On Thu, 11 Apr 2019, Jakub Jelinek wrote:
> On Thu, Apr 11, 2019 at 09:54:24AM +0200, Richard Biener wrote:
> > > The following patch just punts if we find loads from stack slots in
> > > between
> > > where they are pushed and the const/pure call. In addition to that, I've
> > > outlined the same largish sequence that had 3 copies in the function
> > > already
> > > and I'd need to add 4th copy, so in the end the dce.c changes are removing
> > > more than adding:
> > > 1 file changed, 118 insertions(+), 135 deletions(-)
> >
> > The refactoring itself is probably OK (and if done separately
> > makes reviewing easier).
>
> Here is just the refactoring, ok for trunk?
OK.
Thanks,
Richard.
> 2019-04-11 Jakub Jelinek <ja...@redhat.com>
>
> PR rtl-optimization/89965
> * dce.c (sp_based_mem_offset): New function.
> (find_call_stack_args): Use sp_based_mem_offset.
>
> --- gcc/dce.c.jj 2019-04-11 10:26:18.509365653 +0200
> +++ gcc/dce.c 2019-04-11 10:30:00.436705065 +0200
> @@ -272,6 +272,58 @@ check_argument_store (HOST_WIDE_INT size
> return true;
> }
>
> +/* If MEM has sp address, return 0, if it has sp + const address,
> + return that const, if it has reg address where reg is set to sp + const
> + and FAST is false, return const, otherwise return
> + INTTYPE_MINUMUM (HOST_WIDE_INT). */
> +
> +static HOST_WIDE_INT
> +sp_based_mem_offset (rtx_call_insn *call_insn, const_rtx mem, bool fast)
> +{
> + HOST_WIDE_INT off = 0;
> + rtx addr = XEXP (mem, 0);
> + if (GET_CODE (addr) == PLUS
> + && REG_P (XEXP (addr, 0))
> + && CONST_INT_P (XEXP (addr, 1)))
> + {
> + off = INTVAL (XEXP (addr, 1));
> + addr = XEXP (addr, 0);
> + }
> + if (addr == stack_pointer_rtx)
> + return off;
> +
> + if (!REG_P (addr) || fast)
> + return INTTYPE_MINIMUM (HOST_WIDE_INT);
> +
> + /* If not fast, use chains to see if addr wasn't set to sp + offset. */
> + df_ref use;
> + FOR_EACH_INSN_USE (use, call_insn)
> + if (rtx_equal_p (addr, DF_REF_REG (use)))
> + break;
> +
> + if (use == NULL)
> + return INTTYPE_MINIMUM (HOST_WIDE_INT);
> +
> + struct df_link *defs;
> + for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
> + if (! DF_REF_IS_ARTIFICIAL (defs->ref))
> + break;
> +
> + if (defs == NULL)
> + return INTTYPE_MINIMUM (HOST_WIDE_INT);
> +
> + rtx set = single_set (DF_REF_INSN (defs->ref));
> + if (!set)
> + return INTTYPE_MINIMUM (HOST_WIDE_INT);
> +
> + if (GET_CODE (SET_SRC (set)) != PLUS
> + || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
> + || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
> + return INTTYPE_MINIMUM (HOST_WIDE_INT);
> +
> + off += INTVAL (XEXP (SET_SRC (set), 1));
> + return off;
> +}
>
> /* Try to find all stack stores of CALL_INSN arguments if
> ACCUMULATE_OUTGOING_ARGS. If all stack stores have been found
> @@ -309,58 +361,13 @@ find_call_stack_args (rtx_call_insn *cal
> if (GET_CODE (XEXP (p, 0)) == USE
> && MEM_P (XEXP (XEXP (p, 0), 0)))
> {
> - rtx mem = XEXP (XEXP (p, 0), 0), addr;
> - HOST_WIDE_INT off = 0, size;
> + rtx mem = XEXP (XEXP (p, 0), 0);
> + HOST_WIDE_INT size;
> if (!MEM_SIZE_KNOWN_P (mem) || !MEM_SIZE (mem).is_constant (&size))
> return false;
> - addr = XEXP (mem, 0);
> - if (GET_CODE (addr) == PLUS
> - && REG_P (XEXP (addr, 0))
> - && CONST_INT_P (XEXP (addr, 1)))
> - {
> - off = INTVAL (XEXP (addr, 1));
> - addr = XEXP (addr, 0);
> - }
> - if (addr != stack_pointer_rtx)
> - {
> - if (!REG_P (addr))
> - return false;
> - /* If not fast, use chains to see if addr wasn't set to
> - sp + offset. */
> - if (!fast)
> - {
> - df_ref use;
> - struct df_link *defs;
> - rtx set;
> -
> - FOR_EACH_INSN_USE (use, call_insn)
> - if (rtx_equal_p (addr, DF_REF_REG (use)))
> - break;
> -
> - if (use == NULL)
> - return false;
> -
> - for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
> - if (! DF_REF_IS_ARTIFICIAL (defs->ref))
> - break;
> -
> - if (defs == NULL)
> - return false;
> -
> - set = single_set (DF_REF_INSN (defs->ref));
> - if (!set)
> - return false;
> -
