https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112417
Bug ID: 112417
Summary: expand_builtin_return shoud check alignment for the
memory reference
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: guihaoc at gcc dot gnu.org
Target Milestone: ---
//test.c
void * foo (void * p)
{
if (p)
__builtin_return (p);
}
when compiling it with mno-vsx on ppc64, it generates 16-byte aligned vector
load instructions for the memory reference which is 1-byte aligned.
(insn 28 27 30 4 (set (reg:V4SF 66 2)
(mem:V4SF (plus:DI (reg/v/f:DI 118 [ p ])
(reg:DI 120)) [0 S16 A8])) "test4.c":4:5 1676
{*altivec_movv4sf}
It's unsafe as 16-byte aligned vector load instuction does an "AND -16" on the
memory address by itself. I think expand_builtin_return should check the
alignment and call misaligned_mem_ref expand to load the memory reference.
