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[BranchFolding] Replace custom MachineInstr with MachineInstrExpressionTrait 

While the hash functions are subtly different it shouldn't have an
impact. Instructions are checked with isIdenticalTo later.

llvm-svn: 240040
This commit is contained in:
Benjamin Kramer 2015-06-18 20:00:03 +00:00
parent c65d43e649
commit 8985b32e76
1 changed files with 6 additions and 46 deletions
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52
llvm/lib/CodeGen/BranchFolding.cpp
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@ -264,54 +264,14 @@ bool BranchFolder::OptimizeFunction(MachineFunction &MF,
// Tail Merging of Blocks
//===----------------------------------------------------------------------===//
/// HashMachineInstr - Compute a hash value for MI and its operands.
static unsigned HashMachineInstr(const MachineInstr *MI) {
unsigned Hash = MI->getOpcode();
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &Op = MI->getOperand(i);
// Merge in bits from the operand if easy.
unsigned OperandHash = 0;
switch (Op.getType()) {
case MachineOperand::MO_Register: OperandHash = Op.getReg(); break;
case MachineOperand::MO_Immediate: OperandHash = Op.getImm(); break;
case MachineOperand::MO_MachineBasicBlock:
OperandHash = Op.getMBB()->getNumber();
break;
case MachineOperand::MO_FrameIndex:
case MachineOperand::MO_ConstantPoolIndex:
case MachineOperand::MO_JumpTableIndex:
OperandHash = Op.getIndex();
break;
case MachineOperand::MO_GlobalAddress:
case MachineOperand::MO_ExternalSymbol:
// Global address / external symbol are too hard, don't bother, but do
// pull in the offset.
OperandHash = Op.getOffset();
break;
default: break;
}
Hash += ((OperandHash << 3) | Op.getType()) << (i&31);
}
return Hash;
}
/// HashEndOfMBB - Hash the last instruction in the MBB.
static unsigned HashEndOfMBB(const MachineBasicBlock *MBB) {
MachineBasicBlock::const_iterator I = MBB->end();
if (I == MBB->begin())
return 0; // Empty MBB.
--I;
// Skip debug info so it will not affect codegen.
while (I->isDebugValue()) {
if (I==MBB->begin())
return 0; // MBB empty except for debug info.
--I;
}
return HashMachineInstr(I);
auto LastInst = MBB->getLastNonDebugInstr();
if (LastInst == MBB->end())
return 0;
// Hash the instruction and all operands. MachineInstrExpressionTrait ignores
// vreg defs when computing the hash but we're post-regalloc here.
return MachineInstrExpressionTrait::getHashValue(LastInst);
}
/// ComputeCommonTailLength - Given two machine basic blocks, compute the number