[PATCH] Fix another ICE with complex assignment (PR middle-end/83608)

[Jakub Jelinek]

Hi!

The comment on convert_modes says:
   Both modes may be floating, or both integer.
but as the testcase shows, with a MEM_REF with a different mode class
than a VAR_DECL as its operand we can end up with e.g. floating point vs.
integral mode etc. and convert_modes doesn't handle those cases.

This patch uses simplify_gen_subreg in those case first.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/7.3?

2017-12-30  Jakub Jelinek  <ja...@redhat.com>

        PR middle-end/83608
        * expr.c (store_expr_with_bounds): Use simplify_gen_subreg instead of
        convert_modes if target mode has the right side, but different mode
        class.

        * g++.dg/opt/pr83608.C: New test.

--- gcc/expr.c.jj       2017-12-30 14:35:52.095877981 +0100
+++ gcc/expr.c  2017-12-30 14:36:06.268882813 +0100
@@ -5638,8 +5638,21 @@ store_expr_with_bounds (tree exp, rtx ta
   if (CONSTANT_P (temp) && GET_MODE (temp) == VOIDmode
       && TREE_CODE (exp) != ERROR_MARK
       && GET_MODE (target) != TYPE_MODE (TREE_TYPE (exp)))
-    temp = convert_modes (GET_MODE (target), TYPE_MODE (TREE_TYPE (exp)),
-                         temp, TYPE_UNSIGNED (TREE_TYPE (exp)));
+    {
+      if (GET_MODE_CLASS (GET_MODE (target))
+         != GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (exp)))
+         && GET_MODE_BITSIZE (GET_MODE (target))
+            == GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (exp))))
+       {
+         rtx t = simplify_gen_subreg (GET_MODE (target), temp,
+                                      TYPE_MODE (TREE_TYPE (exp)), 0);
+         if (t)
+           temp = t;
+       }
+      if (GET_MODE (temp) == VOIDmode)
+       temp = convert_modes (GET_MODE (target), TYPE_MODE (TREE_TYPE (exp)),
+                             temp, TYPE_UNSIGNED (TREE_TYPE (exp)));
+    }
 
   /* If value was not generated in the target, store it there.
      Convert the value to TARGET's type first if necessary and emit the
--- gcc/testsuite/g++.dg/opt/pr83608.C.jj       2017-12-30 14:36:52.323898522 
+0100
+++ gcc/testsuite/g++.dg/opt/pr83608.C  2017-12-30 14:00:12.811195532 +0100
@@ -0,0 +1,28 @@
+// PR middle-end/83608
+// { dg-do compile }
+// { dg-options "-O2" }
+
+template <typename> class B;
+template <> struct B<float>
+{
+  float foo () { return __real__ b; }
+  _Complex double 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> ();
+}

        Jakub