On Mon, Sep 19, 2011 at 9:08 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> AVX2 prefers v*i128 instructions for vector integer
> modes, while AVX only supports v*f128.
> In one of my recent patches I've changed vextract* so that
> it emits v*i128 instead of v*f128 for AVX2 on integer modes,
> but I wonder what is the prefered way to change the rest
> of the insn.
>
> E.g. we have:
> (define_insn "avx_vbroadcastf128_<mode>"
> [(set (match_operand:V_256 0 "register_operand" "=x,x,x")
> (vec_concat:V_256
> (match_operand:<ssehalfvecmode> 1 "nonimmediate_operand" "m,0,?x")
> (match_dup 1)))]
> "TARGET_AVX"
> "@
> vbroadcastf128\t{%1, %0|%0, %1}
> vinsertf128\t{$1, %1, %0, %0|%0, %0, %1, 1}
> vperm2f128\t{$0, %t1, %t1, %0|%0, %t1, %t1, 0}"
> [(set_attr "type" "ssemov,sselog1,sselog1")
> (set_attr "prefix_extra" "1")
> (set_attr "length_immediate" "0,1,1")
> (set_attr "prefix" "vex")
> (set_attr "mode" "V4SF,V8SF,V8SF")])
>
> One option is change the mode iterator, so that it
> iterates on all 256-bit vectors for !TARGET_AVX2, and only
> for V8SF and V4DF for TARGET_AVX2, then for each such an insn also
> add similar insn that iterates on the 256-bit integer vectors,
> is guarded by TARGET_AVX2 and uses *i128 and OI mode attribute instead of
> V8SF or V4DF.
>
> Or, e.g. we could have operand modifier that would print "i128"
> resp. "i" for TARGET_AVX2 and integer vector modes, and would print
> "f128" resp. "f" otherwise. Still, something would need to be done
> about the mode attribute.
>
> Or something else?
Perhaps use mode attribute that defines "f" for FP modes and "%i" for
integer modes. "%i" is further processed in ix86_output_operand (or
perhaps ASM_OUTPUT_OPCODE, similar to %v ?) to output "i" for
TARGET_AVX2 or "f" otherwise.
Uros.
