From: Xi Ruoyao <xry111@xry111.site>
To: Lulu Cheng <chenglulu@loongson.cn>, gcc-patches@gcc.gnu.org
Cc: WANG Xuerui <i@xen0n.name>, Chenghua Xu <xuchenghua@loongson.cn>
Subject: Re: [GCC14 PATCH] LoongArch: Optimize additions with immediates
Date: Tue, 04 Apr 2023 16:00:45 +0800 [thread overview]
Message-ID: <62922ce154f7f52147341b905d3c844cd50e6682.camel@xry111.site> (raw)
In-Reply-To: <39b42972-9a0f-3ada-b9b9-2c53da946217@loongson.cn>
On Tue, 2023-04-04 at 11:01 +0800, Lulu Cheng wrote:
/* snip */
> > +unsigned long f10 (unsigned long x) { return x - 0x80000000l * 2; }
> > +unsigned long f11 (unsigned long x) { return x - 0x80000000l * 2; }
> These two test cases are duplicates.
/* snip */
>
> > +unsigned int g10 (unsigned int x) { return x - 0x80000000l * 2; }
> > +unsigned int g11 (unsigned int x) { return x - 0x80000000l * 2; }
> Ditto.
I'll fix them in V2.
> I found that adding this log test case gcc.target/loongarch/stack-check-cfa-1.c and gcc.target/loongarch/stack-check-cfa-2.c test failed.
> Although the test fails, the generated assembly code is better, and there is no problem with the logic of the assembly code. I haven't checked the reason for this yet.
Looks like the change hides PR109035 (like -fpie) for some reason. (But
I still don't understand the root cause of PR109035 anyway.)
f_test:
.LFB0 = .
.cfi_startproc
lu12i.w $r14,65536>>12 # 0x10000
sub.d $r3,$r3,$r14
st.d $r0,$r3,0
sub.d $r3,$r3,$r14
st.d $r0,$r3,0
.cfi_def_cfa_offset 131072
lu12i.w $r13,131072>>12 #
0x20000
or $r12,$r3,$r0
ldx.b $r4,$r12,$r4
add.d $r3,$r3,$r13
.cfi_def_cfa_offset 0
jr $r1
.cfi_endproc
Technically there should be "addu16i.d $r3,$r3,-1" in the prologue and
"addu16i.d $r3,$r3,2" in the epilogue, so we can avoid using r14/r13.
I'll try modifying loongarch_expand_{pro,epi}logue for this.
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
next prev parent reply other threads:[~2023-04-04 8:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-02 14:00 Xi Ruoyao
2023-04-04 3:01 ` Lulu Cheng
2023-04-04 8:00 ` Xi Ruoyao [this message]
2023-04-04 8:40 ` Xi Ruoyao
2023-04-04 9:15 ` Lulu Cheng
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