Only predicate instruction arguments need to be initialized by
idef-parser. This commit removes registers from the init_list and
simplifies gen_inst_init_args() slightly.

Signed-off-by: Anton Johansson <anjo@rev.ng>
---
 target/hexagon/idef-parser/idef-parser.y    |  2 --
 target/hexagon/idef-parser/parser-helpers.c | 20 +++++++++-----------
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/target/hexagon/idef-parser/idef-parser.y b/target/hexagon/idef-parser/idef-parser.y
index cd2612eb8c..9ffb9f9699 100644
--- a/target/hexagon/idef-parser/idef-parser.y
+++ b/target/hexagon/idef-parser/idef-parser.y
@@ -233,8 +233,6 @@ code : '{' statements '}'
 argument_decl : REG
                 {
                     emit_arg(c, &@1, &$1);
-                    /* Enqueue register into initialization list */
-                    g_array_append_val(c->inst.init_list, $1);
                 }
               | PRED
                 {
diff --git a/target/hexagon/idef-parser/parser-helpers.c b/target/hexagon/idef-parser/parser-helpers.c
index bae01c2bb8..33e8f82007 100644
--- a/target/hexagon/idef-parser/parser-helpers.c
+++ b/target/hexagon/idef-parser/parser-helpers.c
@@ -1652,26 +1652,24 @@ void gen_inst(Context *c, GString *iname)
 
 
 /*
- * Initialize declared but uninitialized registers, but only for
- * non-conditional instructions
+ * Initialize declared but uninitialized instruction arguments. Only needed for
+ * predicate arguments, initialization of registers is handled by the Hexagon
+ * frontend.
  */
 void gen_inst_init_args(Context *c, YYLTYPE *locp)
 {
+    /* If init_list is NULL arguments have already been initialized */
     if (!c->inst.init_list) {
         return;
     }
 
     for (unsigned i = 0; i < c->inst.init_list->len; i++) {
         HexValue *val = &g_array_index(c->inst.init_list, HexValue, i);
-        if (val->type == REGISTER_ARG) {
-            /* Nothing to do here */
-        } else if (val->type == PREDICATE) {
-            char suffix = val->is_dotnew ? 'N' : 'V';
-            EMIT_HEAD(c, "tcg_gen_movi_i%u(P%c%c, 0);\n", val->bit_width,
-                      val->pred.id, suffix);
-        } else {
-            yyassert(c, locp, false, "Invalid arg type!");
-        }
+        yyassert(c, locp, val->type == PREDICATE,
+                 "Only predicates need to be initialized!");
+        char suffix = val->is_dotnew ? 'N' : 'V';
+        EMIT_HEAD(c, "tcg_gen_movi_i%u(P%c%c, 0);\n", val->bit_width,
+                  val->pred.id, suffix);
     }
 
     /* Free argument init list once we have initialized everything */
-- 
2.44.0

> -----Original Message-----
> From: Anton Johansson <anjo@rev.ng>
> Sent: Monday, May 6, 2024 1:31 PM
> To: qemu-devel@nongnu.org
> Cc: ale@rev.ng; ltaylorsimpson@gmail.com; bcain@quicinc.com
> Subject: [PATCH 4/4] target/hexagon: idef-parser simplify predicate init
> 
> Only predicate instruction arguments need to be initialized by
idef-parser.
> This commit removes registers from the init_list and simplifies
> gen_inst_init_args() slightly.
> 
> Signed-off-by: Anton Johansson <anjo@rev.ng>
> ---
>  target/hexagon/idef-parser/idef-parser.y    |  2 --
>  target/hexagon/idef-parser/parser-helpers.c | 20 +++++++++-----------
>  2 files changed, 9 insertions(+), 13 deletions(-)

