Don't perform expensive queries checking for super and sub registers when we know that there aren't any.
This speed up LiveVariables on instcombine at -O0 -g from 0.3855s to 0.3503s. Look for more improvements in this area soon!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52804 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index e008c9a..5da6a31 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -780,6 +780,7 @@
const TargetRegisterInfo *RegInfo,
bool AddIfNotFound) {
bool isPhysReg = TargetRegisterInfo::isPhysicalRegister(IncomingReg);
+ bool hasAliases = isPhysReg && RegInfo->getAliasSet(IncomingReg) == 0;
bool Found = false;
SmallVector<unsigned,4> DeadOps;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
@@ -790,7 +791,7 @@
if (Reg == IncomingReg) {
MO.setIsDead();
Found = true;
- } else if (isPhysReg && MO.isDead() &&
+ } else if (hasAliases && MO.isDead() &&
TargetRegisterInfo::isPhysicalRegister(Reg)) {
// There exists a super-register that's marked dead.
if (RegInfo->isSuperRegister(IncomingReg, Reg))