On Mon, 23 Apr 2018, Alexander Monakov wrote:
> As discussed in the cover letter, the code removed in this patch is
> unnecessary,
> references to global reg vars from inline asms do not work reliably, and so we
> should simply require that inline asms use constraints to make such references
> properly visible to the compiler.
>
> Bootstrapped/regtested on powerpc64, will retest on ppc64le and x86 in stage
> 1.
>
> PR rtl-optimization/79985
> * df-scan.c (df_insn_refs_collect): Remove special case for
> global registers and asm statements.
Ping. I've retested once on ppc64le since posting.
> ---
> gcc/df-scan.c | 11 -----------
> 1 file changed, 11 deletions(-)
>
> diff --git a/gcc/df-scan.c b/gcc/df-scan.c
> index 95e1e0df2d5..cbb08fc36ae 100644
> --- a/gcc/df-scan.c
> +++ b/gcc/df-scan.c
> @@ -3207,17 +3207,6 @@ df_insn_refs_collect (struct df_collection_rec
> *collection_rec,
> if (CALL_P (insn_info->insn))
> df_get_call_refs (collection_rec, bb, insn_info, flags);
>
> - if (asm_noperands (PATTERN (insn_info->insn)) >= 0)
> - for (unsigned i = 0; i < FIRST_PSEUDO_REGISTER; i++)
> - if (global_regs[i])
> - {
> - /* As with calls, asm statements reference all global regs. */
> - df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
> - NULL, bb, insn_info, DF_REF_REG_USE, flags);
> - df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
> - NULL, bb, insn_info, DF_REF_REG_DEF, flags);
> - }
> -
> /* Record other defs. These should be mostly for DF_REF_REGULAR, so
> that a qsort on the defs is unnecessary in most cases. */
> df_defs_record (collection_rec,
>
