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In hexagon convertToHardwareLoop, don't deref end() iterator 

In particular, check if MachineBasicBlock::iterator is end() before
using it to call getDebugLoc();

See also this thread on llvm-commits:
   http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20121112/155914.html

llvm-svn: 169634
This commit is contained in:
Matthew Curtis 2012-12-07 21:03:15 +00:00
parent 89660bf795
commit 7a93811e8b
2 changed files with 15 additions and 8 deletions
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21
llvm/lib/Target/Hexagon/HexagonHardwareLoops.cpp
View File

@ -461,6 +461,9 @@ bool HexagonHardwareLoops::convertToHardwareLoop(MachineLoop *L) {
return false;
}
MachineBasicBlock::iterator LastI = LastMBB->getFirstTerminator();
if (LastI == LastMBB->end()) {
return false;
}
// Determine the loop start.
MachineBasicBlock *LoopStart = L->getTopBlock();
@ -478,6 +481,9 @@ bool HexagonHardwareLoops::convertToHardwareLoop(MachineLoop *L) {
// Convert the loop to a hardware loop
DEBUG(dbgs() << "Change to hardware loop at "; L->dump());
DebugLoc InsertPosDL;
if (InsertPos != Preheader->end())
InsertPosDL = InsertPos->getDebugLoc();
if (TripCount->isReg()) {
// Create a copy of the loop count register.
@ -485,23 +491,23 @@ bool HexagonHardwareLoops::convertToHardwareLoop(MachineLoop *L) {
const TargetRegisterClass *RC =
MF->getRegInfo().getRegClass(TripCount->getReg());
unsigned CountReg = MF->getRegInfo().createVirtualRegister(RC);
BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
BuildMI(*Preheader, InsertPos, InsertPosDL,
TII->get(TargetOpcode::COPY), CountReg).addReg(TripCount->getReg());
if (TripCount->isNeg()) {
unsigned CountReg1 = CountReg;
CountReg = MF->getRegInfo().createVirtualRegister(RC);
BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
BuildMI(*Preheader, InsertPos, InsertPosDL,
TII->get(Hexagon::NEG), CountReg).addReg(CountReg1);
}
// Add the Loop instruction to the beginning of the loop.
BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
BuildMI(*Preheader, InsertPos, InsertPosDL,
TII->get(Hexagon::LOOP0_r)).addMBB(LoopStart).addReg(CountReg);
} else {
assert(TripCount->isImm() && "Expecting immedate vaule for trip count");
// Add the Loop immediate instruction to the beginning of the loop.
int64_t CountImm = TripCount->getImm();
BuildMI(*Preheader, InsertPos, InsertPos->getDebugLoc(),
BuildMI(*Preheader, InsertPos, InsertPosDL,
TII->get(Hexagon::LOOP0_i)).addMBB(LoopStart).addImm(CountImm);
}
@ -514,8 +520,9 @@ bool HexagonHardwareLoops::convertToHardwareLoop(MachineLoop *L) {
BlockAddress::get(const_cast<BasicBlock *>(LoopStart->getBasicBlock()));
// Replace the loop branch with an endloop instruction.
DebugLoc dl = LastI->getDebugLoc();
BuildMI(*LastMBB, LastI, dl, TII->get(Hexagon::ENDLOOP0)).addMBB(LoopStart);
DebugLoc LastIDL = LastI->getDebugLoc();
BuildMI(*LastMBB, LastI, LastIDL,
TII->get(Hexagon::ENDLOOP0)).addMBB(LoopStart);
// The loop ends with either:
// - a conditional branch followed by an unconditional branch, or
@ -530,7 +537,7 @@ bool HexagonHardwareLoops::convertToHardwareLoop(MachineLoop *L) {
TII->RemoveBranch(*LastMBB);
}
SmallVector<MachineOperand, 0> Cond;
TII->InsertBranch(*LastMBB, BranchTarget, 0, Cond, dl);
TII->InsertBranch(*LastMBB, BranchTarget, 0, Cond, LastIDL);
}
} else {
// Conditional branch to loop start; just delete it.

2
llvm/test/CodeGen/Hexagon/postinc-load.ll
View File

@ -1,4 +1,4 @@
; RUN: true || llc -march=hexagon -mcpu=hexagonv4 < %s | FileCheck %s
; RUN: llc -march=hexagon -mcpu=hexagonv4 < %s | FileCheck %s
; Check that post-increment load instructions are being generated.
; CHECK: r{{[0-9]+}}{{ *}}={{ *}}memw(r{{[0-9]+}}{{ *}}++{{ *}}#4{{ *}})