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Now that we don't keep live registers across calls, there is not reason to go

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through the very long list of call-clobbered registers. We just assume all
registers are clobbered.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103930 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-05-17 02:49:18 +00:00
parent 844db9cc6f
commit 4b6bbe885d
1 changed files with 12 additions and 7 deletions
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19
lib/CodeGen/RegAllocFast.cpp
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@ -736,9 +736,20 @@ void RAFast::AllocateBasicBlock() {
UsedInInstr.set(Alias);
}
unsigned DefOpEnd = MI->getNumOperands();
if (TID.isCall()) {
// Spill all virtregs before a call. This serves two purposes: 1. If an
// exception is thrown, the landing pad is going to expect to find registers
// in their spill slots, and 2. we don't have to wade through all the
// <imp-def> operands on the call instruction.
DefOpEnd = VirtOpEnd;
DEBUG(dbgs() << " Spilling remaining registers before call.\n");
spillAll(MI);
}
// Third scan.
// Allocate defs and collect dead defs.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
for (unsigned i = 0; i != DefOpEnd; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || !MO.isDef() || !MO.getReg()) continue;
unsigned Reg = MO.getReg();
@ -758,12 +769,6 @@ void RAFast::AllocateBasicBlock() {
setPhysReg(MO, PhysReg);
}
// Spill all dirty virtregs before a call, in case of an exception.
if (TID.isCall()) {
DEBUG(dbgs() << " Spilling remaining registers before call.\n");
spillAll(MI);
}
// Process virtreg deads.
for (unsigned i = 0, e = VirtKills.size(); i != e; ++i)
killVirtReg(VirtKills[i]);