mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-04-11 09:40:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

i386: Also adjust stack frame for stack slot alignment

Browse Source 
We should also adjust stack_realign_offset for the largest alignment of
stack slot actually used when stack realignment isn't needed.  This is
required to keep stack frame properly aligned to satisfy the largest
alignment of stack slots.

Tested on Linux/i686 and Linux/x86-64.

gcc/

	PR target/83735
	* config/i386/i386.c (ix86_compute_frame_layout): Always adjust
	stack_realign_offset for the largest alignment of stack slot
	actually used.
	(ix86_find_max_used_stack_alignment): New function.
	(ix86_finalize_stack_frame_flags): Use it.  Set
	max_used_stack_alignment if we don't realign stack.
	* config/i386/i386.h (machine_function): Add
	max_used_stack_alignment.

gcc/testsuite/

	PR target/83735
	* gcc.target/i386/pr83735.c: New test.

From-SVN: r256436
This commit is contained in:
H.J. Lu 2018-01-10 15:37:49 +00:00 committed by H.J. Lu
parent 447fb74d97
commit cd3410cc7b
5 changed files with 148 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
gcc/ChangeLog
View File

@ -1,3 +1,15 @@
2018-01-10 H.J. Lu <hongjiu.lu@intel.com>
PR target/83735
* config/i386/i386.c (ix86_compute_frame_layout): Always adjust
stack_realign_offset for the largest alignment of stack slot
actually used.
(ix86_find_max_used_stack_alignment): New function.
(ix86_finalize_stack_frame_flags): Use it. Set
max_used_stack_alignment if we don't realign stack.
* config/i386/i386.h (machine_function): Add
max_used_stack_alignment.
2018-01-10 Christophe Lyon <christophe.lyon@linaro.org>
* config/arm/arm.opt (-mbranch-cost): New option.

120
gcc/config/i386/i386.c
View File

@ -11259,7 +11259,11 @@ ix86_compute_frame_layout (void)
/* Calculate the size of the va-arg area (not including padding, if any). */
frame->va_arg_size = ix86_varargs_gpr_size + ix86_varargs_fpr_size;
if (stack_realign_fp)
/* Also adjust stack_realign_offset for the largest alignment of
stack slot actually used. */
if (stack_realign_fp
|| (cfun->machine->max_used_stack_alignment != 0
&& (offset % cfun->machine->max_used_stack_alignment) != 0))
{
/* We may need a 16-byte aligned stack for the remainder of the
register save area, but the stack frame for the local function
@ -12668,6 +12672,62 @@ output_probe_stack_range (rtx reg, rtx end)
return "";
}
/* Return true if stack frame is required. Update STACK_ALIGNMENT
to the largest alignment, in bits, of stack slot used if stack
frame is required and CHECK_STACK_SLOT is true. */
static bool
ix86_find_max_used_stack_alignment (unsigned int &stack_alignment,
bool check_stack_slot)
{
HARD_REG_SET set_up_by_prologue, prologue_used;
basic_block bb;
CLEAR_HARD_REG_SET (prologue_used);
CLEAR_HARD_REG_SET (set_up_by_prologue);
add_to_hard_reg_set (&set_up_by_prologue, Pmode, STACK_POINTER_REGNUM);
add_to_hard_reg_set (&set_up_by_prologue, Pmode, ARG_POINTER_REGNUM);
add_to_hard_reg_set (&set_up_by_prologue, Pmode,
HARD_FRAME_POINTER_REGNUM);
/* The preferred stack alignment is the minimum stack alignment. */
if (stack_alignment > crtl->preferred_stack_boundary)
stack_alignment = crtl->preferred_stack_boundary;
bool require_stack_frame = false;
FOR_EACH_BB_FN (bb, cfun)
{
rtx_insn *insn;
FOR_BB_INSNS (bb, insn)
if (NONDEBUG_INSN_P (insn)
&& requires_stack_frame_p (insn, prologue_used,
set_up_by_prologue))
{
require_stack_frame = true;
if (check_stack_slot)
{
/* Find the maximum stack alignment. */
subrtx_iterator::array_type array;
FOR_EACH_SUBRTX (iter, array, PATTERN (insn), ALL)
if (MEM_P (*iter)
&& (reg_mentioned_p (stack_pointer_rtx,
*iter)
|| reg_mentioned_p (frame_pointer_rtx,
*iter)))
{
unsigned int alignment = MEM_ALIGN (*iter);
if (alignment > stack_alignment)
stack_alignment = alignment;
}
}
}
}
return require_stack_frame;
}
/* Finalize stack_realign_needed and frame_pointer_needed flags, which
will guide prologue/epilogue to be generated in correct form. */
@ -12718,52 +12778,8 @@ ix86_finalize_stack_frame_flags (void)
&& ix86_nsaved_sseregs () == 0
&& ix86_varargs_gpr_size + ix86_varargs_fpr_size == 0)
{
HARD_REG_SET set_up_by_prologue, prologue_used;
basic_block bb;
CLEAR_HARD_REG_SET (prologue_used);
CLEAR_HARD_REG_SET (set_up_by_prologue);
add_to_hard_reg_set (&set_up_by_prologue, Pmode, STACK_POINTER_REGNUM);
add_to_hard_reg_set (&set_up_by_prologue, Pmode, ARG_POINTER_REGNUM);
add_to_hard_reg_set (&set_up_by_prologue, Pmode,
HARD_FRAME_POINTER_REGNUM);
/* The preferred stack alignment is the minimum stack alignment. */
if (stack_alignment > crtl->preferred_stack_boundary)
stack_alignment = crtl->preferred_stack_boundary;
bool require_stack_frame = false;
FOR_EACH_BB_FN (bb, cfun)
{
rtx_insn *insn;
FOR_BB_INSNS (bb, insn)
if (NONDEBUG_INSN_P (insn)
&& requires_stack_frame_p (insn, prologue_used,
set_up_by_prologue))
{
require_stack_frame = true;
if (stack_realign)
{
/* Find the maximum stack alignment. */
subrtx_iterator::array_type array;
FOR_EACH_SUBRTX (iter, array, PATTERN (insn), ALL)
if (MEM_P (*iter)
&& (reg_mentioned_p (stack_pointer_rtx,
*iter)
|| reg_mentioned_p (frame_pointer_rtx,
*iter)))
{
unsigned int alignment = MEM_ALIGN (*iter);
if (alignment > stack_alignment)
stack_alignment = alignment;
}
}
}
}
if (require_stack_frame)
if (ix86_find_max_used_stack_alignment (stack_alignment,
stack_realign))
{
/* Stack frame is required. If stack alignment needed is less
than incoming stack boundary, don't realign stack. */
@ -12851,6 +12867,16 @@ ix86_finalize_stack_frame_flags (void)
recompute_frame_layout_p = true;
}
}
else if (crtl->max_used_stack_slot_alignment
> crtl->preferred_stack_boundary)
{
/* We don't need to realign stack. But we still need to keep
stack frame properly aligned to satisfy the largest alignment
of stack slots. */
if (ix86_find_max_used_stack_alignment (stack_alignment, true))
cfun->machine->max_used_stack_alignment
= stack_alignment / BITS_PER_UNIT;
}
if (crtl->stack_realign_needed != stack_realign)
recompute_frame_layout_p = true;

