Coalescer should not delete copy instructions whose defs are partially dead. e.g.
%RDI<def,dead> = MOV64rr %RAX<kill>, %EDI<imp-def>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100804 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index f2ba484..9f03b5b 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -1125,6 +1125,19 @@
return Reg;
}
+/// allDefsAreDead - Return true if all the defs of this instruction are dead.
+///
+bool MachineInstr::allDefsAreDead() const {
+ for (unsigned i = 0, e = getNumOperands(); i < e; ++i) {
+ const MachineOperand &MO = getOperand(i);
+ if (!MO.isReg() || MO.isUse())
+ continue;
+ if (!MO.isDead())
+ return false;
+ }
+ return true;
+}
+
void MachineInstr::dump() const {
dbgs() << " " << *this;
}