https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104407
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |10.4
Keywords| |needs-bisection
Last reconfirmed| |2022-02-06
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Known to fail| |10.3.0, 11.1.0
Known to work| |10.2.0
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, the alignment with -g is 64 for the load but 128 without -g.
-g:
(insn 9 8 10 (set (reg/f:DI 83)
(symbol_ref:DI ("a") [flags 0x2] <var_decl 0x7f642e3a7cf0 a>))
"/app/example.cpp":4:6 -1
(nil))
(insn 10 9 11 (set (reg:TI 84)
(mem/c:TI (reg/f:DI 83) [1 a+0 S16 A64])) "/app/example.cpp":4:6 -1
(nil))
vs:
(insn 6 5 7 (set (reg/f:DI 83)
(symbol_ref:DI ("a") [flags 0x2] <var_decl 0x7f69102a2cf0 a>))
"/app/example.cpp":4:6 -1
(nil))
(insn 7 6 8 (set (reg:TI 84)
(mem/c:TI (reg/f:DI 83) [1 a+0 S16 A128])) "/app/example.cpp":4:6 -1
(nil))
The alignment in the assembly is 16 (128) for both:
.align 16
.type a, @object
.size a, 24
a:
.zero 24
It not obvious what is causing the issue though.
Here is a C++98 testcase that does not depend on C++17 features.
