https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81357
--- Comment #13 from Qing Zhao <qing.zhao at oracle dot com> ---
I checked the same testing case on X86, SPARC in addition to aarch64, all have
the same issue: (compile with gcc -O, the default is -m64)
***x86:
test1:
.LFB0:
.cfi_startproc
leal 1(%rdi), %eax
movl %eax, %edx
movq %rdx, d(%rip)
ret
.cfi_endproc
in the above, "movl %eax, %edx" is the insn that can be eliminated.
***SPARC:
test1:
sethi %hi(d), %g1
add %o0, 1, %o0
srl %o0, 0, %o0
jmp %o7+8
stx %o0, [%g1+%lo(d)]
in the above, "srl %o0, 0, %o0" is the insn that can be eliminated.
so, this seems a common issue on -m64 targets.
(NOTE, this issue does NOT exist on -m32 targets).
