1 // SPDX-License-Identifier: MIT 2 // 3 // optimize.c - main optimization loop 4 // 5 // Copyright (C) 2004 Linus Torvalds 6 // Copyright (C) 2004 Christopher Li 7 8 #include <assert.h> 9 #include "optimize.h" 10 #include "flowgraph.h" 11 #include "linearize.h" 12 #include "liveness.h" 13 #include "flow.h" 14 #include "cse.h" 15 #include "ir.h" 16 #include "ssa.h" 17 18 int repeat_phase; 19 clear_symbol_pseudos(struct entrypoint * ep)20static void clear_symbol_pseudos(struct entrypoint *ep) 21 { 22 pseudo_t pseudo; 23 24 FOR_EACH_PTR(ep->accesses, pseudo) { 25 pseudo->sym->pseudo = NULL; 26 } END_FOR_EACH_PTR(pseudo); 27 } 28 29 clean_up_insns(struct entrypoint * ep)30static void clean_up_insns(struct entrypoint *ep) 31 { 32 struct basic_block *bb; 33 34 FOR_EACH_PTR(ep->bbs, bb) { 35 struct instruction *insn; 36 FOR_EACH_PTR(bb->insns, insn) { 37 repeat_phase |= simplify_instruction(insn); 38 if (!insn->bb) 39 continue; 40 assert(insn->bb == bb); 41 cse_collect(insn); 42 } END_FOR_EACH_PTR(insn); 43 } END_FOR_EACH_PTR(bb); 44 } 45 optimize(struct entrypoint * ep)46void optimize(struct entrypoint *ep) 47 { 48 if (fdump_ir & PASS_LINEARIZE) 49 show_entry(ep); 50 51 /* 52 * Do trivial flow simplification - branches to 53 * branches, kill dead basicblocks etc 54 */ 55 kill_unreachable_bbs(ep); 56 ir_validate(ep); 57 58 domtree_build(ep); 59 60 /* 61 * Turn symbols into pseudos 62 */ 63 if (fpasses & PASS_MEM2REG) 64 ssa_convert(ep); 65 ir_validate(ep); 66 if (fdump_ir & PASS_MEM2REG) 67 show_entry(ep); 68 69 if (!(fpasses & PASS_OPTIM)) 70 return; 71 repeat: 72 /* 73 * Remove trivial instructions, and try to CSE 74 * the rest. 75 */ 76 do { 77 simplify_memops(ep); 78 //ir_validate(ep); 79 do { 80 repeat_phase = 0; 81 clean_up_insns(ep); 82 if (repeat_phase & REPEAT_CFG_CLEANUP) 83 kill_unreachable_bbs(ep); 84 85 cse_eliminate(ep); 86 87 if (repeat_phase & REPEAT_SYMBOL_CLEANUP) 88 simplify_memops(ep); 89 //ir_validate(ep); 90 } while (repeat_phase); 91 pack_basic_blocks(ep); 92 //ir_validate(ep); 93 if (repeat_phase & REPEAT_CFG_CLEANUP) 94 kill_unreachable_bbs(ep); 95 //ir_validate(ep); 96 } while (repeat_phase); 97 //ir_validate(ep); 98 99 vrfy_flow(ep); 100 101 /* Cleanup */ 102 clear_symbol_pseudos(ep); 103 104 /* And track pseudo register usage */ 105 track_pseudo_liveness(ep); 106 107 /* 108 * Some flow optimizations can only effectively 109 * be done when we've done liveness analysis. But 110 * if they trigger, we need to start all over 111 * again 112 */ 113 if (simplify_flow(ep)) { 114 //ir_validate(ep); 115 clear_liveness(ep); 116 if (repeat_phase & REPEAT_CFG_CLEANUP) 117 kill_unreachable_bbs(ep); 118 goto repeat; 119 } 120 //ir_validate(ep); 121 122 /* Finally, add deathnotes to pseudos now that we have them */ 123 if (dbg_dead) 124 track_pseudo_death(ep); 125 } 126