Make MachineRegisterInfo::getVRegDef more efficient by aiming the keep the def of the vreg at the start of the list, so the list doesn't need to be traversed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45483 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-01-01 21:08:22 +00:00
parent e138b3dd1f
commit 80fe5311b5

View File

@ -42,17 +42,23 @@ void MachineOperand::AddRegOperandToRegInfo(MachineRegisterInfo *RegInfo) {
}
// Otherwise, add this operand to the head of the registers use/def list.
MachineOperand *&Head = RegInfo->getRegUseDefListHead(getReg());
MachineOperand **Head = &RegInfo->getRegUseDefListHead(getReg());
Contents.Reg.Next = Head;
// For SSA values, we prefer to keep the definition at the start of the list.
// we do this by skipping over the definition if it is at the head of the
// list.
if (*Head && (*Head)->isDef())
Head = &(*Head)->Contents.Reg.Next;
Contents.Reg.Next = *Head;
if (Contents.Reg.Next) {
assert(getReg() == Contents.Reg.Next->getReg() &&
"Different regs on the same list!");
Contents.Reg.Next->Contents.Reg.Prev = &Contents.Reg.Next;
}
Contents.Reg.Prev = &Head;
Head = this;
Contents.Reg.Prev = Head;
*Head = this;
}
void MachineOperand::setReg(unsigned Reg) {