Removed bytecode transformation for sequence packing/unpacking.
It depended on the previously removed basic block checker to
prevent a jump into the middle of the transformed block.
Clears SF 757818: tuple assignment -- SystemError: unknown opcode
diff --git a/Python/compile.c b/Python/compile.c
index 1d01a26..61b3c96 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -363,34 +363,6 @@
SETARG(codestr, i, 4);
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)
- continue;
- 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: