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[176.184.10.225]) by smtp.gmail.com with ESMTPSA id k25-20020a7bc419000000b003f96d10eafbsm4143467wmi.12.2023.06.19.07.23.40 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jun 2023 07:23:41 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH v3 3/5] tcg: Elide memory barriers implied by the host memory model Date: Mon, 19 Jun 2023 16:23:31 +0200 Message-Id: <20230619142333.429028-4-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230619142333.429028-1-richard.henderson@linaro.org> References: <20230619142333.429028-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::335; envelope-from=richard.henderson@linaro.org; helo=mail-wm1-x335.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Reduce the set of required barriers to those needed by the host right from the beginning. Signed-off-by: Richard Henderson --- tcg/tcg-op.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c index 7aadb37756..574001c221 100644 --- a/tcg/tcg-op.c +++ b/tcg/tcg-op.c @@ -115,7 +115,11 @@ void tcg_gen_mb(TCGBar mb_type) #endif if (parallel) { - tcg_gen_op1(INDEX_op_mb, mb_type); + /* We can elide anything which the host provides for free. */ + mb_type &= ~TCG_TARGET_DEFAULT_MO; + if (mb_type & TCG_MO_ALL) { + tcg_gen_op1(INDEX_op_mb, mb_type); + } } }