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Extend SF patch #707257: Improve code generation 

to cover the case for:  "x,y,z=1,2,3".  Gives a 30% speed-up.

Also, added FOR_ITER to the list of opcodes that can jump.
This commit is contained in:
Raymond Hettinger 2003-04-15 10:35:07 +00:00
parent 8b7a9a38c6
commit 255a3d08a1
1 changed files with 20 additions and 8 deletions
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28
Python/compile.c
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@ -364,23 +364,35 @@ optimize_code(PyObject *code, PyObject* consts)
break;
/* Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2 JMP+2.
Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2 JMP+1.
Note, these opcodes occur together only in assignment
statements. Accordingly, the unpack opcode is never
a jump target. */
case BUILD_TUPLE:
case BUILD_LIST:
if (codestr[i+3] != UNPACK_SEQUENCE ||
GETARG(codestr, i) != 2 ||
GETARG(codestr, i+3) != 2)
if (codestr[i+3] != UNPACK_SEQUENCE)
continue;
codestr[i] = ROT_TWO;
codestr[i+1] = JUMP_FORWARD;
SETARG(codestr, i+1, 2);
codestr[i+4] = DUP_TOP; /* Filler codes used as NOPs */
codestr[i+5] = POP_TOP;
if (GETARG(codestr, i) == 2 && \
GETARG(codestr, i+3) == 2) {
codestr[i] = ROT_TWO;
codestr[i+1] = JUMP_FORWARD;
SETARG(codestr, i+1, 2);
codestr[i+4] = DUP_TOP; /* Filler codes used as NOPs */
codestr[i+5] = POP_TOP;
continue;
}
if (GETARG(codestr, i) == 3 && \
GETARG(codestr, i+3) == 3) {
codestr[i] = ROT_THREE;
codestr[i+1] = ROT_TWO;
codestr[i+2] = JUMP_FORWARD;
SETARG(codestr, i+2, 1);
codestr[i+5] = DUP_TOP;
}
break;
/* Replace jumps to unconditional jumps */
case FOR_ITER:
case JUMP_FORWARD:
case JUMP_IF_FALSE:
case JUMP_IF_TRUE: