rtl.h (struct rtx_hooks): Add gen_lowpart_no_emit.

2005-03-21  Paolo Bonzini  <bonzini@gnu.org>

	* rtl.h (struct rtx_hooks): Add gen_lowpart_no_emit.
	* rtlhooks.c (gen_lowpart_no_emit_general): New.
	* rtlhooks-def.h (gen_lowpart_no_emit_general): Declare.
	(RTL_HOOKS_GEN_LOWPART_NO_EMIT): New.
	* simplify-rtx.c (simplify_binary_operation_1): Use it.

From-SVN: r96799

gcc/ChangeLog

+2005-03-21  Paolo Bonzini  <bonzini@gnu.org>
+
+	* rtl.h (struct rtx_hooks): Add gen_lowpart_no_emit.
+	* rtlhooks.c (gen_lowpart_no_emit_general): New.
+	* rtlhooks-def.h (gen_lowpart_no_emit_general): Declare.
+	(RTL_HOOKS_GEN_LOWPART_NO_EMIT): New.
+	* simplify-rtx.c (simplify_binary_operation_1): Use it.
+
 2005-03-21  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* builtins.c (fold_builtin_1): Take decomposed arguments of

gcc/rtl.h

@@ -2190,6 +2190,7 @@ extern void sms_schedule (FILE *);
 struct rtl_hooks
 {
   rtx (*gen_lowpart) (enum machine_mode, rtx);
+  rtx (*gen_lowpart_no_emit) (enum machine_mode, rtx);
   rtx (*reg_nonzero_bits) (rtx, enum machine_mode, rtx, enum machine_mode,
 			   unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT *);
   rtx (*reg_num_sign_bit_copies) (rtx, enum machine_mode, rtx, enum machine_mode,

gcc/rtlhooks-def.h

@@ -24,17 +24,20 @@ Boston, MA 02111-1307, USA.  */
 #include "rtl.h"
 
 #define RTL_HOOKS_GEN_LOWPART gen_lowpart_general
+#define RTL_HOOKS_GEN_LOWPART_NO_EMIT gen_lowpart_no_emit_general
 #define RTL_HOOKS_REG_NONZERO_REG_BITS reg_nonzero_bits_general
 #define RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES reg_num_sign_bit_copies_general
 
 /* The structure is defined in rtl.h.  */
 #define RTL_HOOKS_INITIALIZER {			\
   RTL_HOOKS_GEN_LOWPART,			\
+  RTL_HOOKS_GEN_LOWPART_NO_EMIT,		\
   RTL_HOOKS_REG_NONZERO_REG_BITS,		\
   RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES,		\
 }
 
 extern rtx gen_lowpart_general (enum machine_mode, rtx);
+extern rtx gen_lowpart_no_emit_general (enum machine_mode, rtx);
 extern rtx reg_nonzero_bits_general (rtx, enum machine_mode, rtx,
 				     enum machine_mode,
 				     unsigned HOST_WIDE_INT,

gcc/rtlhooks.c

@@ -79,6 +79,19 @@ gen_lowpart_general (enum machine_mode mode, rtx x)
     }
 }
 
+/* Similar to gen_lowpart, but cannot emit any instruction via
+   copy_to_reg or force_reg.  Mainly used in simplify-rtx.c.  */
+rtx
+gen_lowpart_no_emit_general (enum machine_mode mode, rtx x)
+{
+  rtx result = gen_lowpart_common (mode, x);
+  if (result)
+    return result;
+  if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode)
+    return gen_lowpart_SUBREG (mode, x);
+  return x;
+}
+
 rtx
 reg_num_sign_bit_copies_general (rtx x ATTRIBUTE_UNUSED,
 				 enum machine_mode mode ATTRIBUTE_UNUSED,

gcc/simplify-rtx.c

@@ -1704,15 +1704,7 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
 	  : const0_rtx;
 	  /* x/1 is x.  */
 	  if (trueop1 == const1_rtx)
-	    {
-	      /* Handle narrowing UDIV.  */
-	      rtx x = gen_lowpart_common (mode, op0);
-	      if (x)
-		return x;
-	      if (mode != GET_MODE (op0) && GET_MODE (op0) != VOIDmode)
-		return gen_lowpart_SUBREG (mode, op0);
-	      return op0;
-	    }
+	    return rtl_hooks.gen_lowpart_no_emit (mode, op0);
 	  /* Convert divide by power of two into shift.  */
 	  if (GET_CODE (trueop1) == CONST_INT
 	      && (val = exact_log2 (INTVAL (trueop1))) > 0)
@@ -1768,22 +1760,11 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
 	      : const0_rtx;
 	  /* x/1 is x.  */
 	  if (trueop1 == const1_rtx)
-	    {
-	      /* Handle narrowing DIV.  */
-	      rtx x = gen_lowpart_common (mode, op0);
-	      if (x)
-		return x;
-	      if (mode != GET_MODE (op0) && GET_MODE (op0) != VOIDmode)
-		return gen_lowpart_SUBREG (mode, op0);
-	      return op0;
-	    }
+	    return rtl_hooks.gen_lowpart_no_emit (mode, op0);
 	  /* x/-1 is -x.  */
 	  if (trueop1 == constm1_rtx)
 	    {
-	      rtx x = gen_lowpart_common (mode, op0);
-	      if (!x)
-		x = (mode != GET_MODE (op0) && GET_MODE (op0) != VOIDmode)
-		  ? gen_lowpart_SUBREG (mode, op0) : op0;
+	      rtx x = rtl_hooks.gen_lowpart_no_emit (mode, op0);
 	      return simplify_gen_unary (NEG, mode, x, mode);
 	    }
 	}