Re: [RFA] [V3] new pass for sign/zero extension elimination

[Xi Ruoyao <xry111@xry111.site>]

I have successfully bootstrapped and regtested the patch on loongarch64-
linux-gnu.  The test cases in the patch (intended for RISC-V) also works
on LoongArch per my manual testing.

On Mon, 2024-01-01 at 14:04 -0700, Jeff Law wrote:
> I know we're deep into stage3 and about to transition to stage4.  So if 
> the consensus is for this to wait, I'll understand....
> 
> This it the V3 of the ext-dce patch based on Joern's work from last year.
> 
> Changes since V2:
>    Handle MINUS
>    Minor logic cleanup for SUBREGs in ext_dce_process_sets
>    Includes Joern's carry_backpropagate work
>    Cleaned up and removed some use handling code for STRICT_LOW_PART
>    Moved non-local goto special case out of main use handling, similar to
>    how we handle CALL_INSN_FUSAGE
>    Use df_simple_dataflow rather than custom dataflow handling
> 
> There's more cleanups we could be doing here, but the question is do we 
> stop commit what we've got and iterate on the trunk or do we defer until 
> gcc-15 in which case we iterate on a branch or something.
> 
> This still is enabled at -O1 or above, but that's to get as much testing 
> as possible.  Assuming the rest is ACK'd for the trunk we'll put it into 
> the list of optimizations enabled by -O2.

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University