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The register allocator shouldn't consider allocating reserved registers. 

llvm-svn: 112728
This commit is contained in:
Jim Grosbach 2010-09-01 19:28:41 +00:00
parent 5925053b32
commit df6b67bf85
1 changed files with 7 additions and 3 deletions
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10
llvm/lib/CodeGen/RegAllocFast.cpp
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@ -113,6 +113,9 @@ namespace {
// Allocatable - vector of allocatable physical registers.
BitVector Allocatable;
// Reserved - vector of reserved physical registers.
BitVector Reserved;
// SkippedInstrs - Descriptors of instructions whose clobber list was
// ignored because all registers were spilled. It is still necessary to
// mark all the clobbered registers as used by the function.
@ -709,7 +712,7 @@ void RAFast::handleThroughOperands(MachineInstr *MI,
}
// Restore UsedInInstr to a state usable for allocating normal virtual uses.
UsedInInstr.reset();
UsedInInstr = Reserved;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || (MO.isDef() && !MO.isEarlyClobber())) continue;
@ -835,7 +838,7 @@ void RAFast::AllocateBasicBlock() {
}
// Track registers used by instruction.
UsedInInstr.reset();
UsedInInstr = Reserved;
// First scan.
// Mark physreg uses and early clobbers as used.
@ -913,7 +916,7 @@ void RAFast::AllocateBasicBlock() {
// Track registers defined by instruction - early clobbers and tied uses at
// this point.
UsedInInstr.reset();
UsedInInstr = Reserved;
if (hasEarlyClobbers) {
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
@ -1011,6 +1014,7 @@ bool RAFast::runOnMachineFunction(MachineFunction &Fn) {
UsedInInstr.resize(TRI->getNumRegs());
Allocatable = TRI->getAllocatableSet(*MF);
Reserved = TRI->getReservedRegs(*MF);
// initialize the virtual->physical register map to have a 'null'
// mapping for all virtual registers