re PR rtl-optimization/34959 (23_containers/bitset/ext/15361.cc fails for MIPS n64)

gcc/
	PR rtl-optimization/34959
	* optabs.c (expand_unop): In libcall notes, give ffs, clz, ctz,
	popcount and parity rtxes the same mode as their operand.
	Truncate or extend the result to the return value's mode
	if necessary.

From-SVN: r131863

gcc/ChangeLog

 2008-01-26  Richard Sandiford  <rsandifo@nildram.co.uk>
 
+	PR rtl-optimization/34959
+	* optabs.c (expand_unop): In libcall notes, give ffs, clz, ctz,
+	popcount and parity rtxes the same mode as their operand.
+	Truncate or extend the result to the return value's mode
+	if necessary.
+
+2008-01-26  Richard Sandiford  <rsandifo@nildram.co.uk>
+
 	PR target/34981
 	* config/mips/mips-protos.h (mips_expand_call): Return an rtx.
 	* config/mips/mips.h (FIRST_PSEUDO_REGISTER): Rename FAKE_CALL_REGNO

gcc/optabs.c

@@ -3273,6 +3273,7 @@ expand_unop (enum machine_mode mode, optab unoptab, rtx op0, rtx target,
     {
       rtx insns;
       rtx value;
+      rtx eq_value;
       enum machine_mode outmode = mode;
 
       /* All of these functions return small values.  Thus we choose to
@@ -3292,8 +3293,12 @@ expand_unop (enum machine_mode mode, optab unoptab, rtx op0, rtx target,
       end_sequence ();
 
       target = gen_reg_rtx (outmode);
-      emit_libcall_block (insns, target, value,
-			  gen_rtx_fmt_e (unoptab->code, outmode, op0));
+      eq_value = gen_rtx_fmt_e (unoptab->code, mode, op0);
+      if (GET_MODE_SIZE (outmode) < GET_MODE_SIZE (mode))
+	eq_value = simplify_gen_unary (TRUNCATE, outmode, eq_value, mode);
+      else if (GET_MODE_SIZE (outmode) > GET_MODE_SIZE (mode))
+	eq_value = simplify_gen_unary (ZERO_EXTEND, outmode, eq_value, mode);
+      emit_libcall_block (insns, target, value, eq_value);
 
       return target;
     }