On Mon, Mar 11, 2013 at 12:17 AM, Steven Bosscher <stevenb....@gmail.com> wrote:
> Hello,
>
> RTL PRE has an option to disable load motion. This option works fine,
> except that all analysis for load motion is still performed.
>
> This patch stops gcse.c from recording memory sets for -fno-gcse-lm,
> and conservatively returns true in oprs_unchanged_p for any MEM.
>
> Bootstrapped&tested on {x86_64,powerpc64}-unknown-linux-gnu. OK?
Ok.
Thanks,
Richard.
> Ciao!
> Steven
>
>
> * gcse.c (oprs_unchanged_p): Respect flag_gcse_lm.
> (record_last_mem_set_info): Likewise.
>
> Index: gcse.c
> ===================================================================
> --- gcse.c (revision 196576)
> +++ gcse.c (working copy)
> @@ -890,8 +890,9 @@ oprs_unchanged_p (const_rtx x, const_rtx
> }
>
> case MEM:
> - if (load_killed_in_block_p (current_bb, DF_INSN_LUID (insn),
> - x, avail_p))
> + if (! flag_gcse_lm
> + || load_killed_in_block_p (current_bb, DF_INSN_LUID (insn),
> + x, avail_p))
> return 0;
> else
> return oprs_unchanged_p (XEXP (x, 0), insn, avail_p);
> @@ -1471,10 +1472,14 @@ canon_list_insert (rtx dest ATTRIBUTE_UN
> static void
> record_last_mem_set_info (rtx insn)
> {
> - int bb = BLOCK_FOR_INSN (insn)->index;
> + int bb;
> +
> + if (! flag_gcse_lm)
> + return;
>
> /* load_killed_in_block_p will handle the case of calls clobbering
> everything. */
> + bb = BLOCK_FOR_INSN (insn)->index;
> modify_mem_list[bb].safe_push (insn);
> bitmap_set_bit (modify_mem_list_set, bb);
