[Bug ipa/92409] [10 regression] r277920 causes ICE in gcc.dg/cast-function-1.c

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92409

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think the fix is more like the following to make declare_return_variable
notice the mismatch.  That alone might not be enough but the fix should be
there.  I assume that we use a return slot only for non-registers
because those are the only valid uses of VIEW_CONVERT_EXPRs on lvalues.

Index: gcc/tree-inline.c
===================================================================
--- gcc/tree-inline.c   (revision 277955)
+++ gcc/tree-inline.c   (working copy)
@@ -3593,7 +3593,9 @@ declare_return_variable (copy_body_data
      vs. the call expression.  */
   if (modify_dest)
     caller_type = TREE_TYPE (modify_dest);
-  else
+  else if (return_slot)
+    caller_type = TREE_TYPE (return_slot);
+  else /* No LHS on the call.  */
     caller_type = TREE_TYPE (TREE_TYPE (callee));

   /* We don't need to do anything for functions that don't return anything. 
*/
@@ -3634,6 +3636,10 @@ declare_return_variable (copy_body_data
          && !DECL_GIMPLE_REG_P (result)
          && DECL_P (var))
        DECL_GIMPLE_REG_P (var) = 0;
+
+      if (!useless_type_conversion_p (callee_type, caller_type))
+       var = build1 (VIEW_CONVERT_EXPR, callee_type, var);
+
       use = NULL;
       goto done;
     }