re PR tree-optimization/83609 (ICE in read_complex_part at gcc/expr.c:3202)

	PR middle-end/83609
	* expr.c (expand_assignment): Fix up a typo in simplify_gen_subreg
	last argument when extracting from CONCAT.  If either from_real or
	from_imag is NULL, use expansion through memory.  If result is not
	a CONCAT and simplify_gen_subreg fails, try to simplify_gen_subreg
	the parts directly to inner mode, if even that fails, use expansion
	through memory.

	* gcc.dg/pr83609.c: New test.
	* g++.dg/opt/pr83609.C: New test.

From-SVN: r256052

gcc/ChangeLog

 2018-01-01  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/83609
+	* expr.c (expand_assignment): Fix up a typo in simplify_gen_subreg
+	last argument when extracting from CONCAT.  If either from_real or
+	from_imag is NULL, use expansion through memory.  If result is not
+	a CONCAT and simplify_gen_subreg fails, try to simplify_gen_subreg
+	the parts directly to inner mode, if even that fails, use expansion
+	through memory.
+
 	PR middle-end/83623
 	* expmed.c (expand_shift_1): For 2-byte rotates by BITS_PER_UNIT,
 	check for bswap in mode rather than HImode and use that in expand_unop

gcc/expr.c

@@ -5158,7 +5158,9 @@ expand_assignment (tree to, tree from, bool nontemporal)
 					   from_mode, 0);
 		  rtx from_imag
 		    = simplify_gen_subreg (to_mode, XEXP (result, 1),
-					   from_mode, 1);
+					   from_mode, 0);
+		  if (!from_real || !from_imag)
+		    goto concat_store_slow;
 		  emit_move_insn (XEXP (to_rtx, 0), from_real);
 		  emit_move_insn (XEXP (to_rtx, 1), from_imag);
 		}
@@ -5167,14 +5169,35 @@ expand_assignment (tree to, tree from, bool nontemporal)
 		  rtx from_rtx
 		    = simplify_gen_subreg (GET_MODE (to_rtx), result,
 					   TYPE_MODE (TREE_TYPE (from)), 0);
-		  emit_move_insn (XEXP (to_rtx, 0),
-				  read_complex_part (from_rtx, false));
-		  emit_move_insn (XEXP (to_rtx, 1),
-				  read_complex_part (from_rtx, true));
+		  if (from_rtx)
+		    {
+		      emit_move_insn (XEXP (to_rtx, 0),
+				      read_complex_part (from_rtx, false));
+		      emit_move_insn (XEXP (to_rtx, 1),
+				      read_complex_part (from_rtx, true));
+		    }
+		  else
+		    {
+		      machine_mode to_mode
+			= GET_MODE_INNER (GET_MODE (to_rtx));
+		      rtx from_real
+			= simplify_gen_subreg (to_mode, result,
+					       TYPE_MODE (TREE_TYPE (from)),
+					       0);
+		      rtx from_imag
+			= simplify_gen_subreg (to_mode, result,
+					       TYPE_MODE (TREE_TYPE (from)),
+					       GET_MODE_SIZE (to_mode));
+		      if (!from_real || !from_imag)
+			goto concat_store_slow;
+		      emit_move_insn (XEXP (to_rtx, 0), from_real);
+		      emit_move_insn (XEXP (to_rtx, 1), from_imag);
+		    }
 		}
 	    }
 	  else
 	    {
+	    concat_store_slow:;
 	      rtx temp = assign_stack_temp (GET_MODE (to_rtx),
 					    GET_MODE_SIZE (GET_MODE (to_rtx)));
 	      write_complex_part (temp, XEXP (to_rtx, 0), false);

gcc/testsuite/ChangeLog

 2018-01-01  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/83609
+	* gcc.dg/pr83609.c: New test.
+	* g++.dg/opt/pr83609.C: New test.
+
 	PR middle-end/83623
 	* gcc.dg/pr83623.c: New test.
 

gcc/testsuite/g++.dg/opt/pr83609.C

+// PR middle-end/83609
+// { dg-do compile }
+// { dg-options "-O2 -fno-tree-forwprop" }
+
+template <typename> class B;
+template <> struct B<float>
+{
+  float foo () { return __real__ b; }
+  _Complex float b;
+};
+
+void bar (int);
+
+template <class T>
+void
+baz ()
+{
+  B<T> h;
+  T *a = (T *) &h;
+  a[0] = a[1] = 6;
+  h.foo () ? void () : bar (7);
+}
+
+int
+main ()
+{
+  baz<float> ();
+}

gcc/testsuite/gcc.dg/pr83609.c

+/* PR middle-end/83609 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-tree-forwprop -fno-tree-ccp -fno-tree-fre -fno-tree-pre -fno-code-hoisting" } */
+
+#if __SIZEOF_LONG_LONG__ == 2 * __SIZEOF_FLOAT__
+_Complex float
+foo (void)
+{
+  _Complex float c;
+  *((unsigned long long *)&c) = 0x123456789abcdef0ULL;
+  return c;
+}
+
+int
+main ()
+{
+  union { _Complex float c; unsigned long long l; } u;
+  u.c = foo ();
+  if (u.l != 0x123456789abcdef0ULL)
+    __builtin_abort ();
+  return 0;
+}
+#else
+int
+main ()
+{
+  return 0;
+}
+#endif