https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27800
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note this is done on purpose, possibly to better handle functions with multiple
returns.
A fix is probably in gimplification of the MODIFY_EXPR
D.2774 = a != 0 ? b : c
where gimplify_cond_expr isn't told it can re-use the LHS as temporary.
That means special-casing this COND_EXPR RHS in gimplify_modify_expr_rhs
which already handles the non-register type case. It could be extended
to cover all cases which then generates the smaller
int iii (int a, int b, int c)
{
int D.2774;
if (a != 0) goto <D.2775>; else goto <D.2776>;
<D.2775>:
D.2774 = b;
goto <D.2777>;
<D.2776>:
D.2774 = c;
<D.2777>:
return D.2774;
}
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index 76221f7637d..b48c43f1471 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -5985,7 +5985,7 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p,
tree *to_p,
down into the branches. This is mandatory for ADDRESSABLE types,
since we cannot generate temporaries for such, but it saves a
copy in other cases as well. */
- if (!is_gimple_reg_type (TREE_TYPE (*from_p)))
+ if (1)
{
/* This code should mirror the code in gimplify_cond_expr. */
enum tree_code code = TREE_CODE (*expr_p);
or to cases where is_gimple_reg (*to_p).
