jump optimizations
This unifies VT_CMP with VT_JMP(i) by using mostly VT_CMP
with both a positive and a negative jump target list.
Such we can delay putting the non-inverted or inverted jump
until we can see which one is nore suitable (in most cases).
example:
if (a && b || c && d)
e = 0;
before this patch:
a: 8b 45 fc mov 0xfffffffc(%ebp),%eax
d: 83 f8 00 cmp $0x0,%eax
10: 0f 84 11 00 00 00 je 27 <main+0x27>
16: 8b 45 f8 mov 0xfffffff8(%ebp),%eax
19: 83 f8 00 cmp $0x0,%eax
1c: 0f 84 05 00 00 00 je 27 <main+0x27>
22: e9 22 00 00 00 jmp 49 <main+0x49>
27: 8b 45 f4 mov 0xfffffff4(%ebp),%eax
2a: 83 f8 00 cmp $0x0,%eax
2d: 0f 84 11 00 00 00 je 44 <main+0x44>
33: 8b 45 f0 mov 0xfffffff0(%ebp),%eax
36: 83 f8 00 cmp $0x0,%eax
39: 0f 84 05 00 00 00 je 44 <main+0x44>
3f: e9 05 00 00 00 jmp 49 <main+0x49>
44: e9 08 00 00 00 jmp 51 <main+0x51>
49: b8 00 00 00 00 mov $0x0,%eax
4e: 89 45 ec mov %eax,0xffffffec(%ebp)
51: ...
with this patch:
a: 8b 45 fc mov 0xfffffffc(%ebp),%eax
d: 83 f8 00 cmp $0x0,%eax
10: 0f 84 0c 00 00 00 je 22 <main+0x22>
16: 8b 45 f8 mov 0xfffffff8(%ebp),%eax
19: 83 f8 00 cmp $0x0,%eax
1c: 0f 85 18 00 00 00 jne 3a <main+0x3a>
22: 8b 45 f4 mov 0xfffffff4(%ebp),%eax
25: 83 f8 00 cmp $0x0,%eax
28: 0f 84 14 00 00 00 je 42 <main+0x42>
2e: 8b 45 f0 mov 0xfffffff0(%ebp),%eax
31: 83 f8 00 cmp $0x0,%eax
34: 0f 84 08 00 00 00 je 42 <main+0x42>
3a: b8 00 00 00 00 mov $0x0,%eax
3f: 89 45 ec mov %eax,0xffffffec(%ebp)
42: ...
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