* [PATCH] RISC-V: Save/restore ra register correctly [PR112478]
@ 2023-11-14 14:14 Kito Cheng
2023-11-15 23:19 ` Christoph Müllner
0 siblings, 1 reply; 3+ messages in thread
From: Kito Cheng @ 2023-11-14 14:14 UTC (permalink / raw)
To: gcc-patches, kito.cheng, palmer, jeffreyalaw; +Cc: Kito Cheng
We set ra to fixed register now, but we still need to save/restore that at
prologue/epilogue if that has used.
gcc/ChangeLog:
PR target/112478
* config/riscv/riscv.cc (riscv_save_return_addr_reg_p): Check ra
is ever lived.
gcc/testsuite/gcc/ChangeLog:
PR target/112478
* riscv/pr112478.c: New.
---
gcc/config/riscv/riscv.cc | 4 ++++
gcc/testsuite/gcc.target/riscv/pr112478.c | 8 ++++++++
2 files changed, 12 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/riscv/pr112478.c
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index ecee7eb4727..f09c4066903 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -5802,6 +5802,10 @@ riscv_save_return_addr_reg_p (void)
if (riscv_far_jump_used_p ())
return true;
+ /* We need to save it if anyone has used that. */
+ if (df_regs_ever_live_p (RETURN_ADDR_REGNUM))
+ return true;
+
/* Need not to use ra for leaf when frame pointer is turned off by
option whatever the omit-leaf-frame's value. */
if (frame_pointer_needed && crtl->is_leaf
diff --git a/gcc/testsuite/gcc.target/riscv/pr112478.c b/gcc/testsuite/gcc.target/riscv/pr112478.c
new file mode 100644
index 00000000000..0bbde20b71b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/pr112478.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-ffat-lto-objects" } */
+
+void foo() {
+ asm volatile("# " : ::"ra");
+}
+
+/* { dg-final { scan-assembler "s(w|d)\[ \t\]*ra" } } */
--
2.40.1
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] RISC-V: Save/restore ra register correctly [PR112478]
2023-11-14 14:14 [PATCH] RISC-V: Save/restore ra register correctly [PR112478] Kito Cheng
@ 2023-11-15 23:19 ` Christoph Müllner
2023-11-16 11:39 ` Kito Cheng
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Müllner @ 2023-11-15 23:19 UTC (permalink / raw)
To: Kito Cheng; +Cc: gcc-patches, kito.cheng, palmer, jeffreyalaw
On Tue, Nov 14, 2023 at 3:15 PM Kito Cheng <kito.cheng@sifive.com> wrote:
>
> We set ra to fixed register now, but we still need to save/restore that at
> prologue/epilogue if that has used.
So before 71f906498ada9 $ra was neither a fixed nor a used register.
Therefore, riscv_save_reg_p returned true in the first test (not global reg,
not used_or_fixed, and ever_live_p).
After this commit, this does not happen anymore, because the test for
not used_or_fixed fails and we don't test for ever_live_p in the following.
And this patch restores this behavior.
Reviewed-by: Christoph Müllner <christoph.muellner@vrull.eu>
Tested-by: Christoph Müllner <christoph.muellner@vrull.eu>
>
> gcc/ChangeLog:
>
> PR target/112478
> * config/riscv/riscv.cc (riscv_save_return_addr_reg_p): Check ra
> is ever lived.
>
> gcc/testsuite/gcc/ChangeLog:
>
> PR target/112478
> * riscv/pr112478.c: New.
