diff mbox

[Fortran] PRs 60283/60543: Fix two wrong-code bugs related for implicit pure

Message ID 5325F9BB.1090201@net-b.de
State New
Headers show

Commit Message

Tobias Burnus March 16, 2014, 7:21 p.m. UTC 
This patch fixes two issues, where gfortran claims that a function is 
implicit pure, but it is not. That will cause a wrong-code optimization 
in the middle end.

First problem, cf. PR60543, is that implicit pure was not set to 0 for 
calls to impure intrinsic subroutines. (BTW: There are no impure 
intrinsic functions.) Example:

   module m
   contains
     REAL(8) FUNCTION random()
       CALL RANDOM_NUMBER(random)
     END FUNCTION random
   end module m


The second problem pops up if one adds a BLOCK ... END BLOCK around the 
random_number call after applying the patch of the PR, which just does: 
gfc_current_ns->proc_name->attr.implicit_pure = 0.

The problem is that one sets only the implicit_pure of the block to 0 
and not of the function. That's the reason that the patch became much 
longer and that I added gfc_unset_implicit_pure as new function.

Thus, the suspicion I had when reviewing the OpenACC patches turned out 
to be founded. Cf. PR60283.

Build and regtested on x86-64-gnu-linux.
OK for the trunk and for the 4.7 and 4.8 branches?

Note: I failed to create a test case.

Tobias

Comments

Tobias Burnus March 19, 2014, 8:21 p.m. UTC | #1 
Early *ping*  - I think this wrong-code GCC 4.7/4.8/4.9 issue is pretty 
severe.

Tobias Burnus wrote:
> This patch fixes two issues, where gfortran claims that a function is 
> implicit pure, but it is not. That will cause a wrong-code 
> optimization in the middle end.
>
> First problem, cf. PR60543, is that implicit pure was not set to 0 for 
> calls to impure intrinsic subroutines. (BTW: There are no impure 
> intrinsic functions.) Example:
>
>   module m
>   contains
>     REAL(8) FUNCTION random()
>       CALL RANDOM_NUMBER(random)
>     END FUNCTION random
>   end module m
>
>
> The second problem pops up if one adds a BLOCK ... END BLOCK around 
> the random_number call after applying the patch of the PR, which just 
> does: gfc_current_ns->proc_name->attr.implicit_pure = 0.
>
> The problem is that one sets only the implicit_pure of the block to 0 
> and not of the function. That's the reason that the patch became much 
> longer and that I added gfc_unset_implicit_pure as new function.
>
> Thus, the suspicion I had when reviewing the OpenACC patches turned 
> out to be founded. Cf. PR60283.
>
> Build and regtested on x86-64-gnu-linux.
> OK for the trunk and for the 4.7 and 4.8 branches?
>
> Note: I failed to create a test case.
>
> Tobias
Paul Richard Thomas March 19, 2014, 8:43 p.m. UTC | #2 
Dear Tobias,

The patch looks OK to me.  If nothing else, it offers a
rationalisation of all the lines of code that unset the attribute!

I am somewhat puzzled by "Note: I failed to create a test case",
wheras I find one at the end of the patch.  Can you explain what you
mean?

