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Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]11<!--
12
13If Passes.html is up to date, the following "one-liner" should print
14an empty diff.
15
16egrep -e '^<tr><td><a href="#.*">-.*</a></td><td>.*</td></tr>$' \
17 -e '^ <a name=".*">.*</a>$' < Passes.html >html; \
18perl >help <<'EOT' && diff -u help html; rm -f help html
19open HTML, "<Passes.html" or die "open: Passes.html: $!\n";
20while (<HTML>) {
21 m:^<tr><td><a href="#(.*)">-.*</a></td><td>.*</td></tr>$: or next;
22 $order{$1} = sprintf("%03d", 1 + int %order);
23}
Gordon Henriksenddaa61d2007-10-25 08:58:56 +0000[diff] [blame]24open HELP, "../Release/bin/opt -help|" or die "open: opt -help: $!\n";
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]25while (<HELP>) {
26 m:^ -([^ ]+) +- (.*)$: or next;
27 my $o = $order{$1};
28 $o = "000" unless defined $o;
29 push @x, "$o<tr><td><a href=\"#$1\">-$1</a></td><td>$2</td></tr>\n";
30 push @y, "$o <a name=\"$1\">$2</a>\n";
31}
32@x = map { s/^\d\d\d//; $_ } sort @x;
33@y = map { s/^\d\d\d//; $_ } sort @y;
34print @x, @y;
35EOT
36
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]37This (real) one-liner can also be helpful when converting comments to HTML:
38
39perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if !$on && $_ =~ /\S/; print " </p>\n" if $on && $_ =~ /^\s*$/; print " $_\n"; $on = ($_ =~ /\S/); } print " </p>\n" if $on'
40
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]41 -->
42
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]43<div class="doc_title">LLVM's Analysis and Transform Passes</div>
44
45<ol>
46 <li><a href="#intro">Introduction</a></li>
47 <li><a href="#analyses">Analysis Passes</a>
48 <li><a href="#transforms">Transform Passes</a></li>
49 <li><a href="#utilities">Utility Passes</a></li>
50</ol>
51
52<div class="doc_author">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]53 <p>Written by <a href="mailto:rspencer@x10sys.com">Reid Spencer</a>
54 and Gordon Henriksen</p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]55</div>
56
57<!-- ======================================================================= -->
58<div class="doc_section"> <a name="intro">Introduction</a> </div>
59<div class="doc_text">
60 <p>This document serves as a high level summary of the optimization features
61 that LLVM provides. Optimizations are implemented as Passes that traverse some
62 portion of a program to either collect information or transform the program.
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]63 The table below divides the passes that LLVM provides into three categories.
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]64 Analysis passes compute information that other passes can use or for debugging
65 or program visualization purposes. Transform passes can use (or invalidate)
66 the analysis passes. Transform passes all mutate the program in some way.
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]67 Utility passes provides some utility but don't otherwise fit categorization.
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]68 For example passes to extract functions to bitcode or write a module to
69 bitcode are neither analysis nor transform passes.
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]70 <p>The table below provides a quick summary of each pass and links to the more
71 complete pass description later in the document.</p>
72</div>
73<div class="doc_text" >
74<table>
Gordon Henriksenddaa61d2007-10-25 08:58:56 +0000[diff] [blame]75<tr><th colspan="2"><b>ANALYSIS PASSES</b></th></tr>
76<tr><th>Option</th><th>Name</th></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]77<tr><td><a href="#aa-eval">-aa-eval</a></td><td>Exhaustive Alias Analysis Precision Evaluator</td></tr>
78<tr><td><a href="#anders-aa">-anders-aa</a></td><td>Andersen's Interprocedural Alias Analysis</td></tr>
79<tr><td><a href="#basicaa">-basicaa</a></td><td>Basic Alias Analysis (default AA impl)</td></tr>
80<tr><td><a href="#basiccg">-basiccg</a></td><td>Basic CallGraph Construction</td></tr>
81<tr><td><a href="#basicvn">-basicvn</a></td><td>Basic Value Numbering (default GVN impl)</td></tr>
82<tr><td><a href="#callgraph">-callgraph</a></td><td>Print a call graph</td></tr>
83<tr><td><a href="#callscc">-callscc</a></td><td>Print SCCs of the Call Graph</td></tr>
84<tr><td><a href="#cfgscc">-cfgscc</a></td><td>Print SCCs of each function CFG</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]85<tr><td><a href="#codegenprepare">-codegenprepare</a></td><td>Optimize for code generation</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]86<tr><td><a href="#count-aa">-count-aa</a></td><td>Count Alias Analysis Query Responses</td></tr>
