[Python-Dev] LOAD_CONST POP_TOP (original) (raw)

Georg Brandl g.brandl at gmx.net
Fri Jun 30 20:39:13 CEST 2006

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Hi,

the following patch tries to fix the LOAD_CONST POP_TOP optimization lost in 2.5 (bug #1333982).

An example for this is:

def f(): 'a' # docstring 'b'

Georg

PS: Hmm. While looking, I see that 2.4 doesn't optimize away other constants like

def g(): 1

Index: Python/compile.c

--- Python/compile.c (Revision 47150) +++ Python/compile.c (Arbeitskopie) @@ -775,10 +775,16 @@ } break;

•                   case LOAD_CONST:

•                           cumlc = lastlc + 1;

•                           /* Skip over LOAD_CONST POP_TOP */

•                           if (codestr[i+3] == POP_TOP) {

•                                   memset(codestr+i, NOP, 4);

•                                   cumlc = 0;

•                                   break;

•                           }
                             /* Skip over LOAD_CONST trueconst
                                 JUMP_IF_FALSE xx  POP_TOP */

•                   case LOAD_CONST:

•                           cumlc = lastlc + 1;
                             j = GETARG(codestr, i);
                             if (codestr[i+3] != JUMP_IF_FALSE  ||
                                 codestr[i+6] != POP_TOP  ||

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