Cheers

Paul

On 19 March 2014 21:21, Tobias Burnus <burnus@net-b.de> wrote:
> Early *ping*  - I think this wrong-code GCC 4.7/4.8/4.9 issue is pretty
> severe.
>
>
> Tobias Burnus wrote:
>>
>> This patch fixes two issues, where gfortran claims that a function is
>> implicit pure, but it is not. That will cause a wrong-code optimization in
>> the middle end.
>>
>> First problem, cf. PR60543, is that implicit pure was not set to 0 for
>> calls to impure intrinsic subroutines. (BTW: There are no impure intrinsic
>> functions.) Example:
>>
>>   module m
>>   contains
>>     REAL(8) FUNCTION random()
>>       CALL RANDOM_NUMBER(random)
>>     END FUNCTION random
>>   end module m
>>
>>
>> The second problem pops up if one adds a BLOCK ... END BLOCK around the
>> random_number call after applying the patch of the PR, which just does:
>> gfc_current_ns->proc_name->attr.implicit_pure = 0.
>>
>> The problem is that one sets only the implicit_pure of the block to 0 and
>> not of the function. That's the reason that the patch became much longer and
>> that I added gfc_unset_implicit_pure as new function.
>>
>> Thus, the suspicion I had when reviewing the OpenACC patches turned out to
>> be founded. Cf. PR60283.
>>
>> Build and regtested on x86-64-gnu-linux.
>> OK for the trunk and for the 4.7 and 4.8 branches?
>>
>> Note: I failed to create a test case.
>>
>> Tobias
>
>
diff mbox

Patch

2014-03-16  Tobias Burnus  <burnus@net-b.de>

	PR fortran/60543
	PR fortran/60283
	* gfortran.h (gfc_unset_implicit_pure): New prototype.
	* resolve.c (gfc_unset_implicit_pure): New.
	(resolve_structure_cons, resolve_function,
	pure_subroutine): Use it.
	* decl.c (match_old_style_init, gfc_match_data,
	match_pointer_init, variable_decl): Ditto.
	* expr.c (gfc_check_pointer_assign): Ditto.
	* intrinsic.c (gfc_intrinsic_sub_interface): Ditto.
	* io.c (match_vtag, gfc_match_open, gfc_match_close,
	match_filepos, gfc_match_inquire, gfc_match_print,
	gfc_match_wait): Ditto.
	* match.c (gfc_match_critical, gfc_match_stopcode,
	lock_unlock_statement, sync_statement, gfc_match_allocate,
	gfc_match_deallocate): Ditto.
	* parse.c (decode_omp_directive): Ditto.
	* symbol.c (gfc_add_save): Ditto.

2014-03-16  Tobias Burnus  <burnus@net-b.de>

	PR fortran/60543
	PR fortran/60283
	* gfortran.dg/implicit_pure_4.f90: New.

diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index c7f5eed..11cded1 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -510,9 +510,7 @@  match_old_style_init (const char *name)
       free (newdata);
       return MATCH_ERROR;
     }
-
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (gfc_current_ns->proc_name);
 
   /* Mark the variable as having appeared in a data statement.  */
   if (!gfc_add_data (&sym->attr, sym->name, &sym->declared_at))
@@ -571,9 +569,7 @@  gfc_match_data (void)
       gfc_error ("DATA statement at %C is not allowed in a PURE procedure");
       return MATCH_ERROR;
     }
-
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (gfc_current_ns->proc_name);
 
   return MATCH_YES;
 
@@ -1739,6 +1735,7 @@  match_pointer_init (gfc_expr **init, int procptr)
 		 "a PURE procedure");
       return MATCH_ERROR;
     }
+  gfc_unset_implicit_pure (gfc_current_ns->proc_name);
 
   /* Match NULL() initialization.  */
   m = gfc_match_null (init);
@@ -2046,6 +2043,10 @@  variable_decl (int elem)
 	      m = MATCH_ERROR;
 	    }
 
+	  if (current_attr.flavor != FL_PARAMETER
+	      && gfc_state_stack->state != COMP_DERIVED)
+	    gfc_unset_implicit_pure (gfc_current_ns->proc_name);
+
 	  if (m != MATCH_YES)
 	    goto cleanup;
 	}
diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index fe92c53..f677204 100644
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -3704,8 +3704,7 @@  gfc_check_pointer_assign (gfc_expr *lvalue, gfc_expr *rvalue)
     }
 
   if (is_implicit_pure && gfc_impure_variable (rvalue->symtree->n.sym))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
-
+    gfc_unset_implicit_pure (gfc_current_ns->proc_name);
 
