[gcc r11-9243] fortran: Ignore unused args in scalarization [PR97896]

[gcc r11-9243] fortran: Ignore unused args in scalarization [PR97896]

[Mikael Morin]

https://gcc.gnu.org/g:92e549683e1f46ba419e40b12928dc8afe5dc967

commit r11-9243-g92e549683e1f46ba419e40b12928dc8afe5dc967
Author: Mikael Morin <mikael@gcc.gnu.org>
Date:   Sun Nov 7 14:39:18 2021 +0100

    fortran: Ignore unused args in scalarization [PR97896]
    
    The KIND argument of the INDEX intrinsic is a compile time constant
    that is used at compile time only to resolve to a kind-specific library
    function.  That argument is otherwise completely ignored at runtime, and there is
    no code generated for it as the library procedure has no kind argument.
    This confuses the scalarizer which expects to see every argument
    of elemental functions used when calling a procedure.
    This change removes the argument from the scalarization lists
    at the beginning of the scalarization process, so that the argument
    is completely ignored.
    This also reverts the existing workaround
    (commit d09847357b965a2c2cda063827ce362d4c9c86f2 except for its testcase).
    
            PR fortran/97896
    
    gcc/fortran/ChangeLog:
            * intrinsic.c (add_sym_4ind): Remove.
            (add_functions): Use add_sym4 instead of add_sym4ind.
            Don’t special case the index intrinsic.
            * iresolve.c (gfc_resolve_index_func): Use the individual arguments
            directly instead of the full argument list.
            * intrinsic.h (gfc_resolve_index_func): Update the declaration
            accordingly.
            * trans-decl.c (gfc_get_extern_function_decl): Don’t modify the
            list of arguments in the case of the index intrinsic.
            * trans-array.h (gfc_get_intrinsic_for_expr,
            gfc_get_proc_ifc_for_expr): New.
            * trans-array.c (gfc_get_intrinsic_for_expr,
            arg_evaluated_for_scalarization): New.
            (gfc_walk_elemental_function_args): Add intrinsic procedure
            as argument.  Count arguments.  Check arg_evaluated_for_scalarization.
            * trans-intrinsic.c (gfc_walk_intrinsic_function): Update call.
            * trans-stmt.c (get_intrinsic_for_code): New.
            (gfc_trans_call): Update call.
    
    gcc/testsuite/ChangeLog:
            * gfortran.dg/index_5.f90: New.
    
    (cherry picked from commit 68d62cb20637b2faf2c2cc1716a0786b07a6a76f)

Diff:
---
 gcc/fortran/intrinsic.c               | 48 ++++-----------------------
 gcc/fortran/intrinsic.h               |  3 +-
 gcc/fortran/iresolve.c                | 21 +++---------
 gcc/fortran/trans-array.c             | 61 ++++++++++++++++++++++++++++++++++-
 gcc/fortran/trans-array.h             |  3 ++
 gcc/fortran/trans-decl.c              | 24 +-------------
 gcc/fortran/trans-intrinsic.c         |  1 +
 gcc/fortran/trans-stmt.c              | 20 ++++++++++++
 gcc/testsuite/gfortran.dg/index_5.f90 | 23 +++++++++++++
 9 files changed, 121 insertions(+), 83 deletions(-)

diff --git a/gcc/fortran/intrinsic.c b/gcc/fortran/intrinsic.c
index f5c88d98cc9..a6a18a471e3 100644
--- a/gcc/fortran/intrinsic.c
+++ b/gcc/fortran/intrinsic.c
@@ -888,39 +888,6 @@ add_sym_4 (const char *name, gfc_isym_id id, enum klass cl, int actual_ok, bt ty
 	   (void *) 0);
 }
 
