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revision 1148, Fri Mar 15 21:38:57 2002 UTC revision 1171, Fri Mar 22 20:41:43 2002 UTC
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13  Description:  Description:
14    
15  ----------------------------------------------------------------------  ----------------------------------------------------------------------
16    Name: Lal George
17    Date: 2002/03/22 14:18:25 EST
18    Tag: george-20020322-cps-branch-prob
19    Description:
20    
21    Implemented the Ball-Larus branch prediction-heuristics, and
22    incorporated graphical viewers for control flow graphs.
23    
24    Ball-Larus Heuristics:
25    ---------------------
26    See the file compiler/CodeGen/cpscompile/cpsBranchProb.sml.
27    
28    By design it uses the Dempster-Shafer theory for combining
29    probabilities.  For example, in the function:
30    
31        fun f(n,acc) = if n = 0 then acc else f(n-1, n*acc)
32    
33    the ball-larus heuristics predicts that the n=0 is unlikely
34    (OH-heuristic), and the 'then' branch is unlikely because of the
35    RH-heuristic -- giving the 'then' branch an even lower combined
36    probability using the Dempster-Shafer theory.
37    
38    Finally, John Reppy's loop analysis in MLRISC, further lowers the
39    probability of the 'then' branch because of the loop in the else
40    branch.
41    
42    
43    Graphical Viewing:
44    ------------------
45    I merely plugged in Allen's graphical viewers into the compiler. The
46    additional code is not much. At the top level, saying:
47    
48            Control.MLRISC.getFlag "cfg-graphical-view" := true;
49    
50    will display the graphical view of the control flow graph just before
51    back-patching.  daVinci must be in your path for this to work. If
52    daVinci is not available, then the default viewer can be changed
53    using:
54    
55            Control.MLRISC.getString "viewer"
56    
57    which can be set to "dot" or "vcg" for the corresponding viewers. Of
58    course, these viewers must be in your path.
59    
60    The above will display the compilation unit at the level of clusters,
61    many of which are small, boring, and un-interesting. Also setting:
62    
63            Control.MLRISC.getInt "cfg-graphical-view_size"
64    
65    will display clusters that are larger than the value set by the above.
66    
67    
68    ----------------------------------------------------------------------
69    Name: Matthias Blume
70    Date: 2002/03/21 22:20:00 EST
71    Tag: blume-20020321-kmp-bugfix
72    Description:
73    
74    Changed the interface to the KMP routine in PreString and fixed
75    a minor bug in one place where it was used.
76    
77    ----------------------------------------------------------------------
78    Name: Allen Leung
79    Date: 2002/03/21 20:30:00 EST
80    Tag: leunga-20020321-cfg
81    Description:
82    
83      Fixed a potential problem in cfg edge splitting.
84    
85    ----------------------------------------------------------------------
86    Name: Allen Leung
87    Date: 2002/03/21 17:15:00 EST
88    Tag: leunga-20020321-x86-fp-cfg
89    Description:
90    
91      1. Recoded the buggy parts of x86-fp.
92    
93         a. All the block reordering code has been removed.
94            We now depend on the block placement phases to do this work.
95    
96         b. Critical edge splitting code has been simplified and moved into the
97            CFG modules, as where they belong.
98    
99         Both of these were quite buggy and complex.  The code is now much, much
100         simpler.
101    
102      2. X86 backend.
103    
104         a. Added instructions for 64-bit support.  Instruction selection for
105            64-bit has not been committed, however, since that
106            requires changes to MLTREE which haven't been approved by
107            Lal and John.
108    
109         b. Added support for FUCOMI and FUCOMIP when generating code for
110            PentiumPro and above.  We only generate these instructions in
111            the fast-fp mode.
112    
113         c. Added cases for JP and JNP in X86FreqProps.
114    
115      3. CFG
116    
117         CFG now has a bunch of methods for edge splitting and merging.
118    
119      4. Machine description.
120    
121         John's simplification of MLTREE_BASIS.fcond broke a few machine
122         description things:
123    
124         rtl-build.{sig,sml} and hppa.mdl fixed.
125    
126         NOTE: the machine description stuff in the repository is still broken.
127               Again, I can't put my fixes in because that involves
128               changes to MLTREE.
129    
130    ----------------------------------------------------------------------
131    Name: Matthias Blume
132    Date: 2002/03/20 15:55:00 EST
133    Tag: blume-20020320-kmp
134    Description:
135    
136    Implemented Knuth-Morris-Pratt string matching in PreString and used
137    it for String.isSubstring, Substring.isSubstring, and
138    Substring.position.
139    
140    (Might need some stress-testing.  Simple examples worked fine.)
141    
142    ----------------------------------------------------------------------
143    Name: Matthias Blume
144    Date: 2002/03/19 16:37:00 EST
145    Tag: blume-20020319-witnesses
146    Description:
147    
148    Added a structure C.W and functions convert/Ptr.convert to ml-nlffi-lib.
149    
150    This implements a generic mechanism for changing constness qualifiers
151    anywhere within big C types without resorting to outright "casts".
152    (So far, functions such as C.rw/C.ro or C.Ptr.rw/C.Ptr.ro only let you
153    modify the constness at the outermost level.)
154    The implementation of "convert" is based on the idea of "witness"
155    values -- values that are not used by the operation but whose types
156    "testify" to their applicability.  On the implementation side, "convert"
157    is simply a projection (returning its second curried argument).  With
158    cross-module inlining, it should not result in any machine code being
159    generated.
160    
161    ----------------------------------------------------------------------
162  Name: Matthias Blume  Name: Matthias Blume
163  Date: 2002/03/15 16:40:00 EST  Date: 2002/03/15 16:40:00 EST
164  Tag: blume-20020315-basis  Tag: blume-20020315-basis

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