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Tue, 08 Mar 2022 03:07:37 -0800 (PST) MIME-Version: 1.0 References: <20220308072005.307955-1-richard.henderson@linaro.org> <20220308072005.307955-23-richard.henderson@linaro.org> In-Reply-To: <20220308072005.307955-23-richard.henderson@linaro.org> From: Peter Maydell Date: Tue, 8 Mar 2022 11:07:26 +0000 Message-ID: Subject: Re: [PATCH v4 22/33] target/nios2: Introduce dest_gpr To: Richard Henderson Content-Type: text/plain; charset="UTF-8" X-Host-Lookup-Failed: Reverse DNS lookup failed for 2607:f8b0:4864:20::b2d (failed) Received-SPF: pass client-ip=2607:f8b0:4864:20::b2d; envelope-from=peter.maydell@linaro.org; helo=mail-yb1-xb2d.google.com X-Spam_score_int: -6 X-Spam_score: -0.7 X-Spam_bar: / X-Spam_report: (-0.7 / 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, PDS_HP_HELO_NORDNS=0.659, RCVD_IN_DNSWL_NONE=-0.0001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no 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: , Cc: marex@denx.de, amir.gonnen@neuroblade.ai, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, 8 Mar 2022 at 07:20, Richard Henderson wrote: > > Constrain all references to cpu_R[] to load_gpr and dest_gpr. > This will be required for supporting shadow register sets. > > Signed-off-by: Richard Henderson > --- > target/nios2/translate.c | 144 +++++++++++++++------------------------ > 1 file changed, 55 insertions(+), 89 deletions(-) > @@ -449,15 +435,11 @@ static void rdctl(DisasContext *dc, uint32_t code, uint32_t flags) > g_assert_not_reached(); > #else > R_TYPE(instr, code); > - TCGv t1, t2; > - > - if (unlikely(instr.c == R_ZERO)) { > - return; > - } > + TCGv t1, t2, dest = dest_gpr(dc, instr.c); > > /* Reserved registers read as zero. */ > if (nios2_cr_reserved(&dc->cr_state[instr.imm5])) { > - tcg_gen_movi_tl(cpu_R[instr.c], 0); > + tcg_gen_movi_tl(dest, 0); > return; > } I assume the TCG dead-code elimination will mostly throw away the write-to-R_ZERO stuff, but here for rdctl I suspect it won't. But probably real code doesn't do that kind of silly thing. Reviewed-by: Peter Maydell thanks -- PMM