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Fix a memory smasher caught by Mac OS X's debug malloc library. We were 

incorrectly using an iterator after it was invalid.

llvm-svn: 22207
This commit is contained in:
Nate Begeman 2005-06-12 23:50:33 +00:00
parent 1609a541cd
commit 02e33b70b1
1 changed files with 19 additions and 8 deletions
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27
llvm/lib/Target/PowerPC/PowerPCBranchSelector.cpp
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@ -86,7 +86,14 @@ namespace {
for (MachineBasicBlock::iterator MBBI = MBB->begin(), EE = MBB->end();
MBBI != EE; ++MBBI) {
if (MBBI->getOpcode() == PPC::COND_BRANCH) {
// We may end up deleting the MachineInstr that MBBI points to, so
// remember its opcode now so we can refer to it after calling erase()
unsigned OpcodeToReplace = MBBI->getOpcode();
if (OpcodeToReplace == PPC::COND_BRANCH) {
MachineBasicBlock::iterator MBBJ = MBBI;
++MBBJ;
// condbranch operands:
// 0. CR0 register
// 1. bc opcode
@ -101,17 +108,21 @@ namespace {
unsigned Opcode = MBBI->getOperand(1).getImmedValue();
unsigned Inverted = PPC32InstrInfo::invertPPCBranchOpcode(Opcode);
MachineInstr *MI = MBBI;
if (Displacement >= -32768 && Displacement <= 32767) {
BuildMI(*MBB, MBBI, Opcode, 2).addReg(PPC::CR0).addMBB(trueMBB);
BuildMI(*MBB, MBBJ, Opcode, 2).addReg(PPC::CR0).addMBB(trueMBB);
} else {
BuildMI(*MBB, MBBI, Inverted, 2).addReg(PPC::CR0).addSImm(8);
BuildMI(*MBB, MBBI, PPC::B, 1).addMBB(trueMBB);
BuildMI(*MBB, MBBI, PPC::B, 1).addMBB(falseMBB);
BuildMI(*MBB, MBBJ, Inverted, 2).addReg(PPC::CR0).addSImm(8);
BuildMI(*MBB, MBBJ, PPC::B, 1).addMBB(trueMBB);
BuildMI(*MBB, MBBJ, PPC::B, 1).addMBB(falseMBB);
}
MBB->erase(MI);
// Erase the psuedo COND_BRANCH instruction, and then back up the
// iterator so that when the for loop increments it, we end up in
// the correct place rather than iterating off the end.
MBB->erase(MBBI);
MBBI = --MBBJ;
}
ByteCount += bytesForOpcode(MBBI->getOpcode());
ByteCount += bytesForOpcode(OpcodeToReplace);
}
}