Re: [PATCH] x86-64: Generate push2/pop2 only if the incoming stack is 16-byte aligned
On Wed, Feb 14, 2024 at 5:33 AM H.J. Lu wrote:
>
> Since push2/pop2 requires 16-byte stack alignment, don't generate them
> if the incoming stack isn't 16-byte aligned.
Ok.
>
> gcc/
>
> PR target/113912
> * config/i386/i386.cc (ix86_can_use_push2pop2): New.
> (ix86_pro_and_epilogue_can_use_push2pop2): Use it.
> (ix86_emit_save_regs): Don't generate push2 if
> ix86_can_use_push2pop2 return false.
> (ix86_expand_epilogue): Don't generate pop2 if
> ix86_can_use_push2pop2 return false.
>
> gcc/testsuite/
>
> PR target/113912
> * gcc.target/i386/apx-push2pop2-2.c: New test.
> ---
> gcc/config/i386/i386.cc | 24 ++-
> .../gcc.target/i386/apx-push2pop2-2.c | 24 +++
> 2 files changed, 42 insertions(+), 6 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> index a4e12602f70..46f238651a6 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -6802,16 +6802,24 @@ get_probe_interval (void)
>
> #define SPLIT_STACK_AVAILABLE 256
>
> -/* Helper function to determine whether push2/pop2 can be used in prologue or
> - epilogue for register save/restore. */
> +/* Return true if push2/pop2 can be generated. */
> +
> static bool
> -ix86_pro_and_epilogue_can_use_push2pop2 (int nregs)
> +ix86_can_use_push2pop2 (void)
> {
>/* Use push2/pop2 only if the incoming stack is 16-byte aligned. */
>unsigned int incoming_stack_boundary
> = (crtl->parm_stack_boundary > ix86_incoming_stack_boundary
> ? crtl->parm_stack_boundary : ix86_incoming_stack_boundary);
> - if (incoming_stack_boundary % 128 != 0)
> + return incoming_stack_boundary % 128 == 0;
> +}
> +
> +/* Helper function to determine whether push2/pop2 can be used in prologue or
> + epilogue for register save/restore. */
> +static bool
> +ix86_pro_and_epilogue_can_use_push2pop2 (int nregs)
> +{
> + if (!ix86_can_use_push2pop2 ())
> return false;
>int aligned = cfun->machine->fs.sp_offset % 16 == 0;
>return TARGET_APX_PUSH2POP2
> @@ -7401,7 +7409,9 @@ ix86_emit_save_regs (void)
>int regno;
>rtx_insn *insn;
>
> - if (!TARGET_APX_PUSH2POP2 || cfun->machine->func_type != TYPE_NORMAL)
> + if (!TARGET_APX_PUSH2POP2
> + || !ix86_can_use_push2pop2 ()
> + || cfun->machine->func_type != TYPE_NORMAL)
> {
>for (regno = FIRST_PSEUDO_REGISTER - 1; regno >= 0; regno--)
> if (GENERAL_REGNO_P (regno) && ix86_save_reg (regno, true, true))
> @@ -10039,7 +10049,9 @@ ix86_expand_epilogue (int style)
> m->fs.cfa_reg == stack_pointer_rtx);
> }
>
> - if (TARGET_APX_PUSH2POP2 && m->func_type == TYPE_NORMAL)
> + if (TARGET_APX_PUSH2POP2
> + && ix86_can_use_push2pop2 ()
> + && m->func_type == TYPE_NORMAL)
> ix86_emit_restore_regs_using_pop2 ();
>else
> ix86_emit_restore_regs_using_pop (TARGET_APX_PPX);
> diff --git a/gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
> b/gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
> new file mode 100644
> index 000..975a6212b30
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
> @@ -0,0 +1,24 @@
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-O2 -mpreferred-stack-boundary=3 -mapx-features=push2pop2
> -fomit-frame-pointer" } */
> +
> +extern int bar (int);
> +
> +void foo ()
> +{
> + int a,b,c,d,e,f,i;
> + a = bar (5);
> + b = bar (a);
> + c = bar (b);
> + d = bar (c);
> + e = bar (d);
> + f = bar (e);
> + for (i = 1; i < 10; i++)
> + {
> +a += bar (a + i) + bar (b + i) +
> + bar (c + i) + bar (d + i) +
> + bar (e + i) + bar (f + i);
> + }
> +}
> +
> +/* { dg-final { scan-assembler-not "push2(|p)\[\\t \]*%r" } } */
> +/* { dg-final { scan-assembler-not "pop2(|p)\[\\t \]*%r" } } */
> --
> 2.43.0
>
--
BR,
Hongtao
[PATCH] x86-64: Generate push2/pop2 only if the incoming stack is 16-byte aligned
Since push2/pop2 requires 16-byte stack alignment, don't generate them
if the incoming stack isn't 16-byte aligned.
gcc/
PR target/113912
* config/i386/i386.cc (ix86_can_use_push2pop2): New.
