On Fri, 2020-04-10 at 18:00 -0500, acsawdey via Gcc-patches wrote:
> One of the things that address_to_insn_form() is used for is
> determining
> whether a PC-relative addressing instruction could be used. In
> particular predicate pcrel_external_address and function
> prefixed_paddi_p() both use it for this purpose. So what emerged in
> PR/94542 is that it should be looking to see if the associated
> symbol_ref is a TLS symbol of some kind. TLS symbols cannot be
> addressed
> with PC-relative. This patch fixes both places in
> address_to_insn_form()
> where it is looking at a symbol_ref.
>
> Regression tests passed with trunk
> 38e62001c576b8c6ba2e08eb4673d69ec4c5b0f9 on ppc64le power9, and
> PC-relative code is now correct. OK for trunk?
>
> Thanks!
> Aaron
>
> 2020-04-10 Aaron Sawdey <acsaw...@linux.ibm.com>
>
> PR target/94542
> * config/rs6000/rs6000.c (address_to_insn_form): Do not attempt
> to
> use PC-relative addressing for TLS references.
> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> index 2b6613bcb7e..c77e60a718f 100644
> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c
> @@ -24824,15 +24824,21 @@ address_to_insn_form (rtx addr,
> if (GET_RTX_CLASS (GET_CODE (addr)) == RTX_AUTOINC)
> return INSN_FORM_UPDATE;
>
> - /* Handle PC-relative symbols and labels. Check for both local and
> external
> - symbols. Assume labels are always local. */
> + /* Handle PC-relative symbols and labels. Check for both local and
> + external symbols. Assume labels are always local. TLS symbols
> + are not PC-relative. */
Does the assumption need a qualifier for target rs6000? (or some combination
of TLS/PC-relative?) There are users of the LABEL_REF_NONLOCAL_P() for
mips,pa,sparc targets.
> if (TARGET_PCREL)
> {
> - if (SYMBOL_REF_P (addr) && !SYMBOL_REF_LOCAL_P (addr))
> - return INSN_FORM_PCREL_EXTERNAL;
> -
> - if (SYMBOL_REF_P (addr) || LABEL_REF_P (addr))
> + if (LABEL_REF_P (addr))
> return INSN_FORM_PCREL_LOCAL;
lgtm.
> +
> + if (SYMBOL_REF_P (addr) && !SYMBOL_REF_TLS_MODEL (addr))
> + {
> + if (!SYMBOL_REF_LOCAL_P (addr))
> + return INSN_FORM_PCREL_EXTERNAL;
> + else
> + return INSN_FORM_PCREL_LOCAL;
> + }
> }
lgtm.
>
> if (GET_CODE (addr) == CONST)
> @@ -24866,14 +24872,19 @@ address_to_insn_form (rtx addr,
> return INSN_FORM_BAD;
>
> /* Check for local and external PC-relative addresses. Labels are always
> - local. */
> + local. TLS symbols are not PC-relative. */
> if (TARGET_PCREL)
> {
> - if (SYMBOL_REF_P (op0) && !SYMBOL_REF_LOCAL_P (op0))
> - return INSN_FORM_PCREL_EXTERNAL;
> -
> - if (SYMBOL_REF_P (op0) || LABEL_REF_P (op0))
> + if (LABEL_REF_P (op0))
> return INSN_FORM_PCREL_LOCAL;
> +
> + if (SYMBOL_REF_P (op0) && !SYMBOL_REF_TLS_MODEL (op0))
> + {
> + if (!SYMBOL_REF_LOCAL_P (op0))
> + return INSN_FORM_PCREL_EXTERNAL;
> + else
> + return INSN_FORM_PCREL_LOCAL;
> + }
lgtm
Thanks
-Will
> }
>
> /* If it isn't PC-relative, the address must use a base register. */
>