-/* Add a symbol to the function list where the function takes 4
-   arguments and resolution may need to change the number or
-   arrangement of arguments. This is the case for INDEX, which needs
-   its KIND argument removed.  */
-
-static void
-add_sym_4ind (const char *name, gfc_isym_id id, enum klass cl, int actual_ok,
-	      bt type, int kind, int standard,
-	      bool (*check) (gfc_expr *, gfc_expr *, gfc_expr *, gfc_expr *),
-	      gfc_expr *(*simplify) (gfc_expr *, gfc_expr *, gfc_expr *,
-				     gfc_expr *),
-	      void (*resolve) (gfc_expr *, gfc_actual_arglist *),
-	      const char *a1, bt type1, int kind1, int optional1,
-	      const char *a2, bt type2, int kind2, int optional2,
-	      const char *a3, bt type3, int kind3, int optional3,
-	      const char *a4, bt type4, int kind4, int optional4 )
-{
-  gfc_check_f cf;
-  gfc_simplify_f sf;
-  gfc_resolve_f rf;
-
-  cf.f4 = check;
-  sf.f4 = simplify;
-  rf.f1m = resolve;
-
-  add_sym (name, id, cl, actual_ok, type, kind, standard, cf, sf, rf,
-	   a1, type1, kind1, optional1, INTENT_IN,
-	   a2, type2, kind2, optional2, INTENT_IN,
-	   a3, type3, kind3, optional3, INTENT_IN,
-	   a4, type4, kind4, optional4, INTENT_IN,
-	   (void *) 0);
-}
-
 
 /* Add a symbol to the subroutine list where the subroutine takes
    4 arguments.  */
@@ -2223,11 +2190,11 @@ add_functions (void)
 
   /* The resolution function for INDEX is called gfc_resolve_index_func
      because the name gfc_resolve_index is already used in resolve.c.  */
-  add_sym_4ind ("index", GFC_ISYM_INDEX, CLASS_ELEMENTAL, ACTUAL_YES,
-		BT_INTEGER, di, GFC_STD_F77,
-		gfc_check_index, gfc_simplify_index, gfc_resolve_index_func,
-		stg, BT_CHARACTER, dc, REQUIRED, ssg, BT_CHARACTER, dc, REQUIRED,
-		bck, BT_LOGICAL, dl, OPTIONAL, kind, BT_INTEGER, di, OPTIONAL);
+  add_sym_4 ("index", GFC_ISYM_INDEX, CLASS_ELEMENTAL, ACTUAL_YES,
+	     BT_INTEGER, di, GFC_STD_F77,
+	     gfc_check_index, gfc_simplify_index, gfc_resolve_index_func,
+	     stg, BT_CHARACTER, dc, REQUIRED, ssg, BT_CHARACTER, dc, REQUIRED,
+	     bck, BT_LOGICAL, dl, OPTIONAL, kind, BT_INTEGER, di, OPTIONAL);
 
   make_generic ("index", GFC_ISYM_INDEX, GFC_STD_F77);
 
@@ -4530,10 +4497,9 @@ resolve_intrinsic (gfc_intrinsic_sym *specific, gfc_expr *e)
 
   arg = e->value.function.actual;
 
-  /* Special case hacks for MIN, MAX and INDEX.  */
+  /* Special case hacks for MIN and MAX.  */
   if (specific->resolve.f1m == gfc_resolve_max
-      || specific->resolve.f1m == gfc_resolve_min
-      || specific->resolve.f1m == gfc_resolve_index_func)
+      || specific->resolve.f1m == gfc_resolve_min)
     {
       (*specific->resolve.f1m) (e, arg);
       return;
diff --git a/gcc/fortran/intrinsic.h b/gcc/fortran/intrinsic.h
index 2148f89e194..b195e0b271a 100644
--- a/gcc/fortran/intrinsic.h
+++ b/gcc/fortran/intrinsic.h
@@ -521,7 +521,8 @@ void gfc_resolve_ibits (gfc_expr *, gfc_expr *, gfc_expr *, gfc_expr *);
 void gfc_resolve_ibset (gfc_expr *, gfc_expr *, gfc_expr *);
 void gfc_resolve_image_index (gfc_expr *, gfc_expr *, gfc_expr *);
 void gfc_resolve_image_status (gfc_expr *, gfc_expr *, gfc_expr *);
-void gfc_resolve_index_func (gfc_expr *, gfc_actual_arglist *);
+void gfc_resolve_index_func (gfc_expr *, gfc_expr *, gfc_expr *, gfc_expr *,
+			     gfc_expr *);
 void gfc_resolve_ierrno (gfc_expr *);
 void gfc_resolve_ieor (gfc_expr *, gfc_expr *, gfc_expr *);
 void gfc_resolve_ichar (gfc_expr *, gfc_expr *, gfc_expr *);
diff --git a/gcc/fortran/iresolve.c b/gcc/fortran/iresolve.c
index e17fe45f080..598c0409b66 100644
--- a/gcc/fortran/iresolve.c
+++ b/gcc/fortran/iresolve.c
@@ -1276,27 +1276,16 @@ gfc_resolve_ior (gfc_expr *f, gfc_expr *i, gfc_expr *j)
 
