[GISel]: Don't assert when constraining RegisterOperands which are uses.
Currently we assert that only non target specific opcodes can have
missing RegisterClass constraints in the MCDesc. The backend can have
instructions with register operands but don't have RegisterClass
constraints (say using unknown_class) in which case the instruction
defining the register will constrain it.
Change the assert to only fire if a def has no regclass.
https://reviews.llvm.org/D43409
llvm-svn: 326142
diff --git a/llvm/lib/CodeGen/GlobalISel/Utils.cpp b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
index 35ad433..d75964a 100644
--- a/llvm/lib/CodeGen/GlobalISel/Utils.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
@@ -42,23 +42,25 @@
return Reg;
}
-
unsigned llvm::constrainOperandRegClass(
const MachineFunction &MF, const TargetRegisterInfo &TRI,
MachineRegisterInfo &MRI, const TargetInstrInfo &TII,
const RegisterBankInfo &RBI, MachineInstr &InsertPt, const MCInstrDesc &II,
- unsigned Reg, unsigned OpIdx) {
+ const MachineOperand &RegMO, unsigned OpIdx) {
+ unsigned Reg = RegMO.getReg();
// Assume physical registers are properly constrained.
assert(TargetRegisterInfo::isVirtualRegister(Reg) &&
"PhysReg not implemented");
const TargetRegisterClass *RegClass = TII.getRegClass(II, OpIdx, &TRI, MF);
// Some of the target independent instructions, like COPY, may not impose any
- // register class constraints on some of their operands:
+ // register class constraints on some of their operands: If it's a use, we can
+ // skip constraining as the instruction defining the register would constrain
+ // it.
if (!RegClass) {
- assert(!isTargetSpecificOpcode(II.getOpcode()) &&
- "Only target independent instructions are allowed to have operands "
- "with no register class constraints");
+ assert((!isTargetSpecificOpcode(II.getOpcode()) || RegMO.isUse()) &&
+ "Register class constraint is required unless either the "
+ "instruction is target independent or the operand is a use");
// FIXME: Just bailing out like this here could be not enough, unless we
// expect the users of this function to do the right thing for PHIs and
// COPY:
@@ -108,7 +110,7 @@
// insert COPYs if that's impossible.
// constrainOperandRegClass does that for us.
MO.setReg(constrainOperandRegClass(MF, TRI, MRI, TII, RBI, I, I.getDesc(),
- Reg, OpI));
+ MO, OpI));
// Tie uses to defs as indicated in MCInstrDesc if this hasn't already been
// done.