* arm.h (LEGITIMIZE_RELOAD_ADDRESS): Define.

From-SVN: r19039

gcc/ChangeLog

+Wed Apr  8 06:16:45 1998  Richard Earnshaw (rearnsha@arm.com)
+
+	* arm.h (LEGITIMIZE_RELOAD_ADDRESS): Define.
+
 Wed Apr  8 00:44:18 1998  Bernd Schmidt (crux@pool.informatik.rwth-aachen.de>
 
 	* c-lex.c (is_class_name): Delete declaration.

gcc/config/arm/arm.h

@@ -877,6 +877,59 @@ enum reg_class
   (((MODE) == HImode && TARGET_SHORT_BY_BYTES && true_regnum (X) == -1)	\
    ? GENERAL_REGS : NO_REGS)
 
+/* Try a machine-dependent way of reloading an illegitimate address
+   operand.  If we find one, push the reload and jump to WIN.  This
+   macro is used in only one place: `find_reloads_address' in reload.c.
+
+   For the ARM, we wish to handle large displacements off a base
+   register by splitting the addend across a MOV and the mem insn.
+   This can cut the number of reloads needed. */
+#define LEGITIMIZE_RELOAD_ADDRESS(X,MODE,OPNUM,TYPE,IND_LEVELS,WIN)	\
+do {									\
+  if (GET_CODE (X) == PLUS						\
+      && GET_CODE (XEXP (X, 0)) == REG					\
+      && REGNO (XEXP (X, 0)) < FIRST_PSEUDO_REGISTER			\
+      && REG_MODE_OK_FOR_BASE_P (XEXP (X, 0), MODE)			\
+      && GET_CODE (XEXP (X, 1)) == CONST_INT)				\
+    {									\
+      HOST_WIDE_INT val = INTVAL (XEXP (X, 1));				\
+      HOST_WIDE_INT low, high;						\
+									\
+      if (MODE == DImode || (TARGET_SOFT_FLOAT && MODE == DFmode))	\
+	low = ((val & 0xf) ^ 0x8) - 0x8;				\
+      else if (MODE == SImode || MODE == QImode				\
+	       || (MODE == SFmode && TARGET_SOFT_FLOAT)			\
+	       || (MODE == HImode && ! arm_arch4))			\
+	/* Need to be careful, -4096 is not a valid offset */		\
+	low = val >= 0 ? (val & 0xfff) : -((-val) & 0xfff);		\
+      else if (MODE == HImode && arm_arch4)				\
+	/* Need to be careful, -256 is not a valid offset */		\
+	low = val >= 0 ? (val & 0xff) : -((-val) & 0xff);		\
+      else if (GET_MODE_CLASS (MODE) == MODE_FLOAT			\
+	       && TARGET_HARD_FLOAT)					\
+	/* Need to be careful, -1024 is not a valid offset */		\
+	low = val >= 0 ? (val & 0x3ff) : -((-val) & 0x3ff);		\
+      else								\
+	break;								\
+									\
+      high = ((((val - low) & 0xffffffff) ^ 0x80000000) - 0x80000000);	\
+      /* Check for overflow or zero */					\
+      if (low == 0 || high == 0 || (high + low != val))			\
+	break;								\
+									\
+      /* Reload the high part into a base reg; leave the low part	\
+	 in the mem.  */						\
+      X = gen_rtx_PLUS (GET_MODE (X),					\
+			gen_rtx_PLUS (GET_MODE (X), XEXP (X, 0),	\
+				      GEN_INT (high)),			\
+			GEN_INT (low));					\
+      push_reload (XEXP (X, 0), NULL_RTX, &XEXP (X, 0), NULL_PTR,	\
+		   BASE_REG_CLASS, GET_MODE (X), VOIDmode, 0, 0,	\
+		   OPNUM, TYPE);					\
+      goto WIN;								\
+    }									\
+} while (0)
+
 /* Return the maximum number of consecutive registers
    needed to represent mode MODE in a register of class CLASS.
    ARM regs are UNITS_PER_WORD bits while FPU regs can hold any FP mode */