> - if (GET_CODE (SET_SRC (set)) != PLUS
> - || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
> - || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
> - return false;
> -
> - off += INTVAL (XEXP (SET_SRC (set), 1));
> - }
> - else
> - return false;
> - }
> + HOST_WIDE_INT off = sp_based_mem_offset (call_insn, mem, fast);
> + if (off == INTTYPE_MINIMUM (HOST_WIDE_INT))
> + return false;
> min_sp_off = MIN (min_sp_off, off);
> max_sp_off = MAX (max_sp_off, off + size);
> }
> @@ -376,51 +383,19 @@ find_call_stack_args (rtx_call_insn *cal
> if (GET_CODE (XEXP (p, 0)) == USE
> && MEM_P (XEXP (XEXP (p, 0), 0)))
> {
> - rtx mem = XEXP (XEXP (p, 0), 0), addr;
> - HOST_WIDE_INT off = 0, byte, size;
> + rtx mem = XEXP (XEXP (p, 0), 0);
> /* Checked in the previous iteration. */
> - size = MEM_SIZE (mem).to_constant ();
> - addr = XEXP (mem, 0);
> - if (GET_CODE (addr) == PLUS
> - && REG_P (XEXP (addr, 0))
> - && CONST_INT_P (XEXP (addr, 1)))
> - {
> - off = INTVAL (XEXP (addr, 1));
> - addr = XEXP (addr, 0);
> - }
> - if (addr != stack_pointer_rtx)
> - {
> - df_ref use;
> - struct df_link *defs;
> - rtx set;
> -
> - FOR_EACH_INSN_USE (use, call_insn)
> - if (rtx_equal_p (addr, DF_REF_REG (use)))
> - break;
> -
> - for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
> - if (! DF_REF_IS_ARTIFICIAL (defs->ref))
> - break;
> -
> - set = single_set (DF_REF_INSN (defs->ref));
> - off += INTVAL (XEXP (SET_SRC (set), 1));
> - }
> - for (byte = off; byte < off + size; byte++)
> - {
> - if (!bitmap_set_bit (sp_bytes, byte - min_sp_off))
> - gcc_unreachable ();
> - }
> + HOST_WIDE_INT size = MEM_SIZE (mem).to_constant ();
> + HOST_WIDE_INT off = sp_based_mem_offset (call_insn, mem, fast);
> + gcc_checking_assert (off != INTTYPE_MINIMUM (HOST_WIDE_INT));
> + for (HOST_WIDE_INT byte = off; byte < off + size; byte++)
> + if (!bitmap_set_bit (sp_bytes, byte - min_sp_off))
> + gcc_unreachable ();
> }
>
> - /* Walk backwards, looking for argument stores. The search stops
> - when seeing another call, sp adjustment or memory store other than
> - argument store. */
> ret = false;
> for (insn = PREV_INSN (call_insn); insn; insn = prev_insn)
> {
> - rtx set, mem, addr;
> - HOST_WIDE_INT off;
> -
> if (insn == BB_HEAD (BLOCK_FOR_INSN (call_insn)))
> prev_insn = NULL;
> else
> @@ -432,61 +407,17 @@ find_call_stack_args (rtx_call_insn *cal
> if (!NONDEBUG_INSN_P (insn))
> continue;
>
> - set = single_set (insn);
> + rtx set = single_set (insn);
> if (!set || SET_DEST (set) == stack_pointer_rtx)
> break;
>
> if (!MEM_P (SET_DEST (set)))
> continue;
>
> - mem = SET_DEST (set);
> - addr = XEXP (mem, 0);
> - off = 0;
> - if (GET_CODE (addr) == PLUS
> - && REG_P (XEXP (addr, 0))
> - && CONST_INT_P (XEXP (addr, 1)))
> - {
> - off = INTVAL (XEXP (addr, 1));
> - addr = XEXP (addr, 0);
> - }
> - if (addr != stack_pointer_rtx)
> - {
> - if (!REG_P (addr))
> - break;
> - if (!fast)
> - {
> - df_ref use;
> - struct df_link *defs;
> - rtx set;
> -
> - FOR_EACH_INSN_USE (use, insn)
> - if (rtx_equal_p (addr, DF_REF_REG (use)))
> - break;
> -
> - if (use == NULL)
> - break;
> -
> - for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
> - if (! DF_REF_IS_ARTIFICIAL (defs->ref))
> - break;
> -
> - if (defs == NULL)
> - break;
> -
> - set = single_set (DF_REF_INSN (defs->ref));
> - if (!set)
> - break;
> -
> - if (GET_CODE (SET_SRC (set)) != PLUS
> - || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
> - || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
> - break;
> -
> - off += INTVAL (XEXP (SET_SRC (set), 1));
> - }
> - else
> - break;
> - }
> + rtx mem = SET_DEST (set);
> + HOST_WIDE_INT off = sp_based_mem_offset (call_insn, mem, fast);
> + if (off == INTTYPE_MINIMUM (HOST_WIDE_INT))
> + break;
>
> HOST_WIDE_INT size;
> if (!MEM_SIZE_KNOWN_P (mem)
>
>
> Jakub
>
--
Richard Biener <rguent...@suse.de>
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany;
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah; HRB 21284 (AG Nürnberg)