87<tr><td><a href="#debug-aa">-debug-aa</a></td><td>AA use debugger</td></tr>
88<tr><td><a href="#domfrontier">-domfrontier</a></td><td>Dominance Frontier Construction</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]89<tr><td><a href="#domtree">-domtree</a></td><td>Dominator Tree Construction</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]90<tr><td><a href="#externalfnconstants">-externalfnconstants</a></td><td>Print external fn callsites passed constants</td></tr>
91<tr><td><a href="#globalsmodref-aa">-globalsmodref-aa</a></td><td>Simple mod/ref analysis for globals</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]92<tr><td><a href="#instcount">-instcount</a></td><td>Counts the various types of Instructions</td></tr>
93<tr><td><a href="#intervals">-intervals</a></td><td>Interval Partition Construction</td></tr>
94<tr><td><a href="#load-vn">-load-vn</a></td><td>Load Value Numbering</td></tr>
95<tr><td><a href="#loops">-loops</a></td><td>Natural Loop Construction</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]96<tr><td><a href="#memdep">-memdep</a></td><td>Memory Dependence Analysis</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]97<tr><td><a href="#no-aa">-no-aa</a></td><td>No Alias Analysis (always returns 'may' alias)</td></tr>
98<tr><td><a href="#no-profile">-no-profile</a></td><td>No Profile Information</td></tr>
99<tr><td><a href="#postdomfrontier">-postdomfrontier</a></td><td>Post-Dominance Frontier Construction</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]100<tr><td><a href="#postdomtree">-postdomtree</a></td><td>Post-Dominator Tree Construction</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]101<tr><td><a href="#print">-print</a></td><td>Print function to stderr</td></tr>
102<tr><td><a href="#print-alias-sets">-print-alias-sets</a></td><td>Alias Set Printer</td></tr>
103<tr><td><a href="#print-callgraph">-print-callgraph</a></td><td>Print Call Graph to 'dot' file</td></tr>
104<tr><td><a href="#print-cfg">-print-cfg</a></td><td>Print CFG of function to 'dot' file</td></tr>
105<tr><td><a href="#print-cfg-only">-print-cfg-only</a></td><td>Print CFG of function to 'dot' file (with no function bodies)</td></tr>
106<tr><td><a href="#printm">-printm</a></td><td>Print module to stderr</td></tr>
107<tr><td><a href="#printusedtypes">-printusedtypes</a></td><td>Find Used Types</td></tr>
108<tr><td><a href="#profile-loader">-profile-loader</a></td><td>Load profile information from llvmprof.out</td></tr>
109<tr><td><a href="#scalar-evolution">-scalar-evolution</a></td><td>Scalar Evolution Analysis</td></tr>
110<tr><td><a href="#targetdata">-targetdata</a></td><td>Target Data Layout</td></tr>
111
112
Gordon Henriksenddaa61d2007-10-25 08:58:56 +0000[diff] [blame]113<tr><th colspan="2"><b>TRANSFORM PASSES</b></th></tr>
114<tr><th>Option</th><th>Name</th></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]115<tr><td><a href="#adce">-adce</a></td><td>Aggressive Dead Code Elimination</td></tr>
116<tr><td><a href="#argpromotion">-argpromotion</a></td><td>Promote 'by reference' arguments to scalars</td></tr>
117<tr><td><a href="#block-placement">-block-placement</a></td><td>Profile Guided Basic Block Placement</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]118<tr><td><a href="#break-crit-edges">-break-crit-edges</a></td><td>Break critical edges in CFG</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]119<tr><td><a href="#cee">-cee</a></td><td>Correlated Expression Elimination</td></tr>
120<tr><td><a href="#condprop">-condprop</a></td><td>Conditional Propagation</td></tr>
121<tr><td><a href="#constmerge">-constmerge</a></td><td>Merge Duplicate Global Constants</td></tr>
122<tr><td><a href="#constprop">-constprop</a></td><td>Simple constant propagation</td></tr>
123<tr><td><a href="#dce">-dce</a></td><td>Dead Code Elimination</td></tr>
124<tr><td><a href="#deadargelim">-deadargelim</a></td><td>Dead Argument Elimination</td></tr>
125<tr><td><a href="#deadtypeelim">-deadtypeelim</a></td><td>Dead Type Elimination</td></tr>
126<tr><td><a href="#die">-die</a></td><td>Dead Instruction Elimination</td></tr>
127<tr><td><a href="#dse">-dse</a></td><td>Dead Store Elimination</td></tr>
128<tr><td><a href="#gcse">-gcse</a></td><td>Global Common Subexpression Elimination</td></tr>
129<tr><td><a href="#globaldce">-globaldce</a></td><td>Dead Global Elimination</td></tr>
130<tr><td><a href="#globalopt">-globalopt</a></td><td>Global Variable Optimizer</td></tr>
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]131<tr><td><a href="#gvn">-gvn</a></td><td>Global Value Numbering</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]132<tr><td><a href="#gvnpre">-gvnpre</a></td><td>Global Value Numbering/Partial Redundancy Elimination</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]133<tr><td><a href="#indmemrem">-indmemrem</a></td><td>Indirect Malloc and Free Removal</td></tr>
