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A slight compile time optimization. If the caller knows there isn't a free register getReg() should not call getFreeReg(). 

llvm-svn: 63263
This commit is contained in:
Evan Cheng 2009-01-29 01:13:00 +00:00
parent 35a52fabf4
commit 89ba594975
1 changed files with 6 additions and 6 deletions
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12
llvm/lib/CodeGen/RegAllocLocal.cpp
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@ -220,10 +220,10 @@ namespace {
/// getReg - Find a physical register to hold the specified virtual
/// register. If all compatible physical registers are used, this method
/// spills the last used virtual register to the stack, and uses that
/// register.
///
/// register. If NoFree is true, that means the caller knows there isn't
/// a free register, do not call getFreeReg().
unsigned getReg(MachineBasicBlock &MBB, MachineInstr *MI,
unsigned VirtReg);
unsigned VirtReg, bool NoFree = false);
/// reloadVirtReg - This method transforms the specified specified virtual
/// register use to refer to a physical register. This method may do this
@ -398,11 +398,11 @@ unsigned RALocal::getFreeReg(const TargetRegisterClass *RC) {
/// the last used virtual register to the stack, and uses that register.
///
unsigned RALocal::getReg(MachineBasicBlock &MBB, MachineInstr *I,
unsigned VirtReg) {
unsigned VirtReg, bool NoFree) {
const TargetRegisterClass *RC = MF->getRegInfo().getRegClass(VirtReg);
// First check to see if we have a free register of the requested type...
unsigned PhysReg = getFreeReg(RC);
unsigned PhysReg = NoFree ? 0 : getFreeReg(RC);
// If we didn't find an unused register, scavenge one now!
if (PhysReg == 0) {
@ -498,7 +498,7 @@ MachineInstr *RALocal::reloadVirtReg(MachineBasicBlock &MBB, MachineInstr *MI,
} else { // No registers available.
// Force some poor hapless value out of the register file to
// make room for the new register, and reload it.
PhysReg = getReg(MBB, MI, VirtReg);
PhysReg = getReg(MBB, MI, VirtReg, true);
}
markVirtRegModified(VirtReg, false); // Note that this reg was just reloaded