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([71.212.149.95]) by smtp.gmail.com with ESMTPSA id k8-20020aa79728000000b006875df4773fsm359576pfg.163.2023.10.31.21.11.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 Oct 2023 21:11:48 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: mark.cave-ayland@ilande.co.uk Subject: [PATCH v2 18/21] target/sparc: Discard cpu_cond at the end of each insn Date: Tue, 31 Oct 2023 21:11:29 -0700 Message-Id: <20231101041132.174501-19-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231101041132.174501-1-richard.henderson@linaro.org> References: <20231101041132.174501-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::330; envelope-from=richard.henderson@linaro.org; helo=mail-ot1-x330.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 If the insn raises no exceptions, there will be no path in which cpu_cond is used, and so the computation may be optimized away. Signed-off-by: Richard Henderson --- target/sparc/translate.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/target/sparc/translate.c b/target/sparc/translate.c index 5c9a3d45fa..3564c6032e 100644 --- a/target/sparc/translate.c +++ b/target/sparc/translate.c @@ -171,6 +171,7 @@ typedef struct DisasContext { target_ulong jump_pc[2]; int mem_idx; + bool cpu_cond_live; bool fpu_enabled; bool address_mask_32bit; #ifndef CONFIG_USER_ONLY @@ -912,6 +913,19 @@ static void gen_op_eval_fbo(TCGv dst, TCGv src, unsigned int fcc_offset) tcg_gen_xori_tl(dst, dst, 0x1); } +static void finishing_insn(DisasContext *dc) +{ + /* + * From here, there is no future path through an unwinding exception. + * If the current insn cannot raise an exception, the computation of + * cpu_cond may be able to be elided. + */ + if (dc->cpu_cond_live) { + tcg_gen_discard_tl(cpu_cond); + dc->cpu_cond_live = false; + } +} + static void gen_generic_branch(DisasContext *dc) { TCGv npc0 = tcg_constant_tl(dc->jump_pc[0]); @@ -958,6 +972,7 @@ static void save_state(DisasContext *dc) static void gen_exception(DisasContext *dc, int which) { + finishing_insn(dc); save_state(dc); gen_helper_raise_exception(tcg_env, tcg_constant_i32(which)); dc->base.is_jmp = DISAS_NORETURN; @@ -999,6 +1014,8 @@ static void gen_check_align(DisasContext *dc, TCGv addr, int mask) static void gen_mov_pc_npc(DisasContext *dc) { + finishing_insn(dc); + if (dc->npc & 3) { switch (dc->npc) { case JUMP_PC: @@ -2339,6 +2356,8 @@ static bool advance_pc(DisasContext *dc) { TCGLabel *l1; + finishing_insn(dc); + if (dc->npc & 3) { switch (dc->npc) { case DYNAMIC_PC: @@ -2383,6 +2402,8 @@ static bool advance_jump_cond(DisasContext *dc, DisasCompare *cmp, target_ulong dest = address_mask_i(dc, dc->pc + disp * 4); target_ulong npc; + finishing_insn(dc); + if (cmp->cond == TCG_COND_ALWAYS) { if (annul) { dc->pc = dest; @@ -2449,6 +2470,7 @@ static bool advance_jump_cond(DisasContext *dc, DisasCompare *cmp, } else { tcg_gen_setcondi_tl(cmp->cond, cpu_cond, cmp->c1, cmp->c2); } + dc->cpu_cond_live = true; } } return true; @@ -2585,6 +2607,8 @@ static bool do_tcc(DisasContext *dc, int cond, int cc, tcg_gen_addi_i32(trap, trap, TT_TRAP); } + finishing_insn(dc); + /* Trap always. */ if (cond == 8) { save_state(dc); @@ -3201,6 +3225,7 @@ TRANS(WRSTICK_CMPR, 64, do_wr_special, a, supervisor(dc), do_wrstick_cmpr) static void do_wrpowerdown(DisasContext *dc, TCGv src) { + finishing_insn(dc); save_state(dc); gen_helper_power_down(tcg_env); } @@ -5080,6 +5105,8 @@ static void sparc_tr_tb_stop(DisasContextBase *dcbase, CPUState *cs) DisasDelayException *e, *e_next; bool may_lookup; + finishing_insn(dc); + switch (dc->base.is_jmp) { case DISAS_NEXT: case DISAS_TOO_MANY: