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/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 0c261ba..6c68f20 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -1555,6 +1555,7 @@
BuildMI(MBB, DL, TII.get(AdjStackUp)).addImm(NumBytes).addImm(0);
// Now handle call return value (if any).
+ SmallVector<unsigned, 4> UsedRegs;
if (RetVT.getSimpleVT().SimpleTy != MVT::isVoid) {
SmallVector<CCValAssign, 16> RVLocs;
CCState CCInfo(CC, false, TM, RVLocs, I->getParent()->getContext());
@@ -1582,6 +1583,8 @@
RVLocs[0].getLocReg(), DstRC, SrcRC, DL);
assert(Emitted && "Failed to emit a copy instruction!"); Emitted=Emitted;
Emitted = true;
+ UsedRegs.push_back(RVLocs[0].getLocReg());
+
if (CopyVT != RVLocs[0].getValVT()) {
// Round the F80 the right size, which also moves to the appropriate xmm
// register. This is accomplished by storing the F80 value in memory and
@@ -1609,6 +1612,9 @@
UpdateValueMap(I, ResultReg);
}
+ // Set all unused physreg defs as dead.
+ static_cast<MachineInstr *>(MIB)->setPhysRegsDeadExcept(UsedRegs, TRI);
+
return true;
}