On Fri, 7 Jun 2019, Richard Sandiford wrote:
> "H.J. Lu" <hjl.to...@gmail.com> writes:
> > locate_and_pad_parm is called when expanding function call from
> > initialize_argument_information and when generating function body
> > from assign_parm_find_entry_rtl:
> >
> > /* Remember if the outgoing parameter requires extra alignment on the
> > calling function side. */
> > if (crtl->stack_alignment_needed < boundary)
> > crtl->stack_alignment_needed = boundary;
> > if (crtl->preferred_stack_boundary < boundary)
> > crtl->preferred_stack_boundary = boundary;
> >
> > stack_alignment_needed and preferred_stack_boundary should be updated
> > only when expanding function call, not when generating function body.
> > Add an argument, outgoing_p, to locate_and_pad_parm to indicate for
> > expanding function call. Update stack_alignment_needed and
> > preferred_stack_boundary if the parameter is passed on stack and only
> > when expanding function call.
> >
> > Tested on Linux/x86-64.
> >
> > OK for trunk?
> >
> > Thanks.
> >
> > --
> > H.J.
> >
> > From e91e20ad8e10373db2c6d8f99a3da0bbf46c5c34 Mon Sep 17 00:00:00 2001
> > From: "H.J. Lu" <hjl.to...@gmail.com>
> > Date: Wed, 5 Jun 2019 12:55:19 -0700
> > Subject: [PATCH] Update preferred_stack_boundary only when expanding
> > function
> > call
> >
> > locate_and_pad_parm is called when expanding function call from
> > initialize_argument_information and when generating function body
> > from assign_parm_find_entry_rtl:
> >
> > /* Remember if the outgoing parameter requires extra alignment on the
> > calling function side. */
> > if (crtl->stack_alignment_needed < boundary)
> > crtl->stack_alignment_needed = boundary;
> > if (crtl->preferred_stack_boundary < boundary)
> > crtl->preferred_stack_boundary = boundary;
> >
> > stack_alignment_needed and preferred_stack_boundary should be updated
> > only when expanding function call, not when generating function body.
> > Add an argument, outgoing_p, to locate_and_pad_parm to indicate for
> > expanding function call. Update stack_alignment_needed and
> > preferred_stack_boundary if the parameter is passed on stack and only
> > when expanding function call.
> >
> > Tested on Linux/x86-64.
> >
> > gcc/
> >
> > PR rtl-optimization/90765
> > * function.c (assign_parm_find_entry_rtl): Pass false to
> > locate_and_pad_parm.
> > (locate_and_pad_parm): Add an argument, outgoing_p, to indicate
> > for expanding function call. Update stack_alignment_needed and
> > preferred_stack_boundary only if outgoing_p is true and the
> > the parameter is passed on stack.
> > * function.h (locate_and_pad_parm): Add an argument, outgoing_p,
> > defaulting to true.
> >
> > gcc/testsuite/
> >
> > PR rtl-optimization/90765
> > * gcc.target/i386/pr90765-1.c: New test.
> > * gcc.target/i386/pr90765-2.c: Likewise.
> > ---
> > gcc/function.c | 21 +++++++++++++--------
> > gcc/function.h | 3 ++-
> > gcc/testsuite/gcc.target/i386/pr90765-1.c | 11 +++++++++++
> > gcc/testsuite/gcc.target/i386/pr90765-2.c | 18 ++++++++++++++++++
> > 4 files changed, 44 insertions(+), 9 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.target/i386/pr90765-1.c
> > create mode 100644 gcc/testsuite/gcc.target/i386/pr90765-2.c
> >
> > diff --git a/gcc/function.c b/gcc/function.c
> > index e30ee259bec..9b6673f6f0d 100644
> > --- a/gcc/function.c
> > +++ b/gcc/function.c
> > @@ -2601,7 +2601,7 @@ assign_parm_find_entry_rtl (struct
> > assign_parm_data_all *all,
> > locate_and_pad_parm (data->promoted_mode, data->passed_type, in_regs,
> > all->reg_parm_stack_space,
> > entry_parm ? data->partial : 0, current_function_decl,
> > - &all->stack_args_size, &data->locate);
> > + &all->stack_args_size, &data->locate, false);
> >
> > /* Update parm_stack_boundary if this parameter is passed in the
> > stack. */
> > @@ -3954,7 +3954,8 @@ locate_and_pad_parm (machine_mode passed_mode, tree
> > type, int in_regs,
> > int reg_parm_stack_space, int partial,
> > tree fndecl ATTRIBUTE_UNUSED,
> > struct args_size *initial_offset_ptr,
> > - struct locate_and_pad_arg_data *locate)
> > + struct locate_and_pad_arg_data *locate,
> > + bool outgoing_p)
> > {
> > tree sizetree;
> > pad_direction where_pad;
> > @@ -4021,12 +4022,16 @@ locate_and_pad_parm (machine_mode passed_mode, tree
> > type, int in_regs,
> > }
> > }
> >
> > - /* Remember if the outgoing parameter requires extra alignment on the
> > - calling function side. */
> > - if (crtl->stack_alignment_needed < boundary)
> > - crtl->stack_alignment_needed = boundary;
> > - if (crtl->preferred_stack_boundary < boundary)
> > - crtl->preferred_stack_boundary = boundary;
> > + if (outgoing_p && !in_regs)
> > + {
> > + /* Remember if the outgoing parameter requires extra alignment on
> > + the calling function side if this parameter is passed in the
> > + stack. */
> > + if (crtl->stack_alignment_needed < boundary)
> > + crtl->stack_alignment_needed = boundary;
> > + if (crtl->preferred_stack_boundary < boundary)
> > + crtl->preferred_stack_boundary = boundary;
> > + }
>
> Just my opinion, but I think this shows that the code isn't really
> in the right place. IMO locate_and_pad_parm should just describe
> the ABI and is too low-level to be modifying global state like this.