> diff --git a/target/hexagon/idef-parser/parser-helpers.c
> b/target/hexagon/idef-parser/parser-helpers.c
> index bae01c2bb8..33e8f82007 100644
> --- a/target/hexagon/idef-parser/parser-helpers.c
> +++ b/target/hexagon/idef-parser/parser-helpers.c
> @@ -1652,26 +1652,24 @@ void gen_inst(Context *c, GString *iname)
> 
>  void gen_inst_init_args(Context *c, YYLTYPE *locp)  {
> +    /* If init_list is NULL arguments have already been initialized */
>      if (!c->inst.init_list) {
>          return;
>      }
> 
>      for (unsigned i = 0; i < c->inst.init_list->len; i++) {
>          HexValue *val = &g_array_index(c->inst.init_list, HexValue, i);
> -        if (val->type == REGISTER_ARG) {
> -            /* Nothing to do here */
> -        } else if (val->type == PREDICATE) {
> -            char suffix = val->is_dotnew ? 'N' : 'V';
> -            EMIT_HEAD(c, "tcg_gen_movi_i%u(P%c%c, 0);\n", val->bit_width,
> -                      val->pred.id, suffix);
> -        } else {
> -            yyassert(c, locp, false, "Invalid arg type!");
> -        }
> +        yyassert(c, locp, val->type == PREDICATE,
> +                 "Only predicates need to be initialized!");
> +        char suffix = val->is_dotnew ? 'N' : 'V';

Declarations should be at the beginning of the function per QEMU coding
standards.

> +        EMIT_HEAD(c, "tcg_gen_movi_i%u(P%c%c, 0);\n", val->bit_width,

Since you know this is a predicate, the bit_width will always be 32.  You
can hard-code that instead of using %u.

> +                  val->pred.id, suffix);
>      }
> 
>      /* Free argument init list once we have initialized everything */

Taylor

On 06/05/24, ltaylorsimpson@gmail.com wrote:
> 
> 
> > -----Original Message-----
> > From: Anton Johansson <anjo@rev.ng>
> > Sent: Monday, May 6, 2024 1:31 PM
> > To: qemu-devel@nongnu.org
> > Cc: ale@rev.ng; ltaylorsimpson@gmail.com; bcain@quicinc.com
> > Subject: [PATCH 4/4] target/hexagon: idef-parser simplify predicate init
> > 
> > Only predicate instruction arguments need to be initialized by
> idef-parser.
> > This commit removes registers from the init_list and simplifies
> > gen_inst_init_args() slightly.
> > 
> > Signed-off-by: Anton Johansson <anjo@rev.ng>
> > ---
> >  target/hexagon/idef-parser/idef-parser.y    |  2 --
> >  target/hexagon/idef-parser/parser-helpers.c | 20 +++++++++-----------
> >  2 files changed, 9 insertions(+), 13 deletions(-)
> 
> > diff --git a/target/hexagon/idef-parser/parser-helpers.c
> > b/target/hexagon/idef-parser/parser-helpers.c
> > index bae01c2bb8..33e8f82007 100644
> > --- a/target/hexagon/idef-parser/parser-helpers.c
> > +++ b/target/hexagon/idef-parser/parser-helpers.c
> > @@ -1652,26 +1652,24 @@ void gen_inst(Context *c, GString *iname)
> > 
> >  void gen_inst_init_args(Context *c, YYLTYPE *locp)  {
> > +    /* If init_list is NULL arguments have already been initialized */
> >      if (!c->inst.init_list) {
> >          return;
> >      }
> > 
> >      for (unsigned i = 0; i < c->inst.init_list->len; i++) {
> >          HexValue *val = &g_array_index(c->inst.init_list, HexValue, i);
> > -        if (val->type == REGISTER_ARG) {
> > -            /* Nothing to do here */
> > -        } else if (val->type == PREDICATE) {
> > -            char suffix = val->is_dotnew ? 'N' : 'V';
> > -            EMIT_HEAD(c, "tcg_gen_movi_i%u(P%c%c, 0);\n", val->bit_width,
> > -                      val->pred.id, suffix);
> > -        } else {
> > -            yyassert(c, locp, false, "Invalid arg type!");
> > -        }
> > +        yyassert(c, locp, val->type == PREDICATE,
> > +                 "Only predicates need to be initialized!");
> > +        char suffix = val->is_dotnew ? 'N' : 'V';
> 
> Declarations should be at the beginning of the function per QEMU coding
> standards.

Agh right!

>
> > +        EMIT_HEAD(c, "tcg_gen_movi_i%u(P%c%c, 0);\n", val->bit_width,
> 
> Since you know this is a predicate, the bit_width will always be 32.  You
> can hard-code that instead of using %u.

Good point, I'll add a paranoia assertion as well.

//Anton