* simplify-rtx.c (simplify_unary_operation_1) <TRUNCATE>: Return

	new expression in the requested machine mode.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@110959 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6ffd332..ca77775 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2006-02-13  Adam Nemet  <anemet@caviumnetworks.com>
+
+       * simplify-rtx.c (simplify_unary_operation_1) <TRUNCATE>: Return
+       new expression in the requested machine mode.
+
 2006-02-13  Roger Sayle  <roger@eyesopen.com>
 
        * optabs.c (expand_abs): Don't call do_jump_by_parts_greater_rtx

diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 4cdbad7..c949dea 100644 (file)
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -609,12 +609,13 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
        return simplify_gen_unary (GET_CODE (op), mode,
                                   XEXP (XEXP (op, 0), 0), mode);
 
-      /* (truncate:SI (subreg:DI (truncate:SI X) 0)) is
-        (truncate:SI x).  */
+      /* (truncate:A (subreg:B (truncate:C X) 0)) is
+        (truncate:A X).  */
       if (GET_CODE (op) == SUBREG
          && GET_CODE (SUBREG_REG (op)) == TRUNCATE
          && subreg_lowpart_p (op))
-       return SUBREG_REG (op);
+       return simplify_gen_unary (TRUNCATE, mode, XEXP (SUBREG_REG (op), 0),
+                                  GET_MODE (XEXP (SUBREG_REG (op), 0)));
 
       /* If we know that the value is already truncated, we can
          replace the TRUNCATE with a SUBREG if TRULY_NOOP_TRUNCATION