 
 void
-gfc_resolve_index_func (gfc_expr *f, gfc_actual_arglist *a)
+gfc_resolve_index_func (gfc_expr *f, gfc_expr *str,
+			gfc_expr *sub_str ATTRIBUTE_UNUSED, gfc_expr *back,
+			gfc_expr *kind)
 {
   gfc_typespec ts;
   gfc_clear_ts (&ts);
-  gfc_expr *str, *back, *kind;
-  gfc_actual_arglist *a_sub_str, *a_back, *a_kind;
-
-  if (f->do_not_resolve_again)
-    return;
-
-  a_sub_str = a->next;
-  a_back = a_sub_str->next;
-  a_kind = a_back->next;
-
-  str = a->expr;
-  back = a_back->expr;
-  kind = a_kind->expr;
 
   f->ts.type = BT_INTEGER;
   if (kind)
-    f->ts.kind = mpz_get_si ((kind)->value.integer);
+    f->ts.kind = mpz_get_si (kind->value.integer);
   else
     f->ts.kind = gfc_default_integer_kind;
 
@@ -1311,8 +1300,6 @@ gfc_resolve_index_func (gfc_expr *f, gfc_actual_arglist *a)
 
   f->value.function.name
     = gfc_get_string ("__index_%d_i%d", str->ts.kind, f->ts.kind);
-
-  f->do_not_resolve_again = 1;
 }
 
 
diff --git a/gcc/fortran/trans-array.c b/gcc/fortran/trans-array.c
index 7eeef554c0f..ea413d80ef1 100644
--- a/gcc/fortran/trans-array.c
+++ b/gcc/fortran/trans-array.c
@@ -11185,6 +11185,59 @@ gfc_get_proc_ifc_for_expr (gfc_expr *procedure_ref)
 }
 
 
+/* Given an expression referring to an intrinsic function call,
+   return the intrinsic symbol.  */
+
+gfc_intrinsic_sym *
+gfc_get_intrinsic_for_expr (gfc_expr *call)
+{
+  if (call == NULL)
+    return NULL;
+
+  /* Normal procedure case.  */
+  if (call->expr_type == EXPR_FUNCTION)
+    return call->value.function.isym;
+  else
+    return NULL;
+}
+
+
+/* Indicates whether an argument to an intrinsic function should be used in
+   scalarization.  It is usually the case, except for some intrinsics
+   requiring the value to be constant, and using the value at compile time only.
+   As the value is not used at runtime in those cases, we don’t produce code
+   for it, and it should not be visible to the scalarizer.
+   FUNCTION is the intrinsic function being called, ACTUAL_ARG is the actual
+   argument being examined in that call, and ARG_NUM the index number
+   of ACTUAL_ARG in the list of arguments.
+   The intrinsic procedure’s dummy argument associated with ACTUAL_ARG is
+   identified using the name in ACTUAL_ARG if it is present (that is: if it’s
+   a keyword argument), otherwise using ARG_NUM.  */
+
+static bool
+arg_evaluated_for_scalarization (gfc_intrinsic_sym *function,
+				 gfc_actual_arglist &actual_arg, int arg_num)
+{
+  if (function != NULL)
+    {
+      switch (function->id)
+	{
+	  case GFC_ISYM_INDEX:
+	    if ((actual_arg.name == NULL && arg_num == 3)
+		|| (actual_arg.name != NULL
+		    && strcmp ("kind", actual_arg.name) == 0))
+	      return false;
+	  /* Fallthrough.  */
+
+	  default:
+	    break;
+	}
+    }
+
+  return true;
+}
+
+
 /* Walk the arguments of an elemental function.
    PROC_EXPR is used to check whether an argument is permitted to be absent.  If
    it is NULL, we don't do the check and the argument is assumed to be present.
@@ -11192,6 +11245,7 @@ gfc_get_proc_ifc_for_expr (gfc_expr *procedure_ref)
 
