| author | Tom Tromey <tom@tromey.com> | 2018年02月27日 18:26:43 -0700 |
|---|---|---|
| committer | Tom Tromey <tom@tromey.com> | 2020年01月07日 16:27:55 -0700 |
| commit | 06149d7834c8b7e8788c51a6d03edd9eaeeca58e (patch) | |
| tree | 7ffad5d6597e13845a87509a8006730d7592cec7 | |
| parent | d2aa30874cdc94cb1fb31e305173a4140efa82c7 (diff) | |
| download | libjit-06149d7834c8b7e8788c51a6d03edd9eaeeca58e.tar.gz | |
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | jit/jit-block.c | 103 |
@@ -1,3 +1,8 @@ +2019年12月27日 Tom Tromey <tom@tromey.com> + + * jit/jit-block.c (_jit_invert_condition): New function. + (_jit_block_clean_cfg): Optimize branch-around-branch. + 2020年01月06日 Tom Tromey <tom@tromey.com> * tests/unit/Makefile.am: New file. diff --git a/jit/jit-block.c b/jit/jit-block.c index 6ffd329..7e1eeea 100644 --- a/jit/jit-block.c +++ b/jit/jit-block.c @@ -21,6 +21,7 @@ */ #include "jit-internal.h" +#include <stdlib.h> /*@ @@ -762,6 +763,66 @@ _jit_block_build_cfg(jit_function_t func) build_edges(func, 1); } +static int +_jit_invert_condition (int opcode) +{ + switch(opcode) + { + case JIT_OP_BR_IEQ: opcode = JIT_OP_BR_INE; break; + case JIT_OP_BR_INE: opcode = JIT_OP_BR_IEQ; break; + case JIT_OP_BR_ILT: opcode = JIT_OP_BR_IGE; break; + case JIT_OP_BR_ILT_UN: opcode = JIT_OP_BR_IGE_UN; break; + case JIT_OP_BR_ILE: opcode = JIT_OP_BR_IGT; break; + case JIT_OP_BR_ILE_UN: opcode = JIT_OP_BR_IGT_UN; break; + case JIT_OP_BR_IGT: opcode = JIT_OP_BR_ILE; break; + case JIT_OP_BR_IGT_UN: opcode = JIT_OP_BR_ILE_UN; break; + case JIT_OP_BR_IGE: opcode = JIT_OP_BR_ILT; break; + case JIT_OP_BR_IGE_UN: opcode = JIT_OP_BR_ILT_UN; break; + case JIT_OP_BR_LEQ: opcode = JIT_OP_BR_LNE; break; + case JIT_OP_BR_LNE: opcode = JIT_OP_BR_LEQ; break; + case JIT_OP_BR_LLT: opcode = JIT_OP_BR_LGE; break; + case JIT_OP_BR_LLT_UN: opcode = JIT_OP_BR_LGE_UN; break; + case JIT_OP_BR_LLE: opcode = JIT_OP_BR_LGT; break; + case JIT_OP_BR_LLE_UN: opcode = JIT_OP_BR_LGT_UN; break; + case JIT_OP_BR_LGT: opcode = JIT_OP_BR_LLE; break; + case JIT_OP_BR_LGT_UN: opcode = JIT_OP_BR_LLE_UN; break; + case JIT_OP_BR_LGE: opcode = JIT_OP_BR_LLT; break; + case JIT_OP_BR_LGE_UN: opcode = JIT_OP_BR_LLT_UN; break; + case JIT_OP_BR_FEQ: opcode = JIT_OP_BR_FNE; break; + case JIT_OP_BR_FNE: opcode = JIT_OP_BR_FEQ; break; + case JIT_OP_BR_FLT: opcode = JIT_OP_BR_FGE_INV; break; + case JIT_OP_BR_FLE: opcode = JIT_OP_BR_FGT_INV; break; + case JIT_OP_BR_FGT: opcode = JIT_OP_BR_FLE_INV; break; + case JIT_OP_BR_FGE: opcode = JIT_OP_BR_FLT_INV; break; + case JIT_OP_BR_FLT_INV: opcode = JIT_OP_BR_FGE; break; + case JIT_OP_BR_FLE_INV: opcode = JIT_OP_BR_FGT; break; + case JIT_OP_BR_FGT_INV: opcode = JIT_OP_BR_FLE; break; + case JIT_OP_BR_FGE_INV: opcode = JIT_OP_BR_FLT; break; + case JIT_OP_BR_DEQ: opcode = JIT_OP_BR_DNE; break; + case JIT_OP_BR_DNE: opcode = JIT_OP_BR_DEQ; break; + case JIT_OP_BR_DLT: opcode = JIT_OP_BR_DGE_INV; break; + case JIT_OP_BR_DLE: opcode = JIT_OP_BR_DGT_INV; break; + case JIT_OP_BR_DGT: opcode = JIT_OP_BR_DLE_INV; break; + case JIT_OP_BR_DGE: opcode = JIT_OP_BR_DLT_INV; break; + case JIT_OP_BR_DLT_INV: opcode = JIT_OP_BR_DGE; break; + case JIT_OP_BR_DLE_INV: opcode = JIT_OP_BR_DGT; break; + case JIT_OP_BR_DGT_INV: opcode = JIT_OP_BR_DLE; break; + case JIT_OP_BR_DGE_INV: opcode = JIT_OP_BR_DLT; break; + case JIT_OP_BR_NFEQ: opcode = JIT_OP_BR_NFNE; break; + case JIT_OP_BR_NFNE: opcode = JIT_OP_BR_NFEQ; break; + case JIT_OP_BR_NFLT: opcode = JIT_OP_BR_NFGE_INV; break; + case JIT_OP_BR_NFLE: opcode = JIT_OP_BR_NFGT_INV; break; + case JIT_OP_BR_NFGT: opcode = JIT_OP_BR_NFLE_INV; break; + case JIT_OP_BR_NFGE: opcode = JIT_OP_BR_NFLT_INV; break; + case JIT_OP_BR_NFLT_INV: opcode = JIT_OP_BR_NFGE; break; + case JIT_OP_BR_NFLE_INV: opcode = JIT_OP_BR_NFGT; break; + case JIT_OP_BR_NFGT_INV: opcode = JIT_OP_BR_NFLE; break; + case JIT_OP_BR_NFGE_INV: opcode = JIT_OP_BR_NFLT; break; + default: abort(); + } + return opcode; +} + void _jit_block_clean_cfg(jit_function_t func) { @@ -855,6 +916,48 @@ _jit_block_clean_cfg(jit_function_t func) block->ends_in_dead = 1; delete_edge(func, block->succs[1]); } + else if(block->num_succs == 2 + && is_empty_block(block->next) + && block->next->num_succs == 1 + /* This transformation is not safe if + the block we're rewriting has other + predecessors, or has had its + address taken. */ + && block->next->num_preds == 1 + && block->next->address_of == 0 + && block->next->succs[0]->flags == _JIT_EDGE_BRANCH + && block->succs[0]->dst == block->next->next) + { + /* We have a conditional branch, that + branches around the next block, and + the next block consists of just a + jump, like: + + if l7 != 3 then goto .L0 + goto .L1 + .L0: + + In this case we can invert the + condition and retarget the jump, + resulting in: + + if l7 == 3 then goto .L1 + nop + .L0: + */ + insn->opcode = _jit_invert_condition(insn->opcode); + detach_edge_dst(block->succs[0]); + attach_edge_dst(block->succs[0], block->next->succs[0]->dst); + insn->dest = (jit_value_t) block->next->succs[0]->dst->label; + detach_edge_dst(block->next->succs[0]); + attach_edge_dst(block->next->succs[0], block->next->next); + block->next->succs[0]->flags = _JIT_EDGE_FALLTHRU; + /* Rewrite the last instruction of the + unnecessary block to be a NOP. */ + block->next->insns[block->next->num_insns - 1].opcode = JIT_OP_NOP; + block->next->ends_in_dead = 0; + changed = 1; + } } /* Try to simplify basic blocks that end with fallthrough or |