re PR rtl-optimization/81443 (build/genrecog.o: virtual memory exhausted: Cannot allocate memory)

	PR rtl-optimization/81443
	* rtlanal.c (num_sign_bit_copies1) <SUBREG>: Do not propagate results
	from inner REGs to paradoxical SUBREGs.

From-SVN: r257724

gcc/ChangeLog

+2018-02-16  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR rtl-optimization/81443
+	* rtlanal.c (num_sign_bit_copies1) <SUBREG>: Do not propagate results
+	from inner REGs to paradoxical SUBREGs.
+
 2018-02-16  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/84399

gcc/rtlanal.c

@@ -5101,7 +5101,7 @@ num_sign_bit_copies1 (const_rtx x, scalar_int_mode mode, const_rtx known_x,
 	  if (WORD_REGISTER_OPERATIONS
 	      && load_extend_op (inner_mode) == SIGN_EXTEND
 	      && paradoxical_subreg_p (x)
-	      && (MEM_P (SUBREG_REG (x)) || REG_P (SUBREG_REG (x))))
+	      && MEM_P (SUBREG_REG (x)))
 	    return cached_num_sign_bit_copies (SUBREG_REG (x), mode,
 					       known_x, known_mode, known_ret);
 	}