* simplify-rtx.c (simplify_unary_operation_1): Optimize

	(sign_extend (zero_extend ()) and
	({sign,zero}_extend (lshiftrt (ashift X (const_int I)) (const_int I))).

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@163413 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 68d8c10..fc36545 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,4 +1,11 @@
 2010-08-20  Jakub Jelinek  <jakub@redhat.com>
+           Paolo Bonzini  <bonzini@gnu.org>
+
+       * simplify-rtx.c (simplify_unary_operation_1): Optimize
+       (sign_extend (zero_extend ()) and
+       ({sign,zero}_extend (lshiftrt (ashift X (const_int I)) (const_int I))).
+
+2010-08-20  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/45353
        * sel-sched-ir.c (sel_bb_head): Return NULL even if next_nonnote_insn

diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index e3acc41..fb8ba39 100644 (file)
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -1010,15 +1010,22 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
          && GET_MODE_SIZE (mode) <= GET_MODE_SIZE (GET_MODE (XEXP (op, 0))))
        return rtl_hooks.gen_lowpart_no_emit (mode, op);
 
-      /* (sign_extend:M (sign_extend:N <X>)) is (sign_extend:M <X>).  */
-      if (GET_CODE (op) == SIGN_EXTEND)
-       return simplify_gen_unary (SIGN_EXTEND, mode, XEXP (op, 0),
-                                  GET_MODE (XEXP (op, 0)));
+      /* (sign_extend:M (sign_extend:N <X>)) is (sign_extend:M <X>).
+        (sign_extend:M (zero_extend:N <X>)) is (zero_extend:M <X>).  */
+      if (GET_CODE (op) == SIGN_EXTEND || GET_CODE (op) == ZERO_EXTEND)
+       {
+         gcc_assert (GET_MODE_BITSIZE (mode)
+                     > GET_MODE_BITSIZE (GET_MODE (op)));
+         return simplify_gen_unary (GET_CODE (op), mode, XEXP (op, 0),
+                                    GET_MODE (XEXP (op, 0)));
+       }
 
       /* (sign_extend:M (ashiftrt:N (ashift <X> (const_int I)) (const_int I)))
         is (sign_extend:M (subreg:O <X>)) if there is mode with
-        GET_MODE_BITSIZE (N) - I bits.  */
-      if (GET_CODE (op) == ASHIFTRT
+        GET_MODE_BITSIZE (N) - I bits.
+        (sign_extend:M (lshiftrt:N (ashift <X> (const_int I)) (const_int I)))
+        is similarly (zero_extend:M (subreg:O <X>)).  */
+      if ((GET_CODE (op) == ASHIFTRT || GET_CODE (op) == LSHIFTRT)
          && GET_CODE (XEXP (op, 0)) == ASHIFT
          && CONST_INT_P (XEXP (op, 1))
          && XEXP (XEXP (op, 0), 1) == XEXP (op, 1)
@@ -1027,11 +1034,15 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
          enum machine_mode tmode
            = mode_for_size (GET_MODE_BITSIZE (GET_MODE (op))
                             - INTVAL (XEXP (op, 1)), MODE_INT, 1);
+         gcc_assert (GET_MODE_BITSIZE (mode)
+                     > GET_MODE_BITSIZE (GET_MODE (op)));
          if (tmode != BLKmode)
            {
              rtx inner =
                rtl_hooks.gen_lowpart_no_emit (tmode, XEXP (XEXP (op, 0), 0));
-             return simplify_gen_unary (SIGN_EXTEND, mode, inner, tmode);
+             return simplify_gen_unary (GET_CODE (op) == ASHIFTRT
+                                        ? SIGN_EXTEND : ZERO_EXTEND,
+                                        mode, inner, tmode);
            }
        }
 
@@ -1066,6 +1077,26 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op)
        return simplify_gen_unary (ZERO_EXTEND, mode, XEXP (op, 0),
                                   GET_MODE (XEXP (op, 0)));
 
+      /* (zero_extend:M (lshiftrt:N (ashift <X> (const_int I)) (const_int I)))
+        is (zero_extend:M (subreg:O <X>)) if there is mode with
+        GET_MODE_BITSIZE (N) - I bits.  */
+      if (GET_CODE (op) == LSHIFTRT
+         && GET_CODE (XEXP (op, 0)) == ASHIFT
+         && CONST_INT_P (XEXP (op, 1))
+         && XEXP (XEXP (op, 0), 1) == XEXP (op, 1)
+         && GET_MODE_BITSIZE (GET_MODE (op)) > INTVAL (XEXP (op, 1)))
+       {
+         enum machine_mode tmode
+           = mode_for_size (GET_MODE_BITSIZE (GET_MODE (op))
+                            - INTVAL (XEXP (op, 1)), MODE_INT, 1);
+         if (tmode != BLKmode)
+           {
+             rtx inner =
+               rtl_hooks.gen_lowpart_no_emit (tmode, XEXP (XEXP (op, 0), 0));
+             return simplify_gen_unary (ZERO_EXTEND, mode, inner, tmode);
+           }
+       }
+
 #if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
       /* As we do not know which address space the pointer is refering to,
         we can do this only if the target does not support different pointer