Re: [xstormy16] Add extendhisi2 and zero_extendhisi2 patterns to stormy16.md

[Jeff Law <jeffreyalaw@gmail.com>]

On 4/22/23 14:57, Roger Sayle wrote:
> 
> This patch adds a pair of define_insn patterns to the xstormy16 machine
> description that provide extendhisi2 and zero_extendhisi2, i.e. 16-bit
> to 32-bit sign- and zero-extension respectively.  This functionality is
> already synthesized during RTL expansion, but providing patterns allow
> the semantics to be exposed to the RTL optimizers.  To simplify things,
> this patch introduces a new %h0 output format, for emitting the high_part
> register name of a double-word (SImode) register pair.  The actual
> code generated is identical to before.
> 
> Whilst there, I also fixed the instruction lengths and formatting of
> the zero_extendqihi2 pattern.  Then, mostly for documentation purposes
> as the 'T' constraint isn't yet implemented, I've added a "and Rx,#255"
> alternative to zero_extendqihi2 that takes advantage of its efficient
> instruction encoding.
> 
> This patch has been tested by building a cross-compiler to xstormy16-elf
> on x86_64-pc-linux-gnu, and confirming that the new test case passes with
> "make -k check-gcc".  Ok for mainline?
> 
> 
> 2023-04-22  Roger Sayle  <roger@nextmovesoftware.com>
> 
> gcc/ChangeLog
>          * config/stormy16/stormy16.cc (xstormy16_print_operand): Add %h
>          format specifier to output high_part register name of SImode reg.
>          * config/stormy16/stormy16.md (extendhisi2): New define_insn.
>          (zero_extendqihi2): Fix lengths, consistent formatting and add
>          "and Rx,#255" alternative, for documentation purposes.
>          (zero_extendhisi2): New define_insn.
> 
> gcc/testsuite/ChangeLog
>          * gcc.target/xstormy16/extendhisi2.c: New test case.
>          * gcc.target/xstormy16/zextendhisi2.c: Likewise.
Does the "T" alternative ever match?  AFAICT its constraint check always 
fails:

> (define_constraint "T"
>   "@internal"
>   ;; For Rx; not implemented yet.
>   (match_test "0"))

No objections, but just not sure what's going on with that T constraint.

jeff