re PR fortran/45159 (Unnecessary temporaries)

2010-09-03  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/45159
	* dependency.c (gfc_deb_compare_expr):  Compare equal for equal
	arglists for pure user functions, or for those intrinsic
	functions which are also pure.
	* intrinsics.c (add_conv):  Mark conversion functions as pure.
	(add_char_conversions):  Likewise.

2010-09-03  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/45159
	* gfortran.dg/dependency_34.f90:  New test.

From-SVN: r163834

gcc/fortran/ChangeLog

@@ -1,3 +1,12 @@
+2010-09-03  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/45159
+	* dependency.c (gfc_deb_compare_expr):  Compare equal for equal
+	arglists for pure user functions, or for those intrinsic
+	functions which are also pure.
+	* intrinsics.c (add_conv):  Mark conversion functions as pure.
+	(add_char_conversions):  Likewise.
+
 2010-09-03  Daniel Kraft  <d@domob.eu>
 
 	PR fortran/34162

gcc/fortran/dependency.c

@@ -353,39 +353,32 @@ gfc_dep_compare_expr (gfc_expr *e1, gfc_expr *e2)
       return -2;
 
     case EXPR_FUNCTION:
-      /* We can only compare calls to the same intrinsic function.  */
-      if (e1->value.function.isym == 0 || e2->value.function.isym == 0
-	  || e1->value.function.isym != e2->value.function.isym)
+
+      /* PURE functions can be compared for argument equality.  */
+      if ((e1->value.function.esym && e2->value.function.esym
+	   && e1->value.function.esym == e2->value.function.esym
+	   && e1->value.function.esym->result->attr.pure)
+	  || (e1->value.function.isym && e2->value.function.isym
+	      && e1->value.function.isym == e2->value.function.isym
+	      && e1->value.function.isym->pure))
+	{
+	  args1 = e1->value.function.actual;
+	  args2 = e2->value.function.actual;
+
+	  /* Compare the argument lists for equality.  */
+	  while (args1 && args2)
+	    {
+	      if (gfc_dep_compare_expr (args1->expr, args2->expr) != 0)
+		return -2;
+	      args1 = args1->next;
+	      args2 = args2->next;
+	    }
+	  return (args1 || args2) ? -2 : 0;
+	}
+      else
 	return -2;
+      break;
 
-      args1 = e1->value.function.actual;
-      args2 = e2->value.function.actual;
-
-      /* We should list the "constant" intrinsic functions.  Those
-	 without side-effects that provide equal results given equal
-	 argument lists.  */
-      switch (e1->value.function.isym->id)
-	{
-
-	case GFC_ISYM_REAL:
-	case GFC_ISYM_LOGICAL:
-	case GFC_ISYM_DBLE:
-	  break;
-
-	default:
-	  return -2;
-	}
-
-      /* Compare the argument lists for equality.  */
-      while (args1 && args2)
-	{
-	  if (gfc_dep_compare_expr (args1->expr, args2->expr) != 0)
-	    return -2;
-	  args1 = args1->next;
-	  args2 = args2->next;
-	}
-      return (args1 || args2) ? -2 : 0;
-      
     default:
       return -2;
     }

gcc/fortran/intrinsic.c

@@ -3060,6 +3060,7 @@ add_conv (bt from_type, int from_kind, bt to_type, int to_kind, int standard)
   sym->simplify.cc = gfc_convert_constant;
   sym->standard = standard;
   sym->elemental = 1;
+  sym->pure = 1;
   sym->conversion = 1;
   sym->ts = to;
   sym->id = GFC_ISYM_CONVERSION;
@@ -3210,6 +3211,7 @@ add_char_conversions (void)
 	char_conversions[n].simplify.cc = gfc_convert_char_constant;
 	char_conversions[n].standard = GFC_STD_F2003;
 	char_conversions[n].elemental = 1;
+	char_conversions[n].pure = 1;
 	char_conversions[n].conversion = 0;
 	char_conversions[n].ts = to;
 	char_conversions[n].id = GFC_ISYM_CONVERSION;

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2010-09-03  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/45159
+	* gfortran.dg/dependency_34.f90:  New test.
+
 2010-09-03  Steve Ellcey  <sje@cup.hp.com>
 
 	* gcc.dg/torture/pr44806.c: Add -std=c99 to access uint32_t.

gcc/testsuite/gfortran.dg/dependency_34.f90

@@ -0,0 +1,22 @@
+! { dg-do compile }
+! { dg-options "-Warray-temporaries" }
+module foo
+  implicit none
+contains
+  integer pure  function bar(i,j)
+    integer, intent(in) :: i,j
+    bar = 3 - i + 1 * abs(i) + j
+  end function bar
+end module foo
+
+program main
+  use foo
+  implicit none
+  real a(10)
+  integer :: i
+  read (*,*) a, i
+  a(i:abs(i)) = a(i:abs(i))
+  a(bar(i,i+2):2) = a(bar(i,i+2):2)
+  a(int(i,kind=2):5) = a(int(i,kind=2)+1:6)
+end program main
+! { dg-final { cleanup-modules "foo" } }