Commit | Line | Data |
---|---|---|
0b52fb07 | 1 | #ifndef lint |
e804469b | 2 | static char sccsid[] = "@(#)3.then.c 4.1 (Berkeley) 2/11/83"; |
0b52fb07 RH |
3 | #endif not lint |
4 | ||
5 | #include <stdio.h> | |
6 | #include "def.h" | |
7 | #include "3.def.h" | |
8 | ||
9 | #define BRANCHTYPE(t) (t == STOPVX || t == RETVX || t == BRKVX || t == NXTVX || t == GOVX) | |
10 | #define MAXCHUNK 20 | |
11 | /* if else clause smaller than MAXCHUNK and smaller than then clause, | |
12 | and there is no reason not to negate the if, negate the if */ | |
13 | ||
14 | getthen(v) /* turn IFVX into THEN when appropriate, create else ifs where possible */ | |
15 | VERT v; | |
16 | { | |
17 | VERT tch, fch; | |
18 | int tn,fn; | |
19 | int recvar; | |
20 | ||
21 | if (NTYPE(v) == IFVX) | |
22 | { | |
23 | tch = LCHILD(v,THEN); | |
24 | fch = LCHILD(v,ELSE); | |
25 | if (!DEFINED(fch)) | |
26 | mkthen(v); | |
27 | else if (!DEFINED(tch)) | |
28 | { | |
29 | negate(v); | |
30 | mkthen(v); | |
31 | } | |
32 | else if (BRANCHTYPE(NTYPE(tch))) | |
33 | mkthen(v); | |
34 | else if (BRANCHTYPE(NTYPE(fch))) | |
35 | { | |
36 | negate(v); | |
37 | mkthen(v); | |
38 | } | |
39 | else if (NTYPE(fch) != IFVX || DEFINED(RSIB(fch))) /* not an else if */ | |
40 | if ( NTYPE(tch) == IFVX && !DEFINED(RSIB(tch))) | |
41 | /* invert into else if */ | |
42 | negate(v); | |
43 | else | |
44 | { | |
45 | /* asoc(v,n) returns number of statements associated with v | |
46 | if <= n, -1 otherwise */ | |
47 | tn = asoc(tch,MAXCHUNK); | |
48 | fn = asoc(fch,MAXCHUNK); | |
49 | if (fn >= 0 && (tn < 0 || fn < tn)) | |
50 | /* else clause smaller */ | |
51 | negate(v); | |
52 | } | |
53 | } | |
54 | RECURSE(getthen,v,recvar); | |
55 | } | |
56 | ||
57 | mkthen(v) | |
58 | VERT v; | |
59 | { | |
60 | VERT w,tc; | |
61 | w = LCHILD(v,ELSE); | |
62 | tc = LCHILD(v,THEN); | |
63 | ASSERT(!DEFINED(w) || (DEFINED(tc) && BRANCHTYPE(NTYPE(tc)) ),mkthen); | |
64 | if (DEFINED(w)) | |
65 | { | |
66 | insib(v,w); | |
67 | LCHILD(v,ELSE) = UNDEFINED; | |
68 | } | |
69 | ASSERT(IFTHEN(v),mkthen); | |
70 | } | |
71 | ||
72 | ||
73 | negate(v) | |
74 | VERT v; | |
75 | { | |
76 | ASSERT(NTYPE(v) == IFVX,negate); | |
77 | exchange(&LCHILD(v,THEN), &LCHILD(v,ELSE)); | |
78 | NEG(v) = !NEG(v); | |
79 | } |