simplify-rtx.c (simplify_unary_operation_1): Return new expression in the requested...

	* simplify-rtx.c (simplify_unary_operation_1) <TRUNCATE>: Return
	new expression in the requested machine mode.

From-SVN: r110959

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6ffd3321150b5e30c6b73ed94216de0a236057fe..ca77775196a9c9160bc61fd9acb7f0bb2bc111d7 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 4cdbad754edf9ad85613df694d93867c430f33d2..c949dea1d16014a232fa62b7bdccc9e70e9aa404 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