https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111591
--- Comment #22 from Richard Biener <rguenth at gcc dot gnu.org> ---
I see the mems properly get their base adjusted:
(insn 384 383 0 (set (mem/c:V2DI (plus:DI (reg/f:DI 112 virtual-stack-vars)
(const_int 16 [0x10])) [7 MEM[(struct Vec128D.30433 *)_10]+0
S16 A128])
(reg:V2DI 616)) -1
(nil))
vs.
(insn 389 388 390 (set (reg:HI 619)
(mem/c:HI (plus:DI (reg/f:DI 112 virtual-stack-vars)
(const_int 16 [0x10])) [4 MEM[(struct Vec128D.30212
*)_10].rawD.30221[0]+0 S2 A128])) "test.cc":218:14 -1
(nil))
both are based off a fake _10. But we get alias sets 7 and 4 used here
which might be a problem.
See update_alias_info_with_stack_vars and uses of decls_to_pointers,
in particular from set_mem_attributes_minus_bitpos where we preserve
TBAA info with the rewrite. I'm not sure why that should be OK ...
(but I'm sure I must have thought of this problem back in time)
Does the following fix the testcase?
diff --git a/gcc/emit-rtl.cc b/gcc/emit-rtl.cc
index 84b6833225e..81c0a63eddc 100644
--- a/gcc/emit-rtl.cc
+++ b/gcc/emit-rtl.cc
@@ -2128,7 +2128,7 @@ set_mem_attributes_minus_bitpos (rtx ref, tree t, int
objectp,
tree *orig_base = &attrs.expr;
while (handled_component_p (*orig_base))
orig_base = &TREE_OPERAND (*orig_base, 0);
- tree aptrt = reference_alias_ptr_type (*orig_base);
+ tree aptrt = ptr_type_node;
*orig_base = build2 (MEM_REF, TREE_TYPE (*orig_base), *namep,
build_int_cst (aptrt, 0));
}