   if (gfc_has_vector_index (rvalue))
     {
diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index cd2a913..14c202d 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -2837,6 +2837,7 @@  void gfc_resolve_blocks (gfc_code *, gfc_namespace *);
 int gfc_impure_variable (gfc_symbol *);
 int gfc_pure (gfc_symbol *);
 int gfc_implicit_pure (gfc_symbol *);
+void gfc_unset_implicit_pure (gfc_symbol *);
 int gfc_elemental (gfc_symbol *);
 bool gfc_resolve_iterator (gfc_iterator *, bool, bool);
 bool find_forall_index (gfc_expr *, gfc_symbol *, int);
diff --git a/gcc/fortran/intrinsic.c b/gcc/fortran/intrinsic.c
index 3db000b..19d4620 100644
--- a/gcc/fortran/intrinsic.c
+++ b/gcc/fortran/intrinsic.c
@@ -4404,13 +4404,16 @@  gfc_intrinsic_sub_interface (gfc_code *c, int error_flag)
       return MATCH_ERROR;
     }
 
-  if (gfc_pure (NULL) && !isym->pure)
+  if (!isym->pure && gfc_pure (NULL))
     {
       gfc_error ("Subroutine call to intrinsic '%s' at %L is not PURE", name,
 		 &c->loc);
       return MATCH_ERROR;
     }
 
+  if (!isym->pure)
+    gfc_unset_implicit_pure (NULL);
+
   c->resolved_sym->attr.noreturn = isym->noreturn;
 
   return MATCH_YES;
diff --git a/gcc/fortran/io.c b/gcc/fortran/io.c
index f2593b0..8d3dc46 100644
--- a/gcc/fortran/io.c
+++ b/gcc/fortran/io.c
@@ -1305,7 +1305,8 @@  match_vtag (const io_tag *tag, gfc_expr **v)
       return MATCH_ERROR;
     }
 
-  if (gfc_pure (NULL) && gfc_impure_variable (result->symtree->n.sym))
+  bool impure = gfc_impure_variable (result->symtree->n.sym);
+  if (impure && gfc_pure (NULL))
     {
       gfc_error ("Variable %s cannot be assigned in PURE procedure at %C",
 		 tag->name);
@@ -1313,8 +1314,8 @@  match_vtag (const io_tag *tag, gfc_expr **v)
       return MATCH_ERROR;
     }
 
-  if (gfc_implicit_pure (NULL) && gfc_impure_variable (result->symtree->n.sym))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  if (impure)
+    gfc_unset_implicit_pure (NULL);
 
   *v = result;
   return MATCH_YES;
@@ -1829,8 +1830,7 @@  gfc_match_open (void)
       goto cleanup;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   warn = (open->err || open->iostat) ? true : false;
 
@@ -2242,8 +2242,7 @@  gfc_match_close (void)
       goto cleanup;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   warn = (close->iostat || close->err) ? true : false;
 
@@ -2410,8 +2409,7 @@  done:
       goto cleanup;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   new_st.op = op;
   new_st.ext.filepos = fp;
@@ -3793,8 +3791,7 @@  gfc_match_print (void)
       return MATCH_ERROR;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   return MATCH_YES;
 }
@@ -3953,8 +3950,7 @@  gfc_match_inquire (void)
 	  return MATCH_ERROR;
 	}
 
