(simplify_set): Use rtx_equal_p to compare cc_use and its setter.

(make_extraction): Don't put a subreg around a register if it is already in
the correct mode.

From-SVN: r7322

diff --git a/gcc/combine.c b/gcc/combine.c
index c9a0b3bcd24954656486579e734d08b15ebb5352..a800a27553e7eded203f0f7b59c25fbb093e981c 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -4210,7 +4210,7 @@ simplify_set (x)
       && (cc_use = find_single_use (dest, subst_insn, &other_insn)) != 0
       && (undobuf.other_insn == 0 || other_insn == undobuf.other_insn)
       && GET_RTX_CLASS (GET_CODE (*cc_use)) == '<'
-      && XEXP (*cc_use, 0) == dest)
+      && rtx_equal_p (XEXP (*cc_use, 0), dest))
     {
       enum rtx_code old_code = GET_CODE (*cc_use);
       enum rtx_code new_code;
@@ -5071,14 +5071,20 @@ make_extraction (mode, inner, pos, pos_rtx, len,
          MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (inner);
        }
       else if (GET_CODE (inner) == REG)
-       /* We can't call gen_lowpart_for_combine here since we always want
-          a SUBREG and it would sometimes return a new hard register.  */
-       new = gen_rtx (SUBREG, tmode, inner,
-                      (WORDS_BIG_ENDIAN
-                       && GET_MODE_SIZE (inner_mode) > UNITS_PER_WORD
-                       ? ((GET_MODE_SIZE (inner_mode) - GET_MODE_SIZE (tmode))
-                          / UNITS_PER_WORD)
-                       : 0));
+       {
+         /* We can't call gen_lowpart_for_combine here since we always want
+            a SUBREG and it would sometimes return a new hard register.  */
+         if (tmode != inner_mode)
+           new = gen_rtx (SUBREG, tmode, inner,
+                          (WORDS_BIG_ENDIAN
+                           && GET_MODE_SIZE (inner_mode) > UNITS_PER_WORD
+                           ? ((GET_MODE_SIZE (inner_mode)
+                               - GET_MODE_SIZE (tmode))
+                              / UNITS_PER_WORD)
+                           : 0));
+         else
+           new = inner;
+       }
       else
        new = force_to_mode (inner, tmode,
                             len >= HOST_BITS_PER_WIDE_INT