachineBasicBlock(crit_mbb); - } -} - -bool BreakCriticalMachineEdges::runOnMachineFunction(MachineFunction& F) { - std::vector SourceBlocks; - std::vector DestBlocks; - - for(MachineFunction::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) { - for(MachineBasicBlock::succ_iterator SI = FI->succ_begin(), - SE = FI->succ_end(); SI != SE; ++SI) { - // predecessor with multiple successors, successor with multiple - // predecessors. - if (FI->succ_size() > 1 && (*SI)->pred_size() > 1) { - SourceBlocks.push_back(FI); - DestBlocks.push_back(*SI); - } - } - } - - for(unsigned u = 0; u < SourceBlocks.size(); u++) - splitCriticalEdge(SourceBlocks[u], DestBlocks[u]); - - return false; -} diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp index 5f84b586cb8..f64186e8e8c 100644 --- a/lib/CodeGen/StrongPHIElimination.cpp +++ b/lib/CodeGen/StrongPHIElimination.cpp @@ -21,6 +21,7 @@ #define DEBUG_TYPE "strongphielim" #include "llvm/CodeGen/Passes.h" +#include "llvm/CodeGen/BreakCriticalMachineEdge.h" #include "llvm/CodeGen/LiveVariables.h" #include "llvm/CodeGen/MachineDominators.h" #include "llvm/CodeGen/MachineFunctionPass.h" diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp index defd6ce6fbe..b8d38dc229e 100644 --- a/lib/CodeGen/TwoAddressInstructionPass.cpp +++ b/lib/CodeGen/TwoAddressInstructionPass.cpp @@ -70,7 +70,6 @@ void TwoAddressInstructionPass::getAnalysisUsage(AnalysisUsage &AU) const { AU.addRequired(); AU.addPreserved(); AU.addPreservedID(PHIEliminationID); - AU.addPreservedID(BreakCriticalMachineEdgesID); MachineFunctionPass::getAnalysisUsage(AU); }