re PR rtl-optimization/70174 (ICE at -O1 and above on x86_64-linux-gnu in…

re PR rtl-optimization/70174 (ICE at -O1 and above on x86_64-linux-gnu in gen_lowpart_general, at rtlhooks.c:63)

	PR rtl-optimization/70174
	* expmed.c (store_bit_field_using_insv): Use gen_lowpart_if_possible
	followed by gen_lowpart on force_reg instead of just gen_lowpart.

	* gcc.dg/pr70174.c: New test.

From-SVN: r234137

gcc/ChangeLog

 2016-03-11  Jakub Jelinek  <jakub@redhat.com>
 
+	PR rtl-optimization/70174
+	* expmed.c (store_bit_field_using_insv): Use gen_lowpart_if_possible
+	followed by gen_lowpart on force_reg instead of just gen_lowpart.
+
 	PR tree-optimization/70169
 	* tree-ssa-loop.c (gen_lsm_tmp_name): Handle FUNCTION_DECL and
 	LABEL_DECL like VAR_DECL.  Emit nothing instead of gcc_unreachable

gcc/expmed.c

@@ -658,24 +658,28 @@ store_bit_field_using_insv (const extraction_insn *insv, rtx op0,
     {
       if (GET_MODE_BITSIZE (GET_MODE (value)) >= bitsize)
 	{
+	  rtx tmp;
 	  /* Optimization: Don't bother really extending VALUE
 	     if it has all the bits we will actually use.  However,
 	     if we must narrow it, be sure we do it correctly.  */
 
 	  if (GET_MODE_SIZE (GET_MODE (value)) < GET_MODE_SIZE (op_mode))
 	    {
-	      rtx tmp;
-
 	      tmp = simplify_subreg (op_mode, value1, GET_MODE (value), 0);
 	      if (! tmp)
 		tmp = simplify_gen_subreg (op_mode,
 					   force_reg (GET_MODE (value),
 						      value1),
 					   GET_MODE (value), 0);
-	      value1 = tmp;
 	    }
 	  else
-	    value1 = gen_lowpart (op_mode, value1);
+	    {
+	      tmp = gen_lowpart_if_possible (op_mode, value1);
+	      if (! tmp)
+		tmp = gen_lowpart (op_mode, force_reg (GET_MODE (value),
+						       value1));
+	    }
+	  value1 = tmp;
 	}
       else if (CONST_INT_P (value))
 	value1 = gen_int_mode (INTVAL (value), op_mode);

gcc/testsuite/ChangeLog

 2016-03-11  Jakub Jelinek  <jakub@redhat.com>
 
+	PR rtl-optimization/70174
+	* gcc.dg/pr70174.c: New test.
+
 	PR tree-optimization/70169
 	* gcc.dg/pr70169.c: New test.
 

gcc/testsuite/gcc.dg/pr70174.c

+/* PR rtl-optimization/70174 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+struct S { int f : 4; } a;
+  
+void
+foo (void)
+{ 
+  a.f = foo;	/* { dg-warning "assignment makes integer from pointer without a cast" } */
+}