(LEGITIMIZE_ADDRESS): Define nonempty.

From-SVN: r12691

diff --git a/gcc/config/sh/sh.h b/gcc/config/sh/sh.h
index 47353088d627d54731a0a28b0d02c30badd41368..8d2245453a1ae23ae68b7ae8ffa13a355994f3b4 100644 (file)
--- a/gcc/config/sh/sh.h
+++ b/gcc/config/sh/sh.h
@@ -1059,9 +1059,52 @@ extern struct rtx_def *sh_builtin_saveregs ();
    GO_IF_LEGITIMATE_ADDRESS.
 
    It is always safe for this macro to do nothing.  It exists to recognize
-   opportunities to optimize the output.  */
+   opportunities to optimize the output.
 
-#define LEGITIMIZE_ADDRESS(X,OLDX,MODE,WIN) ;
+   For the SH, if X is almost suitable for indexing, but the offset is
+   out of range, convert it into a normal form so that cse has a chance
+   of reducing the number of address registers used.  */
+
+#define LEGITIMIZE_ADDRESS(X,OLDX,MODE,WIN)                    \
+{                                                              \
+  if (GET_CODE (x) == PLUS                                     \
+      && (GET_MODE_SIZE (MODE) == 4                            \
+         || GET_MODE_SIZE (MODE) == 8)                         \
+      && GET_CODE (XEXP (X, 1)) == CONST_INT                   \
+      && BASE_REGISTER_RTX_P (XEXP (X, 0))                     \
+      && ! (TARGET_SH3E && MODE == SFmode))                    \
+    {                                                          \
+      rtx index_rtx = XEXP (X, 1);                             \
+      HOST_WIDE_INT offset = INTVAL (index_rtx), offset_base;  \
+      rtx sum;                                                 \
+                                                               \
+      GO_IF_LEGITIMATE_INDEX (MODE, index_rtx, WIN);           \
+      /* On rare occaisons, we might get an unaligned pointer  \
+        that is indexed in a way to give an aligned address.   \
+        Therefore, keep the lower two bits in offset_base.  */ \
+      /* Instead of offset_base 128..131 use 124..127, so that \
+        simple add suffices.  */                               \
+      if (offset > 127)                                                \
+       {                                                       \
+         offset_base = ((offset + 4) & ~60) - 4;               \
+       }                                                       \
+      else                                                     \
+       offset_base = offset & ~60;                             \
+      /* Sometimes the normal form does not suit DImode.  We   \
+        could avoid that by using smaller ranges, but that     \
+        would give less optimized code when SImode is
+        prevalent.  */                                         \
+      if (GET_MODE_SIZE (MODE) + offset - offset_base <= 64)   \
+       {                                                       \
+         sum = expand_binop (Pmode, add_optab, XEXP (x, 0),    \
+                             GEN_INT (offset_base), NULL_RTX, 0, \
+                             OPTAB_LIB_WIDEN);                 \
+                                                                \
+         (X) = gen_rtx (PLUS, Pmode, sum, GEN_INT (offset - offset_base)); \
+         goto WIN;                                             \
+       }                                                       \
+    }                                                          \
+}
 
 /* Go to LABEL if ADDR (a legitimate address expression)
    has an effect that depends on the machine mode it is used for.  */