Instruction selection - .td file sytax

Beginners
1

Hi,

I’m trying to to something like:
def :PatDSP<(i32 (add ( add (i32 rXRegs:$src2), (shl (i32 rXRegs:$src0), (u3Imm:$src1))),
(shl (i32 rXRegs:$src0), (u3Imm:$src1)))),
(dsp_shiftladd rXRegs:$src0, u3Imm:($src1+1),
rXRegs:$src2)>;

is there a way/syntax to do calculations on the input? I’d like to catch in generic way all imm patterns.

Thanks,
David

2

Hi David,

you can’t do calculations directly in the tablegen language. However, you can introduce new SD nodes to make some calculations. See e.g. the definition of Log2_32 and it’s use in the HexagonPatterns.td file.

Regards,
Kai

3

thanks! that helped