* simplify-rtx.c (simplify_binary_operation) <AND>: Optimize

	(and (sign_extend X) C) into (zero_extend (and X C)).

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@93629 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index bf7f096..d148319 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,8 +1,12 @@
+2005-01-13  Roger Sayle  <roger@eyesopen.com>
+
+       * simplify-rtx.c (simplify_binary_operation) <AND>: Optimize
+       (and (sign_extend X) C) into (zero_extend (and X C)).
+
 2005-01-13  David O'Brien  <obrien@FreeBSD.org>
 
        * config/freebsd-spec.h:  Make KSE pthread lib logic the default.
 
-
 2005-01-13  Richard Henderson  <rth@redhat.com>
 
        PR target/19009

diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 0aa1e95..91df355 100644 (file)
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -1,6 +1,6 @@
 /* RTL simplification functions for GNU compiler.
    Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -1910,6 +1910,23 @@ simplify_binary_operation (enum rtx_code code, enum machine_mode mode,
              && ! side_effects_p (op0)
              && GET_MODE_CLASS (mode) != MODE_CC)
            return const0_rtx;
+
+         /* Transform (and (extend X) C) into (zero_extend (and X C)) if
+            there are no non-zero bits of C outside of X's mode.  */
+         if ((GET_CODE (op0) == SIGN_EXTEND
+              || GET_CODE (op0) == ZERO_EXTEND)
+             && GET_CODE (trueop1) == CONST_INT
+             && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT
+             && (~GET_MODE_MASK (GET_MODE (XEXP (op0, 0)))
+                 & INTVAL (trueop1)) == 0)
+           {
+             enum machine_mode imode = GET_MODE (XEXP (op0, 0));
+             tem = simplify_gen_binary (AND, imode, XEXP (op0, 0),
+                                        gen_int_mode (INTVAL (trueop1),
+                                                      imode));
+             return simplify_gen_unary (ZERO_EXTEND, mode, tem, imode);
+           }
+
          /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M,
             ((A & N) + B) & M -> (A + B) & M
             Similarly if (N & M) == 0,