(ix86_pro_and_epilogue_can_use_push2pop2): Use it.
(ix86_emit_save_regs): Don't generate push2 if
ix86_can_use_push2pop2 return false.
(ix86_expand_epilogue): Don't generate pop2 if
ix86_can_use_push2pop2 return false.
gcc/testsuite/
PR target/113912
* gcc.target/i386/apx-push2pop2-2.c: New test.
---
gcc/config/i386/i386.cc | 24 ++-
.../gcc.target/i386/apx-push2pop2-2.c | 24 +++
2 files changed, 42 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index a4e12602f70..46f238651a6 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -6802,16 +6802,24 @@ get_probe_interval (void)
#define SPLIT_STACK_AVAILABLE 256
-/* Helper function to determine whether push2/pop2 can be used in prologue or
- epilogue for register save/restore. */
+/* Return true if push2/pop2 can be generated. */
+
static bool
-ix86_pro_and_epilogue_can_use_push2pop2 (int nregs)
+ix86_can_use_push2pop2 (void)
{
/* Use push2/pop2 only if the incoming stack is 16-byte aligned. */
unsigned int incoming_stack_boundary
= (crtl->parm_stack_boundary > ix86_incoming_stack_boundary
? crtl->parm_stack_boundary : ix86_incoming_stack_boundary);
- if (incoming_stack_boundary % 128 != 0)
+ return incoming_stack_boundary % 128 == 0;
+}
+
+/* Helper function to determine whether push2/pop2 can be used in prologue or
+ epilogue for register save/restore. */
+static bool
+ix86_pro_and_epilogue_can_use_push2pop2 (int nregs)
+{
+ if (!ix86_can_use_push2pop2 ())
return false;
int aligned = cfun->machine->fs.sp_offset % 16 == 0;
return TARGET_APX_PUSH2POP2
@@ -7401,7 +7409,9 @@ ix86_emit_save_regs (void)
int regno;
rtx_insn *insn;
- if (!TARGET_APX_PUSH2POP2 || cfun->machine->func_type != TYPE_NORMAL)
+ if (!TARGET_APX_PUSH2POP2
+ || !ix86_can_use_push2pop2 ()
+ || cfun->machine->func_type != TYPE_NORMAL)
{
for (regno = FIRST_PSEUDO_REGISTER - 1; regno >= 0; regno--)
if (GENERAL_REGNO_P (regno) && ix86_save_reg (regno, true, true))
@@ -10039,7 +10049,9 @@ ix86_expand_epilogue (int style)
m->fs.cfa_reg == stack_pointer_rtx);
}
- if (TARGET_APX_PUSH2POP2 && m->func_type == TYPE_NORMAL)
+ if (TARGET_APX_PUSH2POP2
+ && ix86_can_use_push2pop2 ()
+ && m->func_type == TYPE_NORMAL)
ix86_emit_restore_regs_using_pop2 ();
else
ix86_emit_restore_regs_using_pop (TARGET_APX_PPX);
diff --git a/gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
b/gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
new file mode 100644
index 000..975a6212b30
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/apx-push2pop2-2.c
@@ -0,0 +1,24 @@
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-O2 -mpreferred-stack-boundary=3 -mapx-features=push2pop2
-fomit-frame-pointer" } */
+
+extern int bar (int);
+
+void foo ()
+{
+ int a,b,c,d,e,f,i;
+ a = bar (5);
+ b = bar (a);
+ c = bar (b);
+ d = bar (c);
+ e = bar (d);
+ f = bar (e);
+ for (i = 1; i < 10; i++)
+ {
+a += bar (a + i) + bar (b + i) +
+ bar (c + i) + bar (d + i) +
+ bar (e + i) + bar (f + i);
+ }
+}
+
+/* { dg-final { scan-assembler-not "push2(|p)\[\\t \]*%r" } } */
+/* { dg-final { scan-assembler-not "pop2(|p)\[\\t \]*%r" } } */
--
2.43.0
