2014-04-29 Thomas Koenig <tkoenig@gcc.gnu.org>

[pf3gnuchains/gcc-fork.git] / gcc / fortran / frontend-passes.c

diff --git a/gcc/fortran/frontend-passes.c b/gcc/fortran/frontend-passes.c
index acfb14d..05ecd20 100644 (file)
--- a/gcc/fortran/frontend-passes.c
+++ b/gcc/fortran/frontend-passes.c
@@ -442,12 +442,35 @@ cfe_expr_0 (gfc_expr **e, int *walk_subtrees,
    to insert statements as needed.  */
 
 static int
-cfe_code (gfc_code **c, int *walk_subtrees ATTRIBUTE_UNUSED,
-         void *data ATTRIBUTE_UNUSED)
+cfe_code (gfc_code **c, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
 {
   current_code = c;
   inserted_block = NULL;
   changed_statement = NULL;
+
+  /* Do not do anything inside a WHERE statement; scalar assignments, BLOCKs
+     and allocation on assigment are prohibited inside WHERE, and finally
+     masking an expression would lead to wrong-code when replacing
+
+     WHERE (a>0)
+       b = sum(foo(a) + foo(a))
+     END WHERE
+
+     with
+
+     WHERE (a > 0)
+       tmp = foo(a)
+       b = sum(tmp + tmp)
+     END WHERE
+*/
+
+  if ((*c)->op == EXEC_WHERE)
+    {
+      *walk_subtrees = 0;
+      return 0;
+    }
+  
+
   return 0;
 }