3
gcc/config/i386/i386.h
View File

@ -2598,6 +2598,9 @@ struct GTY(()) machine_function {
/* Nonzero if the function places outgoing arguments on stack. */
BOOL_BITFIELD outgoing_args_on_stack : 1;
/* The largest alignment, in bytes, of stack slot actually used. */
unsigned int max_used_stack_alignment;
/* During prologue/epilogue generation, the current frame state.
Otherwise, the frame state at the end of the prologue. */
struct machine_frame_state fs;

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2018-01-10 H.J. Lu <hongjiu.lu@intel.com>
PR target/83735
* gcc.target/i386/pr83735.c: New test.
2018-01-10 Christophe Lyon <christophe.lyon@linaro.org>
* lib/target-supports.exp (check_effective_target_branch_cost):

55
gcc/testsuite/gcc.target/i386/pr83735.c Normal file
View File

@ -0,0 +1,55 @@
/* { dg-do run } */
/* { dg-require-effective-target avx } */
/* { dg-options "-O3 -mavx" } */
#include <stdlib.h>
#include "cpuid.h"
#include "m256-check.h"
#include "avx-os-support.h"
static void __attribute__((constructor))
check_avx (void)
{
unsigned int eax, ebx, ecx, edx;
if (!__get_cpuid (1, &eax, &ebx, &ecx, &edx))
exit (0);
/* Run AVX test only if host has AVX support. */
if (((ecx & (bit_AVX | bit_OSXSAVE)) == (bit_AVX | bit_OSXSAVE))
&& avx_os_support ())
return;
exit (0);
}
struct S
{
short b;
long c;
char d;
long e;
unsigned:8;
};
int f, h, k, l;
int g[10];
volatile struct S j;
char m;
int
main (void)
{
int i;
struct S n;
for (i = 0; i < 6; i++)
{
for (f = 0; f < 10; f++)
g[f] = 4;
n = j;
h = m == 0 ? 1 : 5 % m;
if (l)
n.b = k;
}
return n.b;
}