Prathamesh Kulkarni <prathamesh.kulka...@linaro.org> writes:
> diff --git a/gcc/fwprop.c b/gcc/fwprop.c
> index 45703fe5f01..93a1a10c9a6 100644
> --- a/gcc/fwprop.c
> +++ b/gcc/fwprop.c
> @@ -547,6 +547,54 @@ propagate_rtx_1 (rtx *px, rtx old_rtx, rtx new_rtx, int
> flags)
> tem = simplify_gen_subreg (mode, op0, GET_MODE (SUBREG_REG (x)),
> SUBREG_BYTE (x));
> }
> +
> + else
> + {
> + rtvec vec;
> + rtvec newvec;
> + const char *fmt = GET_RTX_FORMAT (code);
> + rtx op;
> +
> + for (int i = 0; fmt[i]; i++)
> + switch (fmt[i])
> + {
> + case 'E':
> + vec = XVEC (x, i);
> + newvec = vec;
> + for (int j = 0; j < GET_NUM_ELEM (vec); j++)
> + {
> + op = RTVEC_ELT (vec, j);
> + valid_ops &= propagate_rtx_1 (&op, old_rtx, new_rtx, flags);
> + if (op != RTVEC_ELT (vec, j))
> + {
> + if (newvec == vec)
> + {
> + newvec = shallow_copy_rtvec (vec);
> + if (!tem)
> + tem = shallow_copy_rtx (x);
> + XVEC (tem, i) = newvec;
> + }
> + RTVEC_ELT (newvec, j) = op;
> + }
> + }
> + break;
Misindented break: should be indented two columns further.
> +
> + case 'e':
> + if (XEXP (x, i))
> + {
> + op = XEXP (x, i);
> + valid_ops &= propagate_rtx_1 (&op, old_rtx, new_rtx, flags);
> + if (op != XEXP (x, i))
> + {
> + if (!tem)
> + tem = shallow_copy_rtx (x);
> + XEXP (tem, i) = op;
> + }
> + }
> + break;
Same here.
> + }
> + }
> +
> break;
>
> case RTX_OBJ:
> @@ -1370,10 +1418,11 @@ forward_propagate_and_simplify (df_ref use, rtx_insn
> *def_insn, rtx def_set)
>
> /* Given a use USE of an insn, if it has a single reaching
> definition, try to forward propagate it into that insn.
> - Return true if cfg cleanup will be needed. */
> + Return true if cfg cleanup will be needed.
> + REG_PROP_ONLY is true if we should only propagate register copies. */
>
> static bool
> -forward_propagate_into (df_ref use)
> +forward_propagate_into (df_ref use, bool reg_prop_only = false)
> {
> df_ref def;
> rtx_insn *def_insn, *use_insn;
> @@ -1394,10 +1443,6 @@ forward_propagate_into (df_ref use)
> if (DF_REF_IS_ARTIFICIAL (def))
> return false;
>
> - /* Do not propagate loop invariant definitions inside the loop. */
> - if (DF_REF_BB (def)->loop_father != DF_REF_BB (use)->loop_father)
> - return false;
> -
> /* Check if the use is still present in the insn! */
> use_insn = DF_REF_INSN (use);
> if (DF_REF_FLAGS (use) & DF_REF_IN_NOTE)
> @@ -1415,6 +1460,16 @@ forward_propagate_into (df_ref use)
> if (!def_set)
> return false;
>
> + if (reg_prop_only && !REG_P (SET_SRC (def_set)))
> + return false;
> +
> + /* Allow propagating def inside loop only if source of def_set is
> + reg, since replacing reg by source reg shouldn't increase cost. */
Maybe:
/* Allow propagations into a loop only for reg-to-reg copies, since
replacing one register by another shouldn't increase the cost. */
> +
> + if (DF_REF_BB (def)->loop_father != DF_REF_BB (use)->loop_father
> + && !REG_P (SET_SRC (def_set)))
> + return false;
To be extra safe, I think we should check that the SET_DEST is a REG_P
in both cases, to exclude REG-to-SUBREG copies.
Thanks,
Richard
