;; Copyright (C) 2004-2017 Free Software Foundation, Inc. ;; ;; This file is part of GCC. ;; ;; GCC is free software; you can redistribute it and/or modify ;; it under the terms of the GNU General Public License as published by ;; the Free Software Foundation; either version 3, or (at your option) ;; any later version. ;; ;; GCC is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public License ;; along with GCC; see the file COPYING3. If not see ;; . ;; ;; DFA-based pipeline description for Broadcom SB-1 ;; ;; The Broadcom SB-1 core is 4-way superscalar, in-order. It has 2 load/store ;; pipes (one of which can support some ALU operations), 2 alu pipes, 2 FP ;; pipes, and 1 MDMX pipes. It can issue 2 ls insns and 2 exe/fpu/mdmx insns ;; each cycle. ;; We model the 4-way issue by ordering unit choices. The possible choices are ;; {ex1,fp1}|{ex0,fp0}|ls1|ls0. Instructions issue to the first eligible unit ;; in the list in most cases. Non-indexed load/stores issue to ls0 first. ;; simple alu operations issue to ls1 if it is still available, and their ;; operands are ready (no co-issue with loads), otherwise to the first ;; available ex unit. ;; When exceptions are enabled, can only issue FP insns to fp1. This is ;; to ensure that instructions complete in order. The -mfp-exceptions option ;; can be used to specify whether the system has FP exceptions enabled or not. ;; In 32-bit mode, dependent FP can't co-issue with load, and only one FP exe ;; insn can issue per cycle (fp1). ;; The A1 MDMX pipe is separate from the FP pipes, but uses the same register ;; file. As a result, once an MDMX insn is issued, no FP insns can be issued ;; for 3 cycles. When an FP insn is issued, no MDMX insn can be issued for ;; 5 cycles. This is currently not handled because there is no MDMX insn ;; support as yet. ;; ;; We use two automata. sb1_cpu_div is for the integer divides, which are ;; not pipelined. sb1_cpu is for everything else. ;; (define_automaton "sb1_cpu, sb1_cpu_div") ;; Load/store function units. (define_cpu_unit "sb1_ls0" "sb1_cpu") (define_cpu_unit "sb1_ls1" "sb1_cpu") ;; CPU function units. (define_cpu_unit "sb1_ex0" "sb1_cpu") (define_cpu_unit "sb1_ex1" "sb1_cpu") ;; The divide unit is not pipelined, and blocks hi/lo reads and writes. (define_cpu_unit "sb1_div" "sb1_cpu_div") ;; DMULT block any multiply from issuing in the next cycle. (define_cpu_unit "sb1_mul" "sb1_cpu") ;; Floating-point units. (define_cpu_unit "sb1_fp0" "sb1_cpu") (define_cpu_unit "sb1_fp1" "sb1_cpu") ;; Can only issue to one of the ex and fp pipes at a time. (exclusion_set "sb1_ex0" "sb1_fp0") (exclusion_set "sb1_ex1" "sb1_fp1") ;; Define an SB-1 specific attribute to simplify some FP descriptions. ;; We can use 2 FP pipes only if we have 64-bit FP code, and exceptions are ;; disabled. (define_attr "sb1_fp_pipes" "one,two" (cond [(and (match_test "TARGET_FLOAT64") (not (match_test "TARGET_FP_EXCEPTIONS"))) (const_string "two")] (const_string "one"))) ;; Define reservations for common combinations. ;; For long cycle operations, the FPU has a 4 cycle pipeline that repeats, ;; effectively re-issuing the operation every 4 cycles. This means that we ;; can have at most 4 long-cycle operations per pipe. ;; ??? The fdiv operations should be e.g. ;; sb1_fp1_4cycles*7" | "sb1_fp0_4cycle*7 ;; but the DFA is too large when we do that. Perhaps have to use scheduler ;; hooks here. ;; ??? Try limiting scheduler to 2 long latency operations, and see if this ;; results in a usable DFA, and whether it helps code performance. ;;(define_reservation "sb1_fp0_4cycles" "sb1_fp0, nothing*3") ;;(define_reservation "sb1_fp1_4cycles" "sb1_fp1, nothing*3") ;; ;; The ordering of the instruction-execution-path/resource-usage ;; descriptions (also known as reservation RTL) is roughly ordered ;; based on the define attribute RTL for the "type" classification. ;; When modifying, remember that the first test that matches is the ;; reservation used! ;; (define_insn_reservation "ir_sb1_unknown" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "unknown,multi,atomic,syncloop")) "sb1_ls0+sb1_ls1+sb1_ex0+sb1_ex1+sb1_fp0+sb1_fp1") ;; predicted taken branch causes 2 cycle ifetch bubble. predicted not ;; taken branch causes 0 cycle ifetch bubble. mispredicted branch causes 8 ;; cycle ifetch bubble. We assume all branches predicted not taken. ;; ??? This assumption that branches are predicated not taken should be ;; investigated. Maybe using 2 here will give better results. (define_insn_reservation "ir_sb1_branch" 0 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "branch,jump,call")) "sb1_ex0") ;; ??? This is 1 cycle for ldl/ldr to ldl/ldr when they use the same data ;; register as destination. ;; ??? SB-1 can co-issue a load with a dependent arith insn if it executes on ;; an EX unit. Can not co-issue if the dependent insn executes on an LS unit. ;; SB-1A can always co-issue here. ;; A load normally has a latency of zero cycles. In some cases, dependent ;; insns can be issued in the same cycle. However, a value of 1 gives ;; better performance in empirical testing. (define_insn_reservation "ir_sb1_load" 1 (and (eq_attr "cpu" "sb1") (eq_attr "type" "load,prefetch")) "sb1_ls0 | sb1_ls1") (define_insn_reservation "ir_sb1a_load" 0 (and (eq_attr "cpu" "sb1a") (eq_attr "type" "load,prefetch")) "sb1_ls0 | sb1_ls1") ;; Can not co-issue fpload with fp exe when in 32-bit mode. (define_insn_reservation "ir_sb1_fpload" 0 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fpload") (match_test "TARGET_FLOAT64"))) "sb1_ls0 | sb1_ls1") (define_insn_reservation "ir_sb1_fpload_32bitfp" 1 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fpload") (not (match_test "TARGET_FLOAT64")))) "sb1_ls0 | sb1_ls1") ;; Indexed loads can only execute on LS1 pipe. (define_insn_reservation "ir_sb1_fpidxload" 0 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fpidxload") (match_test "TARGET_FLOAT64"))) "sb1_ls1") (define_insn_reservation "ir_sb1_fpidxload_32bitfp" 1 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fpidxload") (not (match_test "TARGET_FLOAT64")))) "sb1_ls1") ;; prefx can only execute on the ls1 pipe. (define_insn_reservation "ir_sb1_prefetchx" 0 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "prefetchx")) "sb1_ls1") ;; ??? There is a 4.5 cycle latency if a store is followed by a load, and ;; there is a RAW dependency. (define_insn_reservation "ir_sb1_store" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "store")) "sb1_ls0+sb1_ex1 | sb1_ls0+sb1_ex0 | sb1_ls1+sb1_ex1 | sb1_ls1+sb1_ex0") (define_insn_reservation "ir_sb1_fpstore" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "fpstore")) "sb1_ls0+sb1_fp1 | sb1_ls0+sb1_fp0 | sb1_ls1+sb1_fp1 | sb1_ls1+sb1_fp0") ;; Indexed stores can only execute on LS1 pipe. (define_insn_reservation "ir_sb1_fpidxstore" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "fpidxstore")) "sb1_ls1+sb1_fp1 | sb1_ls1+sb1_fp0") ;; Load latencies are 3 cycles for one load to another load or store (address ;; only). This is 0 cycles for one load to a store using it as the data ;; written. ;; This assumes that if a load is dependent on a previous insn, then it must ;; be an address dependence. (define_bypass 3 "ir_sb1_load,ir_sb1a_load,ir_sb1_fpload,ir_sb1_fpload_32bitfp, ir_sb1_fpidxload,ir_sb1_fpidxload_32bitfp" "ir_sb1_load,ir_sb1a_load,ir_sb1_fpload,ir_sb1_fpload_32bitfp, ir_sb1_fpidxload,ir_sb1_fpidxload_32bitfp,ir_sb1_prefetchx") (define_bypass 3 "ir_sb1_load,ir_sb1a_load,ir_sb1_fpload,ir_sb1_fpload_32bitfp, ir_sb1_fpidxload,ir_sb1_fpidxload_32bitfp" "ir_sb1_store,ir_sb1_fpstore,ir_sb1_fpidxstore" "!mips_store_data_bypass_p") ;; On SB-1, simple alu instructions can execute on the LS1 unit. ;; ??? A simple alu insn issued on an LS unit has 0 cycle latency to an EX ;; insn, to a store (for data), and to an xfer insn. It has 1 cycle latency to ;; another LS insn (excluding store data). A simple alu insn issued on an EX ;; unit has a latency of 5 cycles when the results goes to a LS unit (excluding ;; store data), otherwise a latency of 1 cycle. ;; ??? We cannot handle latencies properly for simple alu instructions ;; within the DFA pipeline model. Latencies can be defined only from one ;; insn reservation to another. We can't make them depend on which function ;; unit was used. This isn't a DFA flaw. There is a conflict here, as we ;; need to know the latency before we can determine which unit will be ;; available, but we need to know which unit it is issued to before we can ;; compute the latency. Perhaps this can be handled via scheduler hooks. ;; This needs to be investigated. ;; ??? Optimal scheduling taking the LS units into account seems to require ;; a pre-scheduling pass. We need to determine which instructions feed results ;; into store/load addresses, and thus benefit most from being issued to the ;; LS unit. Also, we need to prune the list to ensure we don't overschedule ;; insns to the LS unit, and that we don't conflict with insns that need LS1 ;; such as indexed