-      if (gfc_implicit_pure (NULL))
-	gfc_current_ns->proc_name->attr.implicit_pure = 0;
+      gfc_unset_implicit_pure (NULL);
 
       new_st.block = gfc_get_code (EXEC_IOLENGTH);
       terminate_io (code);
@@ -4006,8 +4002,7 @@  gfc_match_inquire (void)
       goto cleanup;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
   
   if (inquire->id != NULL && inquire->pending == NULL)
     {
@@ -4195,8 +4190,7 @@  gfc_match_wait (void)
       goto cleanup;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   new_st.op = EXEC_WAIT;
   new_st.ext.wait = wait;
diff --git a/gcc/fortran/match.c b/gcc/fortran/match.c
index 171774c..4c46094 100644
--- a/gcc/fortran/match.c
+++ b/gcc/fortran/match.c
@@ -1751,8 +1751,7 @@  gfc_match_critical (void)
       return MATCH_ERROR;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   if (!gfc_notify_std (GFC_STD_F2008, "CRITICAL statement at %C"))
     return MATCH_ERROR;
@@ -2676,8 +2675,7 @@  gfc_match_stopcode (gfc_statement st)
       goto cleanup;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   if (st == ST_STOP && gfc_find_state (COMP_CRITICAL))
     {
@@ -2814,8 +2812,7 @@  lock_unlock_statement (gfc_statement st)
       return MATCH_ERROR;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   if (gfc_option.coarray == GFC_FCOARRAY_NONE)
     {
@@ -3008,8 +3005,7 @@  sync_statement (gfc_statement st)
       return MATCH_ERROR;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   if (!gfc_notify_std (GFC_STD_F2008, "SYNC statement at %C"))
     return MATCH_ERROR;
@@ -3479,15 +3475,15 @@  gfc_match_allocate (void)
       if (gfc_check_do_variable (tail->expr->symtree))
 	goto cleanup;
 
-      if (gfc_pure (NULL) && gfc_impure_variable (tail->expr->symtree->n.sym))
+      bool impure = gfc_impure_variable (tail->expr->symtree->n.sym);
+      if (impure && gfc_pure (NULL))
 	{
 	  gfc_error ("Bad allocate-object at %C for a PURE procedure");
 	  goto cleanup;
 	}
 
-      if (gfc_implicit_pure (NULL)
-	    && gfc_impure_variable (tail->expr->symtree->n.sym))
-	gfc_current_ns->proc_name->attr.implicit_pure = 0;
+      if (impure)
+	gfc_unset_implicit_pure (NULL);
 
       if (tail->expr->ts.deferred)
 	{
@@ -3868,14 +3864,15 @@  gfc_match_deallocate (void)
 
       sym = tail->expr->symtree->n.sym;
 
-      if (gfc_pure (NULL) && gfc_impure_variable (sym))
+      bool impure = gfc_impure_variable (sym);
+      if (impure && gfc_pure (NULL))
 	{
 	  gfc_error ("Illegal allocate-object at %C for a PURE procedure");
 	  goto cleanup;
 	}
 
-      if (gfc_implicit_pure (NULL) && gfc_impure_variable (sym))
-	gfc_current_ns->proc_name->attr.implicit_pure = 0;
+      if (impure)
+	gfc_unset_implicit_pure (NULL);
 
       if (gfc_is_coarray (tail->expr)
 	  && gfc_find_state (COMP_DO_CONCURRENT))
diff --git a/gcc/fortran/parse.c b/gcc/fortran/parse.c
index d9af60e..0faf47a 100644
--- a/gcc/fortran/parse.c
+++ b/gcc/fortran/parse.c
@@ -550,8 +550,7 @@  decode_omp_directive (void)
       return ST_NONE;
     }
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 
   old_locus = gfc_current_locus;
 
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index bcdfcad..ac58167 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -1328,9 +1328,10 @@  resolve_structure_cons (gfc_expr *expr, int init)
 	}
 
       /* F2003, C1272 (3).  */
-      if (gfc_pure (NULL) && cons->expr->expr_type == EXPR_VARIABLE
-	  && (gfc_impure_variable (cons->expr->symtree->n.sym)
-	      || gfc_is_coindexed (cons->expr)))
+      bool impure = cons->expr->expr_type == EXPR_VARIABLE
+		    && (gfc_impure_variable (cons->expr->symtree->n.sym)
+			|| gfc_is_coindexed (cons->expr));
+      if (impure && gfc_pure (NULL))
 	{
 	  t = false;
 	  gfc_error ("Invalid expression in the structure constructor for "
@@ -1338,12 +1339,8 @@  resolve_structure_cons (gfc_expr *expr, int init)
 		     comp->name, &cons->expr->where);
 	}
 
