https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78128
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |71002
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is
;; e_11(D)->ts.kind = _1;
(insn 20 19 0 (set (mem:SI (reg/f:DI 356) [4 e_11(D)->ts.kind+0 S4 A32])
(reg:SI 340 [ _1 ])) "t.i":39 -1
(nil))
vs.
;; _3 = BIT_FIELD_REF <MEM[(bt *)e_11(D)], 64, 0>;
(insn 21 20 0 (set (reg:DI 342 [ _3 ])
(mem:DI (reg/v/f:DI 349 [ e ]) [3 MEM[(bt *)e_11(D)]+0 S8 A64]))
"t.i":40 -1
(nil))
which use different alias sets.
Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c (revision 241509)
+++ gcc/fold-const.c (working copy)
@@ -3809,7 +3809,8 @@ make_bit_field_ref (location_t loc, tree
{
tree result, bftype;
- if (get_alias_set (inner) != get_alias_set (orig_inner))
+ if (! alias_set_subset_of (get_alias_set (orig_inner),
+ get_alias_set (inner)))
inner = fold_build2 (MEM_REF, TREE_TYPE (inner),
build_fold_addr_expr (inner),
build_int_cst
should fix it
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71002
[Bug 71002] [6 Regression] -fstrict-aliasing breaks Boost's short string
optimization implementation