 gfc_ss *
 gfc_walk_elemental_function_args (gfc_ss * ss, gfc_actual_arglist *arg,
+				  gfc_intrinsic_sym *intrinsic_sym,
 				  gfc_symbol *proc_ifc, gfc_ss_type type)
 {
   gfc_formal_arglist *dummy_arg;
@@ -11208,10 +11262,13 @@ gfc_walk_elemental_function_args (gfc_ss * ss, gfc_actual_arglist *arg,
   else
     dummy_arg = NULL;
 
+  int arg_num = 0;
   scalar = 1;
   for (; arg; arg = arg->next)
     {
-      if (!arg->expr || arg->expr->expr_type == EXPR_NULL)
+      if (!arg->expr
+	  || arg->expr->expr_type == EXPR_NULL
+	  || !arg_evaluated_for_scalarization (intrinsic_sym, *arg, arg_num))
 	goto loop_continue;
 
       newss = gfc_walk_subexpr (head, arg->expr);
@@ -11244,6 +11301,7 @@ gfc_walk_elemental_function_args (gfc_ss * ss, gfc_actual_arglist *arg,
         }
 
 loop_continue:
+      arg_num++;
       if (dummy_arg != NULL)
 	dummy_arg = dummy_arg->next;
     }
@@ -11304,6 +11362,7 @@ gfc_walk_function_expr (gfc_ss * ss, gfc_expr * expr)
 
       ss = gfc_walk_elemental_function_args (old_ss,
 					     expr->value.function.actual,
+					     gfc_get_intrinsic_for_expr (expr),
 					     gfc_get_proc_ifc_for_expr (expr),
 					     GFC_SS_REFERENCE);
       if (ss != old_ss
diff --git a/gcc/fortran/trans-array.h b/gcc/fortran/trans-array.h
index e4d443d7118..def6f8a43a0 100644
--- a/gcc/fortran/trans-array.h
+++ b/gcc/fortran/trans-array.h
@@ -74,6 +74,8 @@ void gfc_trans_static_array_pointer (gfc_symbol *);
 
 /* Get the procedure interface for a function call.  */
 gfc_symbol *gfc_get_proc_ifc_for_expr (gfc_expr *);
+/* Get the intrinsic symbol for an intrinsic function call.  */
+gfc_intrinsic_sym *gfc_get_intrinsic_for_expr (gfc_expr *);
 /* Generate scalarization information for an expression.  */
 gfc_ss *gfc_walk_expr (gfc_expr *);
 /* Workhorse for gfc_walk_expr.  */
@@ -82,6 +84,7 @@ gfc_ss *gfc_walk_subexpr (gfc_ss *, gfc_expr *);
 gfc_ss *gfc_walk_array_ref (gfc_ss *, gfc_expr *, gfc_ref * ref);
 /* Walk the arguments of an elemental function.  */
 gfc_ss *gfc_walk_elemental_function_args (gfc_ss *, gfc_actual_arglist *,
+					  gfc_intrinsic_sym *,
 					  gfc_symbol *, gfc_ss_type);
 /* Walk an intrinsic function.  */
 gfc_ss *gfc_walk_intrinsic_function (gfc_ss *, gfc_expr *,
diff --git a/gcc/fortran/trans-decl.c b/gcc/fortran/trans-decl.c
index beea2e4d80b..95af7d93162 100644
--- a/gcc/fortran/trans-decl.c
+++ b/gcc/fortran/trans-decl.c
@@ -42,7 +42,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "trans-types.h"
 #include "trans-array.h"
 #include "trans-const.h"
-#include "intrinsic.h" 		/* For gfc_resolve_index_func.  */
 /* Only for gfc_trans_code.  Shouldn't need to include this.  */
 #include "trans-stmt.h"
 #include "gomp-constants.h"
@@ -2252,28 +2251,7 @@ module_sym:
 		{
 		  /* All specific intrinsics take less than 5 arguments.  */
 		  gcc_assert (isym->formal->next->next->next->next == NULL);
-		  if (isym->resolve.f1m == gfc_resolve_index_func)
-		    {
-		      /* gfc_resolve_index_func is special because it takes a
-			 gfc_actual_arglist instead of individual arguments.  */
-		      gfc_actual_arglist *a, *n;
-		      int i;
-		      a = gfc_get_actual_arglist();
-		      n = a;
-
-		      for (i = 0; i < 4; i++)
-			{
-			  n->next = gfc_get_actual_arglist();
-			  n = n->next;
-			}
-
-		      a->expr = &argexpr;
-		      isym->resolve.f1m (&e, a);
-		      a->expr = NULL;
-		      gfc_free_actual_arglist (a);
-		    }
-		  else
-		    isym->resolve.f4 (&e, &argexpr, NULL, NULL, NULL);
+		  isym->resolve.f4 (&e, &argexpr, NULL, NULL, NULL);
 		}
 	    }
 	}
diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
index c67a9fca46f..30042637de4 100644
--- a/gcc/fortran/trans-intrinsic.c
+++ b/gcc/fortran/trans-intrinsic.c
@@ -11172,6 +11172,7 @@ gfc_walk_intrinsic_function (gfc_ss * ss, gfc_expr * expr,
 