> ---
> gcc/config/riscv/riscv.cc | 4 ++++
> gcc/testsuite/gcc.target/riscv/pr112478.c | 8 ++++++++
> 2 files changed, 12 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/riscv/pr112478.c
>
> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> index ecee7eb4727..f09c4066903 100644
> --- a/gcc/config/riscv/riscv.cc
> +++ b/gcc/config/riscv/riscv.cc
> @@ -5802,6 +5802,10 @@ riscv_save_return_addr_reg_p (void)
> if (riscv_far_jump_used_p ())
> return true;
>
> + /* We need to save it if anyone has used that. */
> + if (df_regs_ever_live_p (RETURN_ADDR_REGNUM))
> + return true;
> +
> /* Need not to use ra for leaf when frame pointer is turned off by
> option whatever the omit-leaf-frame's value. */
> if (frame_pointer_needed && crtl->is_leaf
> diff --git a/gcc/testsuite/gcc.target/riscv/pr112478.c b/gcc/testsuite/gcc.target/riscv/pr112478.c
> new file mode 100644
> index 00000000000..0bbde20b71b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/pr112478.c
> @@ -0,0 +1,8 @@
> +/* { dg-do compile } */
> +/* { dg-options "-ffat-lto-objects" } */
> +
> +void foo() {
> + asm volatile("# " : ::"ra");
> +}
> +
> +/* { dg-final { scan-assembler "s(w|d)\[ \t\]*ra" } } */
> --
> 2.40.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] RISC-V: Save/restore ra register correctly [PR112478]
2023-11-15 23:19 ` Christoph Müllner
@ 2023-11-16 11:39 ` Kito Cheng
0 siblings, 0 replies; 3+ messages in thread
From: Kito Cheng @ 2023-11-16 11:39 UTC (permalink / raw)
To: Christoph Müllner; +Cc: Kito Cheng, gcc-patches, palmer, jeffreyalaw
Committed, thanks for the review and test :)
On Thu, Nov 16, 2023 at 7:19 AM Christoph Müllner
<christoph.muellner@vrull.eu> wrote:
>
> On Tue, Nov 14, 2023 at 3:15 PM Kito Cheng <kito.cheng@sifive.com> wrote:
> >
> > We set ra to fixed register now, but we still need to save/restore that at
> > prologue/epilogue if that has used.
>
> So before 71f906498ada9 $ra was neither a fixed nor a used register.
> Therefore, riscv_save_reg_p returned true in the first test (not global reg,
> not used_or_fixed, and ever_live_p).
> After this commit, this does not happen anymore, because the test for
> not used_or_fixed fails and we don't test for ever_live_p in the following.
> And this patch restores this behavior.
>
> Reviewed-by: Christoph Müllner <christoph.muellner@vrull.eu>
> Tested-by: Christoph Müllner <christoph.muellner@vrull.eu>
>
> >
> > gcc/ChangeLog:
> >
> > PR target/112478
> > * config/riscv/riscv.cc (riscv_save_return_addr_reg_p): Check ra
> > is ever lived.
> >
> > gcc/testsuite/gcc/ChangeLog:
> >
> > PR target/112478
> > * riscv/pr112478.c: New.
> > ---
> > gcc/config/riscv/riscv.cc | 4 ++++
> > gcc/testsuite/gcc.target/riscv/pr112478.c | 8 ++++++++
> > 2 files changed, 12 insertions(+)
> > create mode 100644 gcc/testsuite/gcc.target/riscv/pr112478.c
> >
> > diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
> > index ecee7eb4727..f09c4066903 100644
> > --- a/gcc/config/riscv/riscv.cc
> > +++ b/gcc/config/riscv/riscv.cc
> > @@ -5802,6 +5802,10 @@ riscv_save_return_addr_reg_p (void)
> > if (riscv_far_jump_used_p ())
> > return true;
> >
> > + /* We need to save it if anyone has used that. */
> > + if (df_regs_ever_live_p (RETURN_ADDR_REGNUM))
> > + return true;
> > +
> > /* Need not to use ra for leaf when frame pointer is turned off by
> > option whatever the omit-leaf-frame's value. */
> > if (frame_pointer_needed && crtl->is_leaf
> > diff --git a/gcc/testsuite/gcc.target/riscv/pr112478.c b/gcc/testsuite/gcc.target/riscv/pr112478.c
> > new file mode 100644
> > index 00000000000..0bbde20b71b
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.target/riscv/pr112478.c
> > @@ -0,0 +1,8 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-ffat-lto-objects" } */
> > +
> > +void foo() {
> > + asm volatile("# " : ::"ra");
> > +}
> > +
> > +/* { dg-final { scan-assembler "s(w|d)\[ \t\]*ra" } } */
> > --
> > 2.40.1
> >
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-11-16 11:39 UTC | newest]
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2023-11-14 14:14 [PATCH] RISC-V: Save/restore ra register correctly [PR112478] Kito Cheng
2023-11-15 23:19 ` Christoph Müllner
2023-11-16 11:39 ` Kito Cheng
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