134<tr><td><a href="#indvars">-indvars</a></td><td>Canonicalize Induction Variables</td></tr>
135<tr><td><a href="#inline">-inline</a></td><td>Function Integration/Inlining</td></tr>
136<tr><td><a href="#insert-block-profiling">-insert-block-profiling</a></td><td>Insert instrumentation for block profiling</td></tr>
137<tr><td><a href="#insert-edge-profiling">-insert-edge-profiling</a></td><td>Insert instrumentation for edge profiling</td></tr>
138<tr><td><a href="#insert-function-profiling">-insert-function-profiling</a></td><td>Insert instrumentation for function profiling</td></tr>
139<tr><td><a href="#insert-null-profiling-rs">-insert-null-profiling-rs</a></td><td>Measure profiling framework overhead</td></tr>
140<tr><td><a href="#insert-rs-profiling-framework">-insert-rs-profiling-framework</a></td><td>Insert random sampling instrumentation framework</td></tr>
141<tr><td><a href="#instcombine">-instcombine</a></td><td>Combine redundant instructions</td></tr>
142<tr><td><a href="#internalize">-internalize</a></td><td>Internalize Global Symbols</td></tr>
143<tr><td><a href="#ipconstprop">-ipconstprop</a></td><td>Interprocedural constant propagation</td></tr>
144<tr><td><a href="#ipsccp">-ipsccp</a></td><td>Interprocedural Sparse Conditional Constant Propagation</td></tr>
145<tr><td><a href="#lcssa">-lcssa</a></td><td>Loop-Closed SSA Form Pass</td></tr>
146<tr><td><a href="#licm">-licm</a></td><td>Loop Invariant Code Motion</td></tr>
147<tr><td><a href="#loop-extract">-loop-extract</a></td><td>Extract loops into new functions</td></tr>
148<tr><td><a href="#loop-extract-single">-loop-extract-single</a></td><td>Extract at most one loop into a new function</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]149<tr><td><a href="#loop-index-split">-loop-index-split</a></td><td>Index Split Loops</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]150<tr><td><a href="#loop-reduce">-loop-reduce</a></td><td>Loop Strength Reduction</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]151<tr><td><a href="#loop-rotate">-loop-rotate</a></td><td>Rotate Loops</td></tr>
152<tr><td><a href="#loop-unroll">-loop-unroll</a></td><td>Unroll loops</td></tr>
153<tr><td><a href="#loop-unswitch">-loop-unswitch</a></td><td>Unswitch loops</td></tr>
154<tr><td><a href="#loopsimplify">-loopsimplify</a></td><td>Canonicalize natural loops</td></tr>
155<tr><td><a href="#lower-packed">-lower-packed</a></td><td>lowers packed operations to operations on smaller packed datatypes</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]156<tr><td><a href="#lowerallocs">-lowerallocs</a></td><td>Lower allocations from instructions to calls</td></tr>
157<tr><td><a href="#lowergc">-lowergc</a></td><td>Lower GC intrinsics, for GCless code generators</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]158<tr><td><a href="#lowerinvoke">-lowerinvoke</a></td><td>Lower invoke and unwind, for unwindless code generators</td></tr>
159<tr><td><a href="#lowerselect">-lowerselect</a></td><td>Lower select instructions to branches</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]160<tr><td><a href="#lowersetjmp">-lowersetjmp</a></td><td>Lower Set Jump</td></tr>
161<tr><td><a href="#lowerswitch">-lowerswitch</a></td><td>Lower SwitchInst's to branches</td></tr>
162<tr><td><a href="#mem2reg">-mem2reg</a></td><td>Promote Memory to Register</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]163<tr><td><a href="#mergereturn">-mergereturn</a></td><td>Unify function exit nodes</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]164<tr><td><a href="#predsimplify">-predsimplify</a></td><td>Predicate Simplifier</td></tr>
165<tr><td><a href="#prune-eh">-prune-eh</a></td><td>Remove unused exception handling info</td></tr>
166<tr><td><a href="#raiseallocs">-raiseallocs</a></td><td>Raise allocations from calls to instructions</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]167<tr><td><a href="#reassociate">-reassociate</a></td><td>Reassociate expressions</td></tr>
168<tr><td><a href="#reg2mem">-reg2mem</a></td><td>Demote all values to stack slots</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]169<tr><td><a href="#scalarrepl">-scalarrepl</a></td><td>Scalar Replacement of Aggregates</td></tr>
170<tr><td><a href="#sccp">-sccp</a></td><td>Sparse Conditional Constant Propagation</td></tr>
171<tr><td><a href="#simplify-libcalls">-simplify-libcalls</a></td><td>Simplify well-known library calls</td></tr>
172<tr><td><a href="#simplifycfg">-simplifycfg</a></td><td>Simplify the CFG</td></tr>
173<tr><td><a href="#strip">-strip</a></td><td>Strip all symbols from a module</td></tr>
