[Python-checkins] python/dist/src/Python ceval.c, 2.400, 2.401 compile.c, 2.303, 2.304

[rhettinger at users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Python
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv26471/Python

Modified Files:
	ceval.c compile.c 
Log Message:
Install two code generation optimizations that depend on NOP.
Reduces the cost of "not" to almost zero.



Index: ceval.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/ceval.c,v
retrieving revision 2.400
retrieving revision 2.401
diff -C2 -d -r2.400 -r2.401
*** ceval.c	17 Jun 2004 10:22:40 -0000	2.400
--- ceval.c	21 Jun 2004 16:31:14 -0000	2.401
***************
*** 850,853 ****
--- 850,856 ----
  		/* case STOP_CODE: this is an error! */
  
+ 		case NOP:
+ 			goto fast_next_opcode;
+ 
  		case LOAD_FAST:
  			x = GETLOCAL(oparg);

Index: compile.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/compile.c,v
retrieving revision 2.303
retrieving revision 2.304
diff -C2 -d -r2.303 -r2.304
*** compile.c	8 Jun 2004 18:52:54 -0000	2.303
--- compile.c	21 Jun 2004 16:31:15 -0000	2.304
***************
*** 393,396 ****
--- 393,423 ----
  		switch (opcode) {
  
+ 		/* Replace UNARY_NOT JUMP_IF_FALSE with NOP JUMP_IF_TRUE */
+ 		case UNARY_NOT:
+ 			if (codestr[i+1] != JUMP_IF_FALSE  ||
+ 			    codestr[i+4] != POP_TOP  ||
+ 			    !ISBASICBLOCK(blocks,i,5))
+ 				continue;
+ 			tgt = GETJUMPTGT(codestr, (i+1));
+ 			if (codestr[tgt] != POP_TOP)
+ 				continue;
+ 			codestr[i] = NOP;
+ 			codestr[i+1] = JUMP_IF_TRUE;
+ 			break;
+ 
+ 		/* not a is b -->  a is not b
+ 		   not a in b -->  a not in b
+ 		   not a is not b -->  a is b
+ 		   not a not in b -->  a in b */
+ 		case COMPARE_OP:
+ 			j = GETARG(codestr, i);
+ 			if (j < 6  ||  j > 9  ||
+ 			    codestr[i+3] != UNARY_NOT  || 
+ 			    !ISBASICBLOCK(blocks,i,4))
+   			 continue;
+ 			SETARG(codestr, i, (j^1));
+ 			codestr[i+3] = NOP;
+ 			break;
+ 
  		/* Skip over LOAD_CONST trueconst  JUMP_IF_FALSE xx  POP_TOP. 
  		   Note, only the first opcode is changed, the others still
***************
*** 419,424 ****
  				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;
  			} 
--- 446,451 ----
  				codestr[i+1] = JUMP_FORWARD;
  				SETARG(codestr, i+1, 2);
! 				codestr[i+4] = NOP;
! 				codestr[i+5] = NOP;
  				continue;
  			} 
***************
*** 429,433 ****
  				codestr[i+2] = JUMP_FORWARD;
  				SETARG(codestr, i+2, 1);
! 				codestr[i+5] = DUP_TOP;
  			}
  			break;
--- 456,460 ----
  				codestr[i+2] = JUMP_FORWARD;
  				SETARG(codestr, i+2, 1);
! 				codestr[i+5] = NOP;
  			}
  			break;