resolve.c (compare_case): Cleanup.

2005-01-14  Steven G. Kargl  <kargls@comcast.net>

	* resolve.c (compare_case): Cleanup.
testsuite/
	* gfortran.dg/select_1.f90: New test.
	* gfortran.dg/select_2.f90: New test.
	* gfortran.dg/select_3.f90: New test.
	* gfortran.dg/select_4.f90: New test.

From-SVN: r93640

1 files changed, 32 insertions, 65 deletions

diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 70886772d9d..4615df77e15 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -2493,85 +2493,52 @@ resolve_allocate_expr (gfc_expr * e)
 
 /* Callback function for our mergesort variant.  Determines interval
    overlaps for CASEs. Return <0 if op1 < op2, 0 for overlap, >0 for
-   op1 > op2.  Assumes we're not dealing with the default case.  */
+   op1 > op2.  Assumes we're not dealing with the default case.  
+   We have op1 = (:L), (K:L) or (K:) and op2 = (:N), (M:N) or (M:).
+   There are nine situations to check.  */
 
 static int
 compare_cases (const gfc_case * op1, const gfc_case * op2)
 {
+  int retval;
 
-  if (op1->low == NULL) /* op1 = (:N) */
+  if (op1->low == NULL) /* op1 = (:L)  */
     {
-      if (op2->low == NULL) /* op2 = (:M), so overlap.  */
-        return 0;
-
-      else if (op2->high == NULL) /* op2 = (M:) */
-        {
-	  if (gfc_compare_expr (op1->high, op2->low) < 0)
-	    return -1;  /* N < M */
-	  else
-	    return 0;
-	}
-
-      else /* op2 = (L:M) */
-        {
-	  if (gfc_compare_expr (op1->high, op2->low) < 0)
-	    return -1; /* N < L */
-	  else
-	    return 0;
-	}
+      /* op2 = (:N), so overlap.  */
+      retval = 0;
+      /* op2 = (M:) or (M:N),  L < M  */
+      if (op2->low != NULL
+	  && gfc_compare_expr (op1->high, op2->low) < 0)
+	retval = -1;
     }
-
-  else if (op1->high == NULL) /* op1 = (N:) */
+  else if (op1->high == NULL) /* op1 = (K:)  */
     {
-      if (op2->low == NULL) /* op2 = (:M)  */
-        {
-	  if (gfc_compare_expr (op1->low, op2->high) > 0)
-	    return 1; /* N > M */
-	  else
-	    return 0;
-	}
-
-      else if (op2->high == NULL) /* op2 = (M:), so overlap.  */
-        return 0;
-
-      else /* op2 = (L:M) */
-        {
-	  if (gfc_compare_expr (op1->low, op2->high) > 0)
-	    return 1; /* N > M */
-	  else
-	    return 0;
-	}
+      /* op2 = (M:), so overlap.  */
+      retval = 0;
+      /* op2 = (:N) or (M:N), K > N  */
+      if (op2->high != NULL
+	  && gfc_compare_expr (op1->low, op2->high) > 0)
+	retval = 1;
     }
-
-  else /* op1 = (N:P) */
+  else /* op1 = (K:L)  */
     {
-      if (op2->low == NULL) /* op2 = (:M)  */
-        {
-	  if (gfc_compare_expr (op1->low, op2->high) > 0)
-	    return 1; /* N > M */
-	  else
-	    return 0;
-	}
-
-      else if (op2->high == NULL) /* op2 = (M:)  */
+      if (op2->low == NULL)       /* op2 = (:N), K > N  */
+	retval = (gfc_compare_expr (op1->low, op2->high) > 0) ? 1 : 0;
+      else if (op2->high == NULL) /* op2 = (M:), L < M  */
+	retval = (gfc_compare_expr (op1->high, op2->low) < 0) ? -1 : 0;
+      else                        /* op2 = (M:N)  */
         {
+	  retval =  0;
+          /* L < M  */
 	  if (gfc_compare_expr (op1->high, op2->low) < 0)
-	    return -1; /* P < M */
-	  else
-	    return 0;
-	}
-
-      else /* op2 = (L:M) */
-        {
-	  if (gfc_compare_expr (op1->high, op2->low) < 0)
-	    return -1; /* P < L */
-
-	  if (gfc_compare_expr (op1->low, op2->high) > 0)
-	    return 1; /* N > M */
-
-	  return 0;
+	    retval =  -1;
+          /* K > N  */
+	  else if (gfc_compare_expr (op1->low, op2->high) > 0)
+	    retval =  1;
 	}
     }
+
+  return retval;
 }