On 5/18/25 2:24 PM, Richard Sandiford wrote:
gcc/
* genemit.cc (gen_rtx_scratch, gen_exp): Use operands[%d] rather than
operand%d.
(start_gen_insn): Store the incoming arguments to an operands array.
(gen_expand, gen_split): Remove copies into and out of the operands
array.
* config/stormy16/stormy16.md (negsi): Remove redundant assignment.
So two questions. Is there any meanginful performance impact expected
here using the array form rather than locals? And does this impact how
folks write their C/C++ fragments in the expanders and such?
I don't think there should be any compile-time impact, and I can't
measure one when compiling fold-const.ii -O0 (my go-to test for this).
Sounds good.
The md interface remains the same, in that all interaction is via the
the operands[] array. Any writes to the individual operandN variables
(where present) are ignored both before and after the patch.
I must have mis-read a bit then. My mental model was we were losing the
operandN interface.
However, I suppose this does make it possible to turn the operandN
arguments into constants, to prevent accidents. I'll try that.
If it works, it's a good idea as I've had to chase down bugs in this
space a few times through the years...
jeff
