From: Lynn Boger <laboger@linux.vnet.ibm.com>
To: David Edelsohn <dje.gcc@gmail.com>, Alan Modra <amodra@gmail.com>
Cc: gcc-patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Fix PR66870 ppc64le, ppc64 split stack
Date: Wed, 05 Aug 2015 01:22:00 -0000 [thread overview]
Message-ID: <55C16565.5020304@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAGWvnykhSUiN4NREQ2_zK4fR8b8D13ozV=SxqYSvG8A5FbQQLw@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 2416 bytes --]
Updated changelog and attached patch based on Alan's comments.
gcc/ChangeLog
2015-07-30 Lynn Boger <laboger@linux.vnet.ibm.com>
PR66870
* gcc/config/rs6000/rs6000.c (rs6000_emit_prologue): Check for
no_split_stack function attribute along with flag_split_stack.
(rs6000_expand_split_stack_prologue): Likewise.
On 7/31/2015 4:00 AM, David Edelsohn wrote:
> On Fri, Jul 31, 2015 at 12:00 AM, Alan Modra <amodra@gmail.com> wrote:
>> On Thu, Jul 30, 2015 at 03:30:12PM -0500, Lynn A. Boger wrote:
>>> PR66870
>>> * gcc/config/rs6000/rs6000.c: Add check for no_split_stack
>>> function attribute along with flag_split_stack check to
>>> determine when to generate split stack prologue for
>>> ppc64 and ppc64le.
>> Looks good to me, except that the changelog entry should mention the
>> modified functions, for example:
>>
>> PR target/66870
>> * gcc/config/rs6000/rs6000.c (rs6000_emit_prologue): Check for
>> no_split_stack function attribute along with flag_split_stack.
>> (rs6000_expand_split_stack_prologue): Likewise.
>>
>> Also, formatting rules for gcc say to not split a line after an
>> operator.
>>
>>> + int using_split_stack = flag_split_stack &&
>>> + (lookup_attribute ("no_split_stack", DECL_ATTRIBUTES (cfun->decl))
>>> + == NULL);
>> The "&&" belongs on the next line, with parentheses added so that emacs
>> and indent will line up the continuation nicely.
>>
>> int using_split_stack = (flag_split_stack
>> && (lookup_attribute ("no_split_stack",
>> DECL_ATTRIBUTES (cfun->decl))
>> == NULL));
>>
>>
>> David, the following is another piece of the PR66870 fixes. This
>> stops shrink-wrap from moving insns around in the first few blocks of
>> a function, in a way that is incorrect given that r12 is live.
>> Bootstrapped and regression tested powerpc64le-linux (and
>> powerpc64-linux by Lynn).
>>
>> PR target/66870
>> * config/rs6000/rs6000.c (machine_function): Add split_stack_argp_used.
>> (rs6000_emit_prologue): Set it.
>> (rs6000_set_up_by_prologue): Specify r12 when split_stack_argp_used.
> Both patches with your suggested changes are okay.
>
> Thanks, David
>
>
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Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 226606)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -23748,6 +23748,11 @@
int using_static_chain_p = (cfun->static_chain_decl != NULL_TREE
&& df_regs_ever_live_p (STATIC_CHAIN_REGNUM)
&& call_used_regs[STATIC_CHAIN_REGNUM]);
+ int using_split_stack = (flag_split_stack
+ && (lookup_attribute ("no_split_stack",
+ DECL_ATTRIBUTES (cfun->decl))
+ == NULL));
+
/* Offset to top of frame for frame_reg and sp respectively. */
HOST_WIDE_INT frame_off = 0;
HOST_WIDE_INT sp_off = 0;
@@ -24018,7 +24023,7 @@
&& info->cr_save_p
&& REGNO (frame_reg_rtx) != cr_save_regno
&& !(using_static_chain_p && cr_save_regno == 11)
- && !(flag_split_stack && cr_save_regno == 12 && sp_adjust))
+ && !(using_split_stack && cr_save_regno == 12 && sp_adjust))
{
cr_save_rtx = gen_rtx_REG (SImode, cr_save_regno);
START_USE (cr_save_regno);
@@ -24596,7 +24601,7 @@
if ((DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_ELFv2)
&& !using_static_chain_p)
save_regno = 11;
- else if (flag_split_stack || REGNO (frame_reg_rtx) == 12)
+ else if (using_split_stack || REGNO (frame_reg_rtx) == 12)
{
save_regno = 11;
if (using_static_chain_p)
@@ -24699,7 +24704,7 @@
emit_insn (gen_frame_store (reg, sp_reg_rtx, RS6000_TOC_SAVE_SLOT));
}
- if (flag_split_stack && split_stack_arg_pointer_used_p ())
+ if (using_split_stack && split_stack_arg_pointer_used_p ())
{
/* Set up the arg pointer (r12) for -fsplit-stack code. If
__morestack was called, it left the arg pointer to the old
@@ -26287,7 +26292,10 @@
static rtx
rs6000_internal_arg_pointer (void)
{
- if (flag_split_stack)
+ if (flag_split_stack
+ && (lookup_attribute ("no_split_stack", DECL_ATTRIBUTES (cfun->decl))
+ == NULL))
+
{
if (cfun->machine->split_stack_arg_pointer == NULL_RTX)
{
prev parent reply other threads:[~2015-08-05 1:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-30 21:10 Lynn A. Boger
2015-07-31 8:11 ` Alan Modra
2015-07-31 9:31 ` David Edelsohn
2015-08-05 1:22 ` Lynn Boger [this message]
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