diff mbox series

[2/2] arm: Add support for interrupt routines to reg_needs_saving_p

Message ID 1589468303-7890-2-git-send-email-christophe.lyon@linaro.org
State New
Headers show
Series [1/2] arm: Factorize several occurrences of the same code into reg_needs_saving_p | expand

Commit Message

Christophe Lyon May 14, 2020, 2:58 p.m. UTC 
reg_needs_saving_p is only used when dealing with non-interrupt
routines, but it makes sense to extend it to support that context too,
and make arm_compute_save_reg0_reg12_mask use it.

Save only live registers for non-leaf functions, but assume a callee
could clobber any register.

2020-05-14  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/
	* config/arm/arm.c (reg_needs_saving_p): Add support for interrupt
	routines.
	(arm_compute_save_reg0_reg12_mask): Use reg_needs_saving_p.
---
 gcc/config/arm/arm.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

Comments

Ramana Radhakrishnan May 14, 2020, 3:57 p.m. UTC | #1 
>  static bool reg_needs_saving_p (unsigned reg)
>  {
>    unsigned long func_type = arm_current_func_type ();

Ah ok , you needed it here.

Ramana
Christophe Lyon May 15, 2020, 6:36 a.m. UTC | #2 
On Thu, 14 May 2020 at 17:58, Ramana Radhakrishnan
<ramana.gcc@googlemail.com> wrote:
>
> >  static bool reg_needs_saving_p (unsigned reg)
> >  {
> >    unsigned long func_type = arm_current_func_type ();
>
> Ah ok , you needed it here.

Yes sorry.
Is this patch (2/2) OK?

Thanks,

Christophe

>
> Ramana
Ramana Radhakrishnan May 15, 2020, 9:38 a.m. UTC | #3 
On Fri, May 15, 2020 at 7:36 AM Christophe Lyon
<christophe.lyon@linaro.org> wrote:
>
> On Thu, 14 May 2020 at 17:58, Ramana Radhakrishnan
> <ramana.gcc@googlemail.com> wrote:
> >
> > >  static bool reg_needs_saving_p (unsigned reg)
> > >  {
> > >    unsigned long func_type = arm_current_func_type ();
> >
> > Ah ok , you needed it here.
>
> Yes sorry.
> Is this patch (2/2) OK?
>

This looks ok to me as long as there are no regressions and you rejig
the hunks between 1/2 and 2/2

regards
Ramana

> Thanks,
>
> Christophe
>
> >
> > Ramana
Christophe Lyon May 15, 2020, 11:03 a.m. UTC | #4 
On Fri, 15 May 2020 at 11:38, Ramana Radhakrishnan
<ramana.gcc@googlemail.com> wrote:
>
> On Fri, May 15, 2020 at 7:36 AM Christophe Lyon
> <christophe.lyon@linaro.org> wrote:
> >
> > On Thu, 14 May 2020 at 17:58, Ramana Radhakrishnan
> > <ramana.gcc@googlemail.com> wrote:
> > >
> > > >  static bool reg_needs_saving_p (unsigned reg)
> > > >  {
> > > >    unsigned long func_type = arm_current_func_type ();
> > >
> > > Ah ok , you needed it here.
> >
> > Yes sorry.
> > Is this patch (2/2) OK?
> >
>
> This looks ok to me as long as there are no regressions and you rejig
> the hunks between 1/2 and 2/2
>
Ok, thanks!

> regards
> Ramana
>
> > Thanks,
> >
> > Christophe
> >
> > >
> > > Ramana
diff mbox series

Patch

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 694c1bb..0107f50 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -4188,16 +4188,29 @@  arm_trampoline_adjust_address (rtx addr)
   return addr;
 }
 
-/* Return 1 if REG needs to be saved.   */
+/* Return 1 if REG needs to be saved. For interrupt handlers, this
+   includes call-clobbered registers too.  If this is a leaf function
+   we can just examine the registers used by the RTL, but otherwise we
+   have to assume that whatever function is called might clobber
+   anything, and so we have to save all the call-clobbered registers
+   as well.  */
 static bool reg_needs_saving_p (unsigned reg)
 {
   unsigned long func_type = arm_current_func_type ();
 
-  if (!df_regs_ever_live_p (reg)
-      || call_used_or_fixed_reg_p (reg))
-    return false;
+  if (IS_INTERRUPT (func_type))
+    if (df_regs_ever_live_p (reg)
+	/* Save call-clobbered core registers.  */
+	|| (! crtl->is_leaf && call_used_or_fixed_reg_p (reg) && reg < FIRST_VFP_REGNUM))
+      return true;
+    else
+      return false;
   else
-    return true;
+    if (!df_regs_ever_live_p (reg)
+	|| call_used_or_fixed_reg_p (reg))
+      return false;
+    else
+      return true;
 }
 
 /* Return 1 if it is possible to return using a single instruction.
@@ -20685,8 +20698,7 @@  arm_compute_save_reg0_reg12_mask (void)
 	max_reg = 12;
 
       for (reg = 0; reg <= max_reg; reg++)
-	if (df_regs_ever_live_p (reg)
-	    || (! crtl->is_leaf && call_used_or_fixed_reg_p (reg)))
+	if (reg_needs_saving_p (reg))
 	  save_reg_mask |= (1 << reg);
 
       /* Also save the pic base register if necessary.  */