re PR middle-end/85414 (ICE: in ix86_expand_prologue, at config/i386/i386.c:13810 with -Og -fgcse)

	PR middle-end/85414
	* simplify-rtx.c (simplify_unary_operation_1) <case SIGN_EXTEND,
	case ZERO_EXTEND>: Pass SUBREG_REG (op) rather than op to
	gen_lowpart_no_emit.

From-SVN: r259649

gcc/ChangeLog

+2018-04-25  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/85414
+	* simplify-rtx.c (simplify_unary_operation_1) <case SIGN_EXTEND,
+	case ZERO_EXTEND>: Pass SUBREG_REG (op) rather than op to
+	gen_lowpart_no_emit.
+
 2018-04-25  Sebastian Peryt  <sebastian.peryt@intel.com>
 
 	PR target/85473

gcc/expr.c

@@ -233,7 +233,10 @@ convert_move (rtx to, rtx from, int unsignedp)
       && (GET_MODE_PRECISION (subreg_promoted_mode (from))
 	  >= GET_MODE_PRECISION (to_int_mode))
       && SUBREG_CHECK_PROMOTED_SIGN (from, unsignedp))
-    from = gen_lowpart (to_int_mode, from), from_mode = to_int_mode;
+    {
+      from = gen_lowpart (to_int_mode, SUBREG_REG (from));
+      from_mode = to_int_mode;
+    }
 
   gcc_assert (GET_CODE (to) != SUBREG || !SUBREG_PROMOTED_VAR_P (to));
 

gcc/simplify-rtx.c

@@ -1484,7 +1484,7 @@ simplify_unary_operation_1 (enum rtx_code code, machine_mode mode, rtx op)
 	  && SUBREG_PROMOTED_SIGNED_P (op)
 	  && !paradoxical_subreg_p (mode, GET_MODE (SUBREG_REG (op))))
 	{
-	  temp = rtl_hooks.gen_lowpart_no_emit (mode, op);
+	  temp = rtl_hooks.gen_lowpart_no_emit (mode, SUBREG_REG (op));
 	  if (temp)
 	    return temp;
 	}
@@ -1567,7 +1567,7 @@ simplify_unary_operation_1 (enum rtx_code code, machine_mode mode, rtx op)
 	  && SUBREG_PROMOTED_UNSIGNED_P (op)
 	  && !paradoxical_subreg_p (mode, GET_MODE (SUBREG_REG (op))))
 	{
-	  temp = rtl_hooks.gen_lowpart_no_emit (mode, op);
+	  temp = rtl_hooks.gen_lowpart_no_emit (mode, SUBREG_REG (op));
 	  if (temp)
 	    return temp;
 	}