re PR target/20018 ([ia64] unable to find a register to spill in class`PR_REG')

	PR target/20018
	PR rtl-optimization/20097
	* simplify-rtx.c (simplify_relational_operation_1): Avoid creating
	BImode SUBREGs of SImode registers which confuse the ia64 backend.

From-SVN: r95461

gcc/ChangeLog

+2005-02-23  Roger Sayle  <roger@eyesopen.com>
+
+	PR target/20018
+	PR rtl-optimization/20097
+	* simplify-rtx.c (simplify_relational_operation_1): Avoid creating
+	BImode SUBREGs of SImode registers which confuse the ia64 backend.
+
 2005-02-23  David Edelsohn  <edelsohn@gnu.org>
 
 	* t-aix43 (SHLIB_INSTALL): Create directory for shared library.

gcc/simplify-rtx.c

@@ -2887,6 +2887,8 @@ simplify_relational_operation_1 (enum rtx_code code, enum machine_mode mode,
       && op1 == const0_rtx
       && GET_MODE_CLASS (mode) == MODE_INT
       && cmp_mode != VOIDmode
+      /* ??? Work-around BImode bugs in the ia64 backend.  */
+      && mode != BImode
       && cmp_mode != BImode
       && nonzero_bits (op0, cmp_mode) == 1
       && STORE_FLAG_VALUE == 1)