[PATCH] D92156: [PowerPC] Add support for "tlbiel" with two arguments

[Jinsong Ji via Phabricator via llvm-commits]

jsji added a comment.



> Perhaps GNU assembler has a pseudo-instruction for this? If it's not used significantly throughout the Linux kernel, maybe we should change the kernel to use the canonical form of the instruction?

I did some research and chatted with GNU assembler developers. I think the situation is:
Old ISA used to define 2 operands tlbiel, but we changed the format in ISA 3.0 (Power 9) and later , introducing the 5 operands basic form and its one operand extended mnemonic.

So gas supports the 5 operands basic forms only with -mpower9 and up. The 2 operands mnemonic in gas is actually an extended mnemonic with other 3 operands default to 0.

We are working with ISA guys to confirm whether we can support the 2 operands extended mnemonic.

So my recommendation is we should implement according to ISA 3.1 first for now, we can add the two operands InstAlias later if confirmed by ISA .

Regarding to usage in kernel, I think it depends on which arch are you building for, if it's with -mcpu=pwr9 and above, yes, I would recommend we update the code to use 5 operands basic form.


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