On Thu, Aug 15, 2024 at 11:34 AM Roger Sayle <ro...@nextmovesoftware.com> wrote:
>
>
> As requested this patch is split out from my earlier submission.
> This patch provides more accurate costs/gains for (wide) immediate
> constants in STV, suitably adjusting the costs/gains when the highpart
> and lowpart words are the same. One minor complication is that the
> middle-end assumes (when generating memset) that SSE constants will
> be shared/amortized across multiple consecutive writes. Hence to
> avoid testsuite regressions, we add a heuristic that considers an immediate
> constant to be very cheap, if that same immediate value occurs in the
> previous instruction or in the following instruction.
>
> This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> and make -k check, both with and without --target_board=unix{-m32}
> with no new failures. Ok for mainline?
>
>
> 2024-08-15 Roger Sayle <ro...@nextmovesoftware.com>
>
> gcc/ChangeLog
> * config/i386/i386-features.cc (timode_immed_const_gain): New
> function to determine the gain/cost on a CONST_WIDE_INT.
> (local_duplicate_constant_p): Helper function to see if the
> same immediate constant appears in the previous or next insn.
> (timode_scalar_chain::compute_convert_gain): Fix whitespace.
> <case CONST_WIDE_INT>: Provide more accurate estimates using
> timode_immed_const_gain and local_duplicate_constant_p.
> <case AND>: Handle CONSTANT_SCALAR_INT_P (src).
LGTM.
Thanks,
Uros.
