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Re: RFA: RTL typesafety improvements for ira.c
- From: Jeff Law <law at redhat dot com>
- To: David Malcolm <dmalcolm at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 02 Oct 2014 12:03:55 -0600
- Subject: Re: RFA: RTL typesafety improvements for ira.c
- Authentication-results: sourceware.org; auth=none
- References: <542C8168 dot 4030409 at redhat dot com> <1412206034 dot 16438 dot 89 dot camel at surprise>
On 10/01/14 17:27, David Malcolm wrote:
On Wed, 2014-10-01 at 16:34 -0600, Jeff Law wrote:
This was inspired by a discussion with Felix who was making changes in
Basically this promotes the "init_insns" field within struct equivalence
from an rtx to an rtx_insn_list.
The only thing that's really interesting here is the old code exploits
the fact that we could put any RTX in the list by shoving const0_rtx
into the init_insns list as a marker to indicate we've already
determined the relevant pseudo must not have an equivalence.
Thus we could have the following objects in the init_insns field:
This patch uses INSN_LIST (NULL_RTX, NULL) as the special marker. Thus
the only two things that would exist in the init_insns field would be
NULL or an INSN_LIST. Goodness.
Rather than stash away the special marker INSN_LIST into a global
variable or something similar, we instead to do a two step check for the
marker. First verify that the insn_list field is non-NULL, then look at
the first insn in the list and see if that is NULL.
Bootstrapped and regression tested on i686-unknown-linux-gnu and
Ok for the trunk?
* ira.c (struct equivalence): Promote INIT_INSNs field to
an rtx_insn_list. Add comments.
(no_equiv): Promote LIST to an rtx_insn_list. Update
testing for and creating the special marker. Use methods
to extract the insn and next pointers.
(update_equiv_regs): Update test for special marker in the
diff --git a/gcc/ira.c b/gcc/ira.c
@@ -3258,9 +3266,9 @@ no_equiv (rtx reg, const_rtx store ATTRIBUTE_UNUSED,
ira_reg_equiv[regno].defined_p = false;
ira_reg_equiv[regno].init_insns = NULL;
- for (; list; list = XEXP (list, 1))
+ for (; list; list = list->next ())
- rtx insn = XEXP (list, 0);
+ rtx insn = list->insn ();
remove_note (insn, find_reg_note (insn, REG_EQUIV, NULL_RTX));
FWIW, presumably "insn" here also can now be an rtx_insn *?
Yes. I'll update that. Thanks.