reload.c (SMALL_REGISTER_CLASS_P): New.

* reload.c (SMALL_REGISTER_CLASS_P): New.
(push_secondary_reload, find_reusable_reload, find_reloads): Use
it instead of testing only the class size.

From-SVN: r92221

2 files changed, 21 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fee4680..41e4eba 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2004-12-15  Alexandre Oliva  <aoliva@redhat.com>
+
+	* reload.c (SMALL_REGISTER_CLASS_P): New.
+	(push_secondary_reload, find_reusable_reload, find_reloads): Use
+	it instead of testing only the class size.
+
 2004-12-15  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	PR c++/17972
diff --git a/gcc/reload.c b/gcc/reload.c
index eec1b0fc..dc45ea5 100644
--- a/gcc/reload.c
+++ b/gcc/reload.c
@@ -113,6 +113,13 @@ a register with any other reload.  */
   (CONSTANT_P (X)				\
    && GET_CODE (X) != HIGH			\
    && !targetm.cannot_force_const_mem (X))
+
+/* True if C is a non-empty register class that has too few registers
+   to be safely used as a reload target class.  */
+#define SMALL_REGISTER_CLASS_P(C) \
+  (reg_class_size [(C)] == 1 \
+   || (reg_class_size [(C)] >= 1 && CLASS_LIKELY_SPILLED_P (C)))
+
 
 /* All reloads of the current insn are recorded here.  See reload.h for
    comments.  */
@@ -443,7 +450,7 @@ push_secondary_reload (int in_p, rtx x, int opnum, int optional,
 			  == CODE_FOR_nothing))
 		|| (! in_p &&(rld[t_reload].secondary_out_icode
 			      == CODE_FOR_nothing)))
-	    && (reg_class_size[(int) t_class] == 1 || SMALL_REGISTER_CLASSES)
+	    && (SMALL_REGISTER_CLASS_P (t_class) || SMALL_REGISTER_CLASSES)
 	    && MERGABLE_RELOADS (secondary_type,
 				 rld[t_reload].when_needed,
 				 opnum, rld[t_reload].opnum))
@@ -501,7 +508,7 @@ push_secondary_reload (int in_p, rtx x, int opnum, int optional,
 	    || (! in_p && rld[s_reload].secondary_out_reload == t_reload))
 	&& ((in_p && rld[s_reload].secondary_in_icode == t_icode)
 	    || (! in_p && rld[s_reload].secondary_out_icode == t_icode))
-	&& (reg_class_size[(int) class] == 1 || SMALL_REGISTER_CLASSES)
+	&& (SMALL_REGISTER_CLASS_P (class) || SMALL_REGISTER_CLASSES)
 	&& MERGABLE_RELOADS (secondary_type, rld[s_reload].when_needed,
 			     opnum, rld[s_reload].opnum))
       {
@@ -755,7 +762,7 @@ find_reusable_reload (rtx *p_in, rtx out, enum reg_class class,
 	    || (out != 0 && MATCHES (rld[i].out, out)
 		&& (in == 0 || rld[i].in == 0 || MATCHES (rld[i].in, in))))
 	&& (rld[i].out == 0 || ! earlyclobber_operand_p (rld[i].out))
-	&& (reg_class_size[(int) class] == 1 || SMALL_REGISTER_CLASSES)
+	&& (SMALL_REGISTER_CLASS_P (class) || SMALL_REGISTER_CLASSES)
 	&& MERGABLE_RELOADS (type, rld[i].when_needed, opnum, rld[i].opnum))
       return i;
 
@@ -780,7 +787,7 @@ find_reusable_reload (rtx *p_in, rtx out, enum reg_class class,
 		&& GET_RTX_CLASS (GET_CODE (in)) == RTX_AUTOINC
 		&& MATCHES (XEXP (in, 0), rld[i].in)))
 	&& (rld[i].out == 0 || ! earlyclobber_operand_p (rld[i].out))
-	&& (reg_class_size[(int) class] == 1 || SMALL_REGISTER_CLASSES)
+	&& (SMALL_REGISTER_CLASS_P (class) || SMALL_REGISTER_CLASSES)
 	&& MERGABLE_RELOADS (type, rld[i].when_needed,
 			     opnum, rld[i].opnum))
       {
@@ -3484,7 +3491,8 @@ find_reloads (rtx insn, int replace, int ind_levels, int live_known,
 	  if (! win && ! did_match
 	      && this_alternative[i] != (int) NO_REGS
 	      && GET_MODE_SIZE (operand_mode[i]) <= UNITS_PER_WORD
-	      && reg_class_size[(int) preferred_class[i]] > 1)
+	      && reg_class_size [(int) preferred_class[i]] > 0
+	      && ! SMALL_REGISTER_CLASS_P (preferred_class[i]))
 	    {
 	      if (! reg_class_subset_p (this_alternative[i],
 					preferred_class[i]))
@@ -3540,9 +3548,9 @@ find_reloads (rtx insn, int replace, int ind_levels, int live_known,
 		  && !immune_p (recog_data.operand[j], recog_data.operand[i],
 				early_data))
 		{
-		  /* If the output is in a single-reg class,
+		  /* If the output is in a non-empty few-regs class,
 		     it's costly to reload it, so reload the input instead.  */
-		  if (reg_class_size[this_alternative[i]] == 1
+		  if (SMALL_REGISTER_CLASS_P (this_alternative[i])
 		      && (REG_P (recog_data.operand[j])
 			  || GET_CODE (recog_data.operand[j]) == SUBREG))
 		    {