Convert to Pmode if needed.

[pf3gnuchains/gcc-fork.git] / gcc / explow.c

diff --git a/gcc/explow.c b/gcc/explow.c
index beeab44..984150e 100644 (file)
--- a/gcc/explow.c
+++ b/gcc/explow.c
@@ -384,18 +384,23 @@ convert_memory_address_addr_space (enum machine_mode to_mode ATTRIBUTE_UNUSED,
 
     case PLUS:
     case MULT:
-      /* For addition we can safely permute the conversion and addition
-        operation if one operand is a constant and converting the constant
-        does not change it or if one operand is a constant and we are
-        using a ptr_extend instruction  (POINTERS_EXTEND_UNSIGNED < 0).
+      /* FIXME: For addition, we used to permute the conversion and
+        addition operation only if one operand is a constant and
+        converting the constant does not change it or if one operand
+        is a constant and we are using a ptr_extend instruction
+        (POINTERS_EXTEND_UNSIGNED < 0) even if the resulting address
+        may overflow/underflow.  We relax the condition to include
+        zero-extend (POINTERS_EXTEND_UNSIGNED > 0) since the other
+        parts of the compiler depend on it.  See PR 49721.
+
         We can always safely permute them if we are making the address
         narrower.  */
       if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode)
          || (GET_CODE (x) == PLUS
              && CONST_INT_P (XEXP (x, 1))
-             && (XEXP (x, 1) == convert_memory_address_addr_space
-                                  (to_mode, XEXP (x, 1), as)
-                 || POINTERS_EXTEND_UNSIGNED < 0)))
+             && (POINTERS_EXTEND_UNSIGNED != 0
+                 || XEXP (x, 1) == convert_memory_address_addr_space
+                                       (to_mode, XEXP (x, 1), as))))
        return gen_rtx_fmt_ee (GET_CODE (x), to_mode,
                               convert_memory_address_addr_space
                                 (to_mode, XEXP (x, 0), as),