From: Xi Ruoyao <xry111@xry111.site>
To: gcc-patches@gcc.gnu.org
Cc: chenglulu <chenglulu@loongson.cn>,
i@xen0n.name, xuchenghua@loongson.cn,
Xi Ruoyao <xry111@xry111.site>
Subject: [PATCH 4/5] LoongArch: Don't emit dbar 0x700 if -mld-seq-sa
Date: Thu, 16 Nov 2023 21:18:36 +0800 [thread overview]
Message-ID: <20231116131836.504699-6-xry111@xry111.site> (raw)
In-Reply-To: <20231116131836.504699-2-xry111@xry111.site>
This option (CPUCFG word 0x3 bit 23) means "the hardware guarantee that
two loads on the same address won't be reordered with each other". Thus
we can omit the "load-load" barrier dbar 0x700.
This is only a micro-optimization because dbar 0x700 is already treated
as nop if the hardware supports LD_SEQ_SA.
gcc/ChangeLog:
* config/loongarch/loongarch.cc (loongarch_print_operand): Don't
print dbar 0x700 if TARGET_LD_SEQ_SA.
---
gcc/config/loongarch/loongarch.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 6f89d468795..c6eec2345a9 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -6061,7 +6061,7 @@ loongarch_print_operand (FILE *file, rtx op, int letter)
if (loongarch_cas_failure_memorder_needs_acquire (
memmodel_from_int (INTVAL (op))))
fputs ("dbar\t0b10100", file);
- else
+ else if (!TARGET_LD_SEQ_SA)
fputs ("dbar\t0x700", file);
break;
--
2.42.1
next prev parent reply other threads:[~2023-11-16 13:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-16 13:18 [PATCH 0/5] LoongArch: Initial LA664 support Xi Ruoyao
2023-11-16 13:18 ` [PATCH 1/5] LoongArch: Switch loongarch-def to C++ Xi Ruoyao
2023-11-16 13:18 ` [PATCH 2/5] LoongArch: genopts: Add infrastructure to generate code for new features in ISA evolution Xi Ruoyao
2023-11-16 13:18 ` [PATCH 3/5] LoongArch: Take the advantage of -mdiv32 if it's enabled Xi Ruoyao
2023-11-16 13:18 ` Xi Ruoyao [this message]
2023-11-16 13:18 ` [PATCH 5/5] LoongArch: Add -march=la664 and -mtune=la664 Xi Ruoyao
2023-11-17 2:41 ` [PATCH 0/5] LoongArch: Initial LA664 support chenglulu
2023-11-17 4:55 ` Xi Ruoyao
2023-11-17 6:07 ` chenglulu
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