Avoid iterating every operand of an instruction in StrongPHIElimination, since
we are only interested in the defs when discovering interferences.
This is a 28% speedup running StrongPHIElimination on 403.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122596 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp
index c1a76a6..f84fdbe 100644
--- a/lib/CodeGen/StrongPHIElimination.cpp
+++ b/lib/CodeGen/StrongPHIElimination.cpp
@@ -471,10 +471,9 @@
DenseMap<unsigned, unsigned>& ImmediateDominatingParent) {
for (MachineBasicBlock::iterator BBI = MBB.begin(), BBE = MBB.end();
BBI != BBE; ++BBI) {
- for (unsigned i = 0, e = BBI->getNumOperands(); i != e; ++i) {
- MachineOperand& MO = BBI->getOperand(i);
- if (!MO.isReg() || !MO.isDef())
- continue;
+ for (MachineInstr::const_mop_iterator I = BBI->operands_begin(),
+ E = BBI->operands_end(); I != E && I->isReg() && I->isDef(); ++I) {
+ const MachineOperand& MO = *I;
unsigned DestReg = MO.getReg();
if (!DestReg || !TargetRegisterInfo::isVirtualRegister(DestReg))