CodeEmitterGen produce wrong values in generated function getBinaryCodeForInstr(...)

[llvmbot]

Bugzilla Link	2827
Resolution	FIXED
Resolved on	Nov 07, 2018 00:22
Version	2.3
OS	All
Reporter	LLVM Bugzilla Contributor

Extended Description

In generated XXXCodeEmitter::getBinaryCodeForInstr(MachineInstr &MI) tablegen produce wrong values, if a 32 bit instruction operand is used. So the generated code looks like this:
case sharc::PUSHGAddr: {
// op: registerINumber
op = getMachineOpValue(MI, MI.getOperand(0));
Value |= (op & 7U) << 41;
// op: registerMNumber
op = getMachineOpValue(MI, MI.getOperand(1));
Value |= (op & 7U) << 38;
// op: immediateData
op = getMachineOpValue(MI, MI.getOperand(2));
Value |= op & 0U; // <<<<<<<<<<<<<<<<<<<<<<<<<<<< BUG.
break;
}

The reason for that is that in CodeGenEmitterGen.cpp line 190:
unsigned opMask = (1 << N) - 1;
If N=32, than the opMask is zero, instead of 0xffffffff

Solution:
CodeGenEmitterGen.cpp line 190:
unsigned opMask = (1ULL << N) - 1;

[lattner]

Fixed with a slightly different approach, please verify that this works for you:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20080929/068087.html

Thanks!

[llvmbot]

Thank you very much, its works for me perfectly. But actually, I have a very different
Problem: As you can see from my bug description i am writing a LLVM SHARC DSP target. The problem is that all SHARC instructions are 48bit long and because i was to lazy to go through TargetInstrDesc::TSFlags i modified tablgen CodeEmitterGen.cpp for me to support 64bit instructions.
So i can write in SharcInstrFormats.td:
class SharcInst<dag outOpList, dag inOpList, string asmStr, list pattern> :
Instruction {

// The namespace.
let Namespace = "sharc";

// Set the input and output operands.
let OutOperandList = outOpList;
let InOperandList = inOpList;

// ....

// <<<<<<<<<< This works perfectly with modified tablegen
field bits<48> Inst;

}
Of course the XXXCodeEmitter::getBinaryCodeForInstr(...) return type changed and all the other targets, which need the previous return type don't compile.

It would be very nice, if tablegen would support 64bit instructions.

Thank you.

Fixed with a slightly different approach, please verify that this works for
you:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20080929/068087.html

Thanks!