gcc: xtensa: fix PR target/108919

gcc/
	PR target/108919

	* config/xtensa/xtensa-protos.h
       	(xtensa_prepare_expand_call): Rename to xtensa_expand_call.
	* config/xtensa/xtensa.cc (xtensa_prepare_expand_call): Rename
	to xtensa_expand_call.
	(xtensa_expand_call): Emit the call and add a clobber expression
	for the static chain to it in case of windowed ABI.
	* config/xtensa/xtensa.md (call, call_value, sibcall)
	(sibcall_value): Call xtensa_expand_call and complete expansion
	right after that call.

gcc/testduite/
	* gcc.target/xtensa/pr108919.c: New test.
---
 gcc/config/xtensa/xtensa-protos.h          |  2 +-
 gcc/config/xtensa/xtensa.cc                | 25 +++++++++++-
 gcc/config/xtensa/xtensa.md                | 12 ++++--
 gcc/testsuite/gcc.target/xtensa/pr108919.c | 46 ++++++++++++++++++++++
 4 files changed, 79 insertions(+), 6 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/xtensa/pr108919.c

Hello, Max:

On 2023/02/25 19:01, Max Filippov wrote:

> gcc/
> 	PR target/108919
> 
> 	* config/xtensa/xtensa-protos.h
>        	(xtensa_prepare_expand_call): Rename to xtensa_expand_call.
> 	* config/xtensa/xtensa.cc (xtensa_prepare_expand_call): Rename
> 	to xtensa_expand_call.
> 	(xtensa_expand_call): Emit the call and add a clobber expression
> 	for the static chain to it in case of windowed ABI.
> 	* config/xtensa/xtensa.md (call, call_value, sibcall)
> 	(sibcall_value): Call xtensa_expand_call and complete expansion
> 	right after that call.
> 
> gcc/testduite/
> 	* gcc.target/xtensa/pr108919.c: New test.
> ---
>  gcc/config/xtensa/xtensa-protos.h          |  2 +-
>  gcc/config/xtensa/xtensa.cc                | 25 +++++++++++-
>  gcc/config/xtensa/xtensa.md                | 12 ++++--
>  gcc/testsuite/gcc.target/xtensa/pr108919.c | 46 ++++++++++++++++++++++
>  4 files changed, 79 insertions(+), 6 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/xtensa/pr108919.c
> 
> diff --git a/gcc/config/xtensa/xtensa-protos.h b/gcc/config/xtensa/xtensa-protos.h
> index ecd0f0c8d108..c81cf94323ac 100644
> --- a/gcc/config/xtensa/xtensa-protos.h
> +++ b/gcc/config/xtensa/xtensa-protos.h
> @@ -53,7 +53,7 @@ extern void xtensa_expand_atomic (enum rtx_code, rtx, rtx, rtx, bool);
>  extern void xtensa_emit_loop_end (rtx_insn *, rtx *);
>  extern char *xtensa_emit_branch (bool, rtx *);
>  extern char *xtensa_emit_movcc (bool, bool, bool, rtx *);
> -extern void xtensa_prepare_expand_call (int, rtx *);
> +extern void xtensa_expand_call (int, rtx *);
>  extern char *xtensa_emit_call (int, rtx *);
>  extern char *xtensa_emit_sibcall (int, rtx *);
>  extern bool xtensa_tls_referenced_p (rtx);
> diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc
> index e52fba082550..babe7f0ebd68 100644
> --- a/gcc/config/xtensa/xtensa.cc
> +++ b/gcc/config/xtensa/xtensa.cc
> @@ -2183,8 +2183,10 @@ xtensa_emit_movcc (bool inverted, bool isfp, bool isbool, rtx *operands)
>  
>  
>  void
> -xtensa_prepare_expand_call (int callop, rtx *operands)
> +xtensa_expand_call (int callop, rtx *operands)
>  {
> +  rtx call;
> +  rtx call_insn;

;; This should be rtx_insn* rather than rtx,
-  rtx call_insn;
+  rtx_insn *call_insn;

>    rtx addr = XEXP (operands[callop], 0);
>  
>    if (flag_pic && SYMBOL_REF_P (addr)
> @@ -2202,6 +2204,27 @@ xtensa_prepare_expand_call (int callop, rtx *operands)
>  				 Pmode);
>        XEXP (operands[callop], 0) = reg;
>      }
> +
> +  call = gen_rtx_CALL (VOIDmode, operands[callop], operands[callop + 1]);
> +
> +  if (callop)
> +    call_insn = emit_call_insn (gen_rtx_SET (operands[0], call));
> +  else
> +    call_insn = emit_call_insn (call);

;; Simpler,
   call = gen_rtx_CALL (VOIDmode, operands[callop], operands[callop + 1]);
-
   if (callop)
-    call_insn = emit_call_insn (gen_rtx_SET (operands[0], call));
-  else
-    call_insn = emit_call_insn (call);
+    call = gen_rtx_SET (operands[0], call);
+  call_insn = emit_call_insn (call);