loads. We then need to emit nops to ensure that simple ;; alu instructions that are not supposed to be scheduled to LS1 don't ;; accidentally end up there because LS1 is free when they are issued. This ;; will be a lot of work, and it isn't clear how useful it will be. ;; Empirical testing shows that 2 gives the best result. (define_insn_reservation "ir_sb1_simple_alu" 2 (and (eq_attr "cpu" "sb1") (eq_attr "type" "const,arith,logical,move,signext")) "sb1_ls1 | sb1_ex1 | sb1_ex0") ;; On SB-1A, simple alu instructions can not execute on the LS1 unit, and we ;; have none of the above problems. (define_insn_reservation "ir_sb1a_simple_alu" 1 (and (eq_attr "cpu" "sb1a") (eq_attr "type" "const,arith,logical,move,signext")) "sb1_ex1 | sb1_ex0") ;; ??? condmove also includes some FP instructions that execute on the FP ;; units. This needs to be clarified. (define_insn_reservation "ir_sb1_alu" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "condmove,nop,shift")) "sb1_ex1 | sb1_ex0") ;; These are type arith/darith that only execute on the EX0 unit. (define_insn_reservation "ir_sb1_alu_0" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "slt,clz,trap")) "sb1_ex0") ;; An alu insn issued on an EX unit has a latency of 5 cycles when the ;; result goes to a LS unit (excluding store data). ;; This assumes that if a load is dependent on a previous insn, then it must ;; be an address dependence. (define_bypass 5 "ir_sb1a_simple_alu,ir_sb1_alu,ir_sb1_alu_0,ir_sb1_mfhi,ir_sb1_mflo" "ir_sb1_load,ir_sb1a_load,ir_sb1_fpload,ir_sb1_fpload_32bitfp, ir_sb1_fpidxload,ir_sb1_fpidxload_32bitfp,ir_sb1_prefetchx") (define_bypass 5 "ir_sb1a_simple_alu,ir_sb1_alu,ir_sb1_alu_0,ir_sb1_mfhi,ir_sb1_mflo" "ir_sb1_store,ir_sb1_fpstore,ir_sb1_fpidxstore" "!mips_store_data_bypass_p") ;; mf{hi,lo} is 1 cycle. (define_insn_reservation "ir_sb1_mfhi" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "mfhi")) "sb1_ex1") (define_insn_reservation "ir_sb1_mflo" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "mflo")) "sb1_ex1") ;; mt{hi,lo} to mul/div is 4 cycles. (define_insn_reservation "ir_sb1_mthilo" 4 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "mthi,mtlo")) "sb1_ex1") ;; mt{hi,lo} to mf{hi,lo} is 3 cycles. (define_bypass 3 "ir_sb1_mthilo" "ir_sb1_mfhi,ir_sb1_mflo") ;; multiply latency to an EX operation is 3 cycles. ;; ??? Should check whether we need to make multiply conflict with moves ;; to/from hilo registers. (define_insn_reservation "ir_sb1_mulsi" 3 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "imul,imul3,imadd") (eq_attr "mode" "SI"))) "sb1_ex1+sb1_mul") ;; muldi to mfhi is 4 cycles. ;; Blocks any other multiply insn issue for 1 cycle. (define_insn_reservation "ir_sb1_muldi" 4 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "imul,imul3") (eq_attr "mode" "DI"))) "sb1_ex1+sb1_mul, sb1_mul") ;; muldi to mflo is 3 cycles. (define_bypass 3 "ir_sb1_muldi" "ir_sb1_mflo") ;; mul latency is 7 cycles if the result is used by any LS insn. ;; This assumes that if a load is dependent on a previous insn, then it must ;; be an address dependence. (define_bypass 7 "ir_sb1_mulsi,ir_sb1_muldi" "ir_sb1_load,ir_sb1a_load,ir_sb1_fpload,ir_sb1_fpload_32bitfp, ir_sb1_fpidxload,ir_sb1_fpidxload_32bitfp,ir_sb1_prefetchx") (define_bypass 7 "ir_sb1_mulsi,ir_sb1_muldi" "ir_sb1_store,ir_sb1_fpstore,ir_sb1_fpidxstore" "!mips_store_data_bypass_p") ;; The divide unit is not pipelined. Divide busy is asserted in the 4th ;; cycle, and then deasserted on the latency cycle. So only one divide at ;; a time, but the first/last 4 cycles can overlap. ;; ??? All divides block writes to hi/lo regs. hi/lo regs are written 4 cycles ;; after the latency cycle for divides (e.g. 40/72). dmult writes lo in ;; cycle 7, and hi in cycle 8. All other insns write hi/lo regs in cycle 7. ;; Default for output dependencies is the difference in latencies, which is ;; only 1 cycle off here, e.g. div to mtlo stalls for 32 cycles, but should ;; stall for 33 cycles. This does not seem significant enough to worry about. (define_insn_reservation "ir_sb1_divsi" 36 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "idiv") (eq_attr "mode" "SI"))) "sb1_ex1, nothing*3, sb1_div*32") (define_insn_reservation "ir_sb1_divdi" 68 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "idiv") (eq_attr "mode" "DI"))) "sb1_ex1, nothing*3, sb1_div*64") (define_insn_reservation "ir_sb1_fpu_2pipes" 4 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fmove,fadd,fmul,fabs,fneg,fcvt,frdiv1,frsqrt1") (eq_attr "sb1_fp_pipes" "two"))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_fpu_1pipe" 4 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fmove,fadd,fmul,fabs,fneg,fcvt,frdiv1,frsqrt1") (eq_attr "sb1_fp_pipes" "one"))) "sb1_fp1") (define_insn_reservation "ir_sb1_fpu_step2_2pipes" 8 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frdiv2,frsqrt2") (eq_attr "sb1_fp_pipes" "two"))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_fpu_step2_1pipe" 8 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frdiv2,frsqrt2") (eq_attr "sb1_fp_pipes" "one"))) "sb1_fp1") ;; ??? madd/msub 4-cycle latency to itself (same fr?), but 8 cycle latency ;; otherwise. ;; ??? Blocks issue of another non-madd/msub after 4 cycles. (define_insn_reservation "ir_sb1_fmadd_2pipes" 8 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fmadd") (eq_attr "sb1_fp_pipes" "two"))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_fmadd_1pipe" 8 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fmadd") (eq_attr "sb1_fp_pipes" "one"))) "sb1_fp1") (define_insn_reservation "ir_sb1_fcmp" 4 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "fcmp")) "sb1_fp1") ;; mtc1 latency 5 cycles. (define_insn_reservation "ir_sb1_mtxfer" 5 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "mtc")) "sb1_fp0") ;; mfc1 latency 1 cycle. (define_insn_reservation "ir_sb1_mfxfer" 1 (and (eq_attr "cpu" "sb1,sb1a") (eq_attr "type" "mfc")) "sb1_fp0") ;; ??? Can deliver at most 1 result per every 6 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_divsf_2pipes" 24 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fdiv") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_divsf_1pipe" 24 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fdiv") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1") ;; ??? Can deliver at most 1 result per every 8 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_divdf_2pipes" 32 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fdiv") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_divdf_1pipe" 32 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fdiv") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1") ;; ??? Can deliver at most 1 result per every 3 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_recipsf_2pipes" 12 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frdiv") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_recipsf_1pipe" 12 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frdiv") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1") ;; ??? Can deliver at most 1 result per every 5 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_recipdf_2pipes" 20 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frdiv") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_recipdf_1pipe" 20 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frdiv") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1") ;; ??? Can deliver at most 1 result per every 7 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_sqrtsf_2pipes" 28 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fsqrt") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_sqrtsf_1pipe" 28 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fsqrt") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1") ;; ??? Can deliver at most 1 result per every 10 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_sqrtdf_2pipes" 40 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fsqrt") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_sqrtdf_1pipe" 40 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "fsqrt") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1") ;; ??? Can deliver at most 1 result per every 4 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_rsqrtsf_2pipes" 16 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frsqrt") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_rsqrtsf_1pipe" 16 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frsqrt") (and (eq_attr "mode" "SF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1") ;; ??? Can deliver at most 1 result per every 7 cycles because of issue ;; restrictions. (define_insn_reservation "ir_sb1_rsqrtdf_2pipes" 28 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frsqrt") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "two")))) "sb1_fp1 | sb1_fp0") (define_insn_reservation "ir_sb1_rsqrtdf_1pipe" 28 (and (eq_attr "cpu" "sb1,sb1a") (and (eq_attr "type" "frsqrt") (and (eq_attr "mode" "DF") (eq_attr "sb1_fp_pipes" "one")))) "sb1_fp1")