Teach regular and fast isel to set dead flags on unused implicit defs
on calls and similar instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106353 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 7e60c32..9e7d392 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -1461,6 +1461,25 @@
true /*IsImp*/));
}
+void MachineInstr::setPhysRegsDeadExcept(const SmallVectorImpl<unsigned> &UsedRegs,
+ const TargetRegisterInfo &TRI) {
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = getOperand(i);
+ if (!MO.isReg() || !MO.isDef()) continue;
+ unsigned Reg = MO.getReg();
+ if (Reg == 0) continue;
+ bool Dead = true;
+ for (SmallVectorImpl<unsigned>::const_iterator I = UsedRegs.begin(),
+ E = UsedRegs.end(); I != E; ++I)
+ if (TRI.regsOverlap(*I, Reg)) {
+ Dead = false;
+ break;
+ }
+ // If there are no uses, including partial uses, the def is dead.
+ if (Dead) MO.setIsDead();
+ }
+}
+
unsigned
MachineInstrExpressionTrait::getHashValue(const MachineInstr* const &MI) {
unsigned Hash = MI->getOpcode() * 37;