-      if (gfc_implicit_pure (NULL)
-	    && cons->expr->expr_type == EXPR_VARIABLE
-	    && (gfc_impure_variable (cons->expr->symtree->n.sym)
-		|| gfc_is_coindexed (cons->expr)))
-	gfc_current_ns->proc_name->attr.implicit_pure = 0;
-
+      if (impure)
+	gfc_unset_implicit_pure (NULL);
     }
 
   return t;
@@ -3006,8 +3003,7 @@  resolve_function (gfc_expr *expr)
 	  t = false;
 	}
 
-      if (gfc_implicit_pure (NULL))
-	gfc_current_ns->proc_name->attr.implicit_pure = 0;
+      gfc_unset_implicit_pure (NULL);
     }
 
   /* Functions without the RECURSIVE attribution are not allowed to
@@ -3072,8 +3068,7 @@  pure_subroutine (gfc_code *c, gfc_symbol *sym)
     gfc_error ("Subroutine call to '%s' at %L is not PURE", sym->name,
 	       &c->loc);
 
-  if (gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  gfc_unset_implicit_pure (NULL);
 }
 
 
@@ -13927,6 +13922,33 @@  gfc_implicit_pure (gfc_symbol *sym)
 }
 
 
+void
+gfc_unset_implicit_pure (gfc_symbol *sym)
+{
+  gfc_namespace *ns;
+
+  if (sym == NULL)
+    {
+      /* Check if the current procedure is implicit_pure.  Walk up
+	 the procedure list until we find a procedure.  */
+      for (ns = gfc_current_ns; ns; ns = ns->parent)
+	{
+	  sym = ns->proc_name;
+	  if (sym == NULL)
+	    return;
+
+	  if (sym->attr.flavor == FL_PROCEDURE)
+	    break;
+	}
+    }
+
+  if (sym->attr.flavor == FL_PROCEDURE)
+    sym->attr.implicit_pure = 0;
+  else
+    sym->attr.pure = 0;
+}
+
+
 /* Test whether the current procedure is elemental or not.  */
 
 int
diff --git a/gcc/fortran/symbol.c b/gcc/fortran/symbol.c
index 6666872..19d792e 100644
--- a/gcc/fortran/symbol.c
+++ b/gcc/fortran/symbol.c
@@ -1114,8 +1114,8 @@  gfc_add_save (symbol_attribute *attr, save_state s, const char *name,
       return false;
     }
 
-  if (s == SAVE_EXPLICIT && gfc_implicit_pure (NULL))
-    gfc_current_ns->proc_name->attr.implicit_pure = 0;
+  if (s == SAVE_EXPLICIT)
+    gfc_unset_implicit_pure (NULL);
 
   if (s == SAVE_EXPLICIT && attr->save == SAVE_EXPLICIT)
     {
diff --git a/gcc/testsuite/gfortran.dg/implicit_pure_4.f90 b/gcc/testsuite/gfortran.dg/implicit_pure_4.f90
new file mode 100644
index 0000000..8563dd7
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/implicit_pure_4.f90
@@ -0,0 +1,22 @@ 
+! { dg-do compile }
+!
+! PR fortran/60543
+! PR fortran/60283
+!
+module m
+contains
+  REAL(8) FUNCTION random()
+    CALL RANDOM_NUMBER(random)
+  END FUNCTION random
+  REAL(8) FUNCTION random2()
+    block
+      block
+        block
+          CALL RANDOM_NUMBER(random2)
+        end block
+      end block
+    end block
+  END FUNCTION random2
+end module m
+
+! { dg-final { scan-module-absence "m" "IMPLICIT_PURE" } }