Update of /cvsroot/python/python/dist/src/Python In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv2403 Modified Files: compile.c Log Message: Teach the peepholer to fold unary operations on constants. Afterwards, -0.5 loads in a single step and no longer requires a runtime UNARY_NEGATIVE operation. Index: compile.c =================================================================== RCS file: /cvsroot/python/python/dist/src/Python/compile.c,v retrieving revision 2.344 retrieving revision 2.345 diff -u -d -r2.344 -r2.345 --- compile.c 10 Feb 2005 01:42:32 -0000 2.344 +++ compile.c 20 Feb 2005 12:41:32 -0000 2.345 @@ -542,6 +542,54 @@ return 1; } +static int +fold_unaryops_on_constants(unsigned char *codestr, PyObject *consts) +{ + PyObject *newconst, *v; + int len_consts, opcode; + + /* Pre-conditions */ + assert(PyList_CheckExact(consts)); + assert(codestr[0] == LOAD_CONST); + + /* Create new constant */ + v = PyList_GET_ITEM(consts, GETARG(codestr, 0)); + opcode = codestr[3]; + switch (opcode) { + case UNARY_NEGATIVE: + newconst = PyNumber_Negative(v); + break; + case UNARY_CONVERT: + newconst = PyObject_Repr(v); + break; + case UNARY_INVERT: + newconst = PyNumber_Invert(v); + break; + default: + /* Called with an unknown opcode */ + assert(0); + return 0; + } + if (newconst == NULL) { + PyErr_Clear(); + return 0; + } + + /* Append folded constant into consts table */ + len_consts = PyList_GET_SIZE(consts); + if (PyList_Append(consts, newconst)) { + Py_DECREF(newconst); + return 0; + } + Py_DECREF(newconst); + + /* Write NOP LOAD_CONST newconst */ + codestr[0] = NOP; + codestr[1] = LOAD_CONST; + SETARG(codestr, 1, len_consts); + return 1; +} + static unsigned int * markblocks(unsigned char *code, int len) { @@ -771,6 +819,20 @@ } break; + /* Fold unary ops on constants. + LOAD_CONST c1 UNARY_OP --> LOAD_CONST unary_op(c) */ + case UNARY_NEGATIVE: + case UNARY_CONVERT: + case UNARY_INVERT: + if (lastlc >= 1 && + ISBASICBLOCK(blocks, i-3, 4) && + fold_unaryops_on_constants(&codestr[i-3], consts)) { + i -= 2; + assert(codestr[i] == LOAD_CONST); + cumlc = 1; + } + break; + /* Simplify conditional jump to conditional jump where the result of the first test implies the success of a similar test or the failure of the opposite test.