Updated changelog and attached patch based on Alan's comments.
gcc/ChangeLog
2015-07-30 Lynn Boger <labo...@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 <amo...@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
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)
{