>
> I think we could instead do this by walking over the argument vectors
> in a subroutine of expand_call and emit_library_call_value_1.
> expand_call is also where we do:
>
> /* Ensure current function's preferred stack boundary is at least
> what we need. Stack alignment may also increase preferred stack
> boundary. */
> if (crtl->preferred_stack_boundary < preferred_stack_boundary)
> crtl->preferred_stack_boundary = preferred_stack_boundary;
> else
> preferred_stack_boundary = crtl->preferred_stack_boundary;
Agreed - that would be much cleaner.
Richard.
> Thanks,
> Richard
>
> >
> > if (ARGS_GROW_DOWNWARD)
> > {
> > diff --git a/gcc/function.h b/gcc/function.h
> > index bfe9919a760..5ad7a33fd39 100644
> > --- a/gcc/function.h
> > +++ b/gcc/function.h
> > @@ -613,7 +613,8 @@ extern bool use_register_for_decl (const_tree);
> > extern gimple_seq gimplify_parameters (gimple_seq *);
> > extern void locate_and_pad_parm (machine_mode, tree, int, int, int,
> > tree, struct args_size *,
> > - struct locate_and_pad_arg_data *);
> > + struct locate_and_pad_arg_data *,
> > + bool = true);
> > extern void generate_setjmp_warnings (void);
> >
> > /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
> > diff --git a/gcc/testsuite/gcc.target/i386/pr90765-1.c
> > b/gcc/testsuite/gcc.target/i386/pr90765-1.c
> > new file mode 100644
> > index 00000000000..178c3ff8054
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr90765-1.c
> > @@ -0,0 +1,11 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mavx512f" } */
> > +/* { dg-final { scan-assembler-not "and\[lq\]?\[\\t \]*\\$-64,\[\\t
> > \]*%\[re\]?sp" } } */
> > +
> > +typedef int __v16si __attribute__ ((__vector_size__ (64)));
> > +
> > +void
> > +foo (__v16si x, int i0, int i1, int i2, int i3, int i4, int i5, __v16si *p)
> > +{
> > + *p = x;
> > +}
> > diff --git a/gcc/testsuite/gcc.target/i386/pr90765-2.c
> > b/gcc/testsuite/gcc.target/i386/pr90765-2.c
> > new file mode 100644
> > index 00000000000..45cf1f03747
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/i386/pr90765-2.c
> > @@ -0,0 +1,18 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -mavx512f" } */
> > +/* { dg-final { scan-assembler "and\[lq\]?\[\\t \]*\\$-64,\[\\t
> > \]*%\[re\]?sp" } } */
> > +/* { dg-skip-if "" { x86_64-*-mingw* } } */
> > +
> > +typedef int __v16si __attribute__ ((__vector_size__ (64)));
> > +
> > +extern void foo (__v16si, __v16si, __v16si, __v16si, __v16si, __v16si,
> > + __v16si, __v16si, __v16si, int, int, int, int, int,
> > + int, __v16si *);
> > +
> > +extern __v16si x, y;
> > +
> > +void
> > +bar (void)
> > +{
> > + foo (x, x, x, x, x, x, x, x, x, 0, 1, 2, 3, 4, 5, &y);
> > +}
>
--
Richard Biener <rguent...@suse.de>
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany;
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah; HRB 21284 (AG Nürnberg)