> +
> +  if (TARGET_WINDOWED_ABI)
> +    {
> +      /*
> +       * Windowed xtensa ABI specifies that static chain pointer is passed
> +       * in memory below the caller stack pointer, which means that the callee
> +       * will likely clobber it if it's a non-leaf function.
> +       * Add the clobber expression for the static chain to the function call
> +       * expression list so that it is not assumed to be live across the call.
> +       */
> +      rtx clob = gen_rtx_CLOBBER (Pmode, xtensa_static_chain (NULL, false));
> +      CALL_INSN_FUNCTION_USAGE (call_insn) =
> +	gen_rtx_EXPR_LIST (Pmode, clob, CALL_INSN_FUNCTION_USAGE (call_insn));
> +    }
>  }
>  
>  
> diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
> index cf25beb83d54..b60dec2447f3 100644
> --- a/gcc/config/xtensa/xtensa.md
> +++ b/gcc/config/xtensa/xtensa.md
> @@ -2333,7 +2333,8 @@
>  	 (match_operand 1 "" ""))]
>    ""
>  {
> -  xtensa_prepare_expand_call (0, operands);
> +  xtensa_expand_call (0, operands);
> +  DONE;
>  })
>  
>  (define_insn "call_internal"
> @@ -2353,7 +2354,8 @@
>  	      (match_operand 2 "" "")))]
>    ""
>  {
> -  xtensa_prepare_expand_call (1, operands);
> +  xtensa_expand_call (1, operands);
> +  DONE;
>  })
>  
>  (define_insn "call_value_internal"
> @@ -2373,7 +2375,8 @@
>  	 (match_operand 1 "" ""))]
>    "!TARGET_WINDOWED_ABI"
>  {
> -  xtensa_prepare_expand_call (0, operands);
> +  xtensa_expand_call (0, operands);
> +  DONE;
>  })
>  
>  (define_insn "sibcall_internal"
> @@ -2393,7 +2396,8 @@
>  	      (match_operand 2 "" "")))]
>    "!TARGET_WINDOWED_ABI"
>  {
> -  xtensa_prepare_expand_call (1, operands);
> +  xtensa_expand_call (1, operands);
> +  DONE;
>  })
>  
>  (define_insn "sibcall_value_internal"
> diff --git a/gcc/testsuite/gcc.target/xtensa/pr108919.c b/gcc/testsuite/gcc.target/xtensa/pr108919.c
> new file mode 100644
> index 000000000000..300b6fd10a99
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/xtensa/pr108919.c
> @@ -0,0 +1,46 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2" } */
> +
> +
> +#ifdef __XTENSA_CALL0_ABI__
> +void __xtensa_libgcc_window_spill (void)
> +{
> +}
> +#else
> +void __xtensa_libgcc_window_spill (void);
> +#endif
> +
> +__attribute__((noinline)) void h (void)
> +{
> +  __xtensa_libgcc_window_spill ();
> +}
> +
> +int f (int u, int v)
> +{
> +  int a = u;
> +  int s;
> +
> +  __attribute__((noinline,pure)) int nested1 (int b)
> +  {
> +      h();
> +      return a + b;
> +  }
> +
> +  __attribute__((noinline,pure)) int nested2 (int b)
> +  {
> +      h();
> +      return a - b;
> +  }
> +
> +  s = nested1 (v);
> +  s += nested2 (v);
> +  return s;
> +}
> +
> +int main (void)
> +{
> +  int u = 0x12345678;
> +  int v = 1;
> +
> +  return f (u, v) == 2 * u ? 0 : 1;
> +}

(I had just removed "WIP" from the set of backported patches to the esp8266/Arduino toolchain,
so I am worried that it was a bit premature, but relieved soon to find that it has nothing to do
with the CALL0 ABI...)

Hi Suwa-san,

On Sat, Feb 25, 2023 at 3:33 AM Takayuki 'January June' Suwa
<jjsuwa_sys3175@yahoo.co.jp> wrote:
> On 2023/02/25 19:01, Max Filippov wrote:
> > diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc
> > index e52fba082550..babe7f0ebd68 100644
> > --- a/gcc/config/xtensa/xtensa.cc
> > +++ b/gcc/config/xtensa/xtensa.cc
> > @@ -2183,8 +2183,10 @@ xtensa_emit_movcc (bool inverted, bool isfp, bool isbool, rtx *operands)
> >
> >
> >  void
> > -xtensa_prepare_expand_call (int callop, rtx *operands)
> > +xtensa_expand_call (int callop, rtx *operands)
> >  {
> > +  rtx call;
> > +  rtx call_insn;
>
> ;; This should be rtx_insn* rather than rtx,
> -  rtx call_insn;
> +  rtx_insn *call_insn;
>
> >    rtx addr = XEXP (operands[callop], 0);
> >
> >    if (flag_pic && SYMBOL_REF_P (addr)
> > @@ -2202,6 +2204,27 @@ xtensa_prepare_expand_call (int callop, rtx *operands)
> >                                Pmode);
> >        XEXP (operands[callop], 0) = reg;
> >      }
> > +
> > +  call = gen_rtx_CALL (VOIDmode, operands[callop], operands[callop + 1]);
> > +
> > +  if (callop)
> > +    call_insn = emit_call_insn (gen_rtx_SET (operands[0], call));
> > +  else
> > +    call_insn = emit_call_insn (call);
>
> ;; Simpler,
>    call = gen_rtx_CALL (VOIDmode, operands[callop], operands[callop + 1]);
> -
>    if (callop)
> -    call_insn = emit_call_insn (gen_rtx_SET (operands[0], call));
> -  else
> -    call_insn = emit_call_insn (call);
> +    call = gen_rtx_SET (operands[0], call);
> +  call_insn = emit_call_insn (call);

Thank you for the review!

> (I had just removed "WIP" from the set of backported patches to the esp8266/Arduino toolchain,
> so I am worried that it was a bit premature, but relieved soon to find that it has nothing to do
> with the CALL0 ABI...)

Unrelated indeed, just popped up during the recent testing.