llvm-svn: 123290

llvm-svn: 123282

For one, MachineBasicBlock::getFirstTerminator() doesn't understand what is
happening, and it also makes sense to have all control flow run through the
DBG_VALUE.

llvm-svn: 123277

These functions not longer assert when passed 0, but simply return false instead.

No functional change intended.

llvm-svn: 123155

of using a Location class with the same information.

When making a copy of a MachineOperand that was already stored in a
MachineInstr, it is necessary to clear the parent pointer on the copy. Otherwise
the register use-def lists become inconsistent.

Add MachineOperand::clearParent() to do that. An alternative would be a custom
MachineOperand copy constructor that cleared ParentMI. I didn't want to do that
because of the performance impact.

llvm-svn: 123109

Print virtual registers numbered from 0 instead of the arbitrary
FirstVirtualRegister. The first virtual register is printed as %vreg0.
TRI::NoRegister is printed as %noreg.

llvm-svn: 123107

llvm-svn: 123039

Enable live debug variables pass.

llvm-svn: 123032

llvm-svn: 120846

be emitted.

llvm-svn: 120845

llvm-svn: 120842

llvm-svn: 120841

llvm-svn: 120720

Scan the MachineFunction for DBG_VALUE instructions, and replace them with a
data structure similar to LiveIntervals. The live range of a DBG_VALUE is
determined by propagating it down the dominator tree until a new DBG_VALUE is
found. When a DBG_VALUE lives in a register, its live range is confined to the
live range of the register's value.

LiveDebugVariables runs before coalescing, so DBG_VALUEs are not artificially
extended when registers are joined.

The missing half will recreate DBG_VALUE instructions from the intervals when
register allocation is complete.

The pass is disabled by default. It can be enabled with the temporary command
line option -live-debug-variables.

llvm-svn: 120636

This analysis is going to run immediately after LiveIntervals. It will stay
alive during register allocation and keep track of user variables mentioned in
DBG_VALUE instructions.

When the register allocator is moving values between registers and the stack, it
is very hard to keep track of DBG_VALUE instructions. We usually get it wrong.
This analysis maintains a data structure that makes it easy to update DBG_VALUE
instructions.

llvm-svn: 120385