   if (isym->elemental)
     return gfc_walk_elemental_function_args (ss, expr->value.function.actual,
+					     expr->value.function.isym,
 					     NULL, GFC_SS_SCALAR);
 
   if (expr->rank == 0)
diff --git a/gcc/fortran/trans-stmt.c b/gcc/fortran/trans-stmt.c
index 11df1863bad..d9562d797a9 100644
--- a/gcc/fortran/trans-stmt.c
+++ b/gcc/fortran/trans-stmt.c
@@ -356,6 +356,25 @@ gfc_conv_elemental_dependencies (gfc_se * se, gfc_se * loopse,
 }
 
 
+/* Given an executable statement referring to an intrinsic function call,
+   returns the intrinsic symbol.  */
+
+static gfc_intrinsic_sym *
+get_intrinsic_for_code (gfc_code *code)
+{
+  if (code->op == EXEC_CALL)
+    {
+      gfc_intrinsic_sym * const isym = code->resolved_isym;
+      if (isym)
+	return isym;
+      else
+	return gfc_get_intrinsic_for_expr (code->expr1);
+    }
+
+  return NULL;
+}
+
+
 /* Get the interface symbol for the procedure corresponding to the given call.
    We can't get the procedure symbol directly as we have to handle the case
    of (deferred) type-bound procedures.  */
@@ -402,6 +421,7 @@ gfc_trans_call (gfc_code * code, bool dependency_check,
   ss = gfc_ss_terminator;
   if (code->resolved_sym->attr.elemental)
     ss = gfc_walk_elemental_function_args (ss, code->ext.actual,
+					   get_intrinsic_for_code (code),
 					   get_proc_ifc_for_call (code),
 					   GFC_SS_REFERENCE);
 
diff --git a/gcc/testsuite/gfortran.dg/index_5.f90 b/gcc/testsuite/gfortran.dg/index_5.f90
new file mode 100644
index 00000000000..e039455d175
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/index_5.f90
@@ -0,0 +1,23 @@
+! { dg-do compile }
+!
+! PR fortran/97896
+! An ICE occured with INDEX when the KIND argument was present
+! because of a mismatch between the number of arguments expected
+! during the scalarization process and the number of arguments actually
+! used.
+!
+! Test contributed by Harald Anlauf <anlauf@gcc.gnu.org>, based on an initial
+! submission by G. Steinmetz <gscfq@t-online.de>.
+
+program p
+  implicit none
+  logical    :: a(2)
+  integer    :: b(2)
+  integer(8) :: d(2)
+  b = index ('xyxyz','yx', back=a)
+  b = index ('xyxyz','yx', back=a, kind=4)
+  d = index ('xyxyz','yx', back=a, kind=8)
+  b = index ('xyxyz','yx', back=a, kind=8)
+  d = index ('xyxyz','yx', back=a, kind=4)
+end
+