174<tr><td><a href="#tailcallelim">-tailcallelim</a></td><td>Tail Call Elimination</td></tr>
175<tr><td><a href="#tailduplicate">-tailduplicate</a></td><td>Tail Duplication</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]176
177
Gordon Henriksenddaa61d2007-10-25 08:58:56 +0000[diff] [blame]178<tr><th colspan="2"><b>UTILITY PASSES</b></th></tr>
179<tr><th>Option</th><th>Name</th></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]180<tr><td><a href="#deadarghaX0r">-deadarghaX0r</a></td><td>Dead Argument Hacking (BUGPOINT USE ONLY; DO NOT USE)</td></tr>
181<tr><td><a href="#extract-blocks">-extract-blocks</a></td><td>Extract Basic Blocks From Module (for bugpoint use)</td></tr>
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]182<tr><td><a href="#emitbitcode">-emitbitcode</a></td><td>Bitcode Writer</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]183<tr><td><a href="#verify">-verify</a></td><td>Module Verifier</td></tr>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]184<tr><td><a href="#view-cfg">-view-cfg</a></td><td>View CFG of function</td></tr>
185<tr><td><a href="#view-cfg-only">-view-cfg-only</a></td><td>View CFG of function (with no function bodies)</td></tr>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]186</table>
187</div>
188
189<!-- ======================================================================= -->
190<div class="doc_section"> <a name="example">Analysis Passes</a></div>
191<div class="doc_text">
192 <p>This section describes the LLVM Analysis Passes.</p>
193</div>
194
195<!-------------------------------------------------------------------------- -->
196<div class="doc_subsection">
197 <a name="aa-eval">Exhaustive Alias Analysis Precision Evaluator</a>
198</div>
199<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]200 <p>This is a simple N^2 alias analysis accuracy evaluator.
201 Basically, for each function in the program, it simply queries to see how the
202 alias analysis implementation answers alias queries between each pair of
203 pointers in the function.</p>
204
205 <p>This is inspired and adapted from code by: Naveen Neelakantam, Francesco
206 Spadini, and Wojciech Stryjewski.</p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]207</div>
208
209<!-------------------------------------------------------------------------- -->
210<div class="doc_subsection">
211 <a name="anders-aa">Andersen's Interprocedural Alias Analysis</a>
212</div>
213<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]214 <p>
215 This is an implementation of Andersen's interprocedural alias
216 analysis
217 </p>
218
219 <p>
220 In pointer analysis terms, this is a subset-based, flow-insensitive,
221 field-sensitive, and context-insensitive algorithm pointer algorithm.
222 </p>
223
224 <p>
225 This algorithm is implemented as three stages:
226 </p>
227
228 <ol>
229 <li>Object identification.</li>
230 <li>Inclusion constraint identification.</li>
231 <li>Offline constraint graph optimization.</li>
232 <li>Inclusion constraint solving.</li>
233 </ol>
234
235 <p>
236 The object identification stage identifies all of the memory objects in the
237 program, which includes globals, heap allocated objects, and stack allocated
238 objects.
239 </p>
240
241 <p>
242 The inclusion constraint identification stage finds all inclusion constraints
243 in the program by scanning the program, looking for pointer assignments and
244 other statements that effect the points-to graph. For a statement like
245 <code><var>A</var> = <var>B</var></code>, this statement is processed to
246 indicate that <var>A</var> can point to anything that <var>B</var> can point
247 to. Constraints can handle copies, loads, and stores, and address taking.
248 </p>
249
250 <p>
251 The offline constraint graph optimization portion includes offline variable
252 substitution algorithms intended to computer pointer and location
253 equivalences. Pointer equivalences are those pointers that will have the
254 same points-to sets, and location equivalences are those variables that
255 always appear together in points-to sets.
256 </p>
257
258 <p>
259 The inclusion constraint solving phase iteratively propagates the inclusion
260 constraints until a fixed point is reached. This is an O(<var>n</var>³)
261 algorithm.
262 </p>
263
264 <p>
265 Function constraints are handled as if they were structs with <var>X</var>
266 fields. Thus, an access to argument <var>X</var> of function <var>Y</var> is
267 an access to node index <code>getNode(<var>Y</var>) + <var>X</var></code>.
268 This representation allows handling of indirect calls without any issues. To
269 wit, an indirect call <code><var>Y</var>(<var>a</var>,<var>b</var>)</code> is
270 equivalent to <code>*(<var>Y</var> + 1) = <var>a</var>, *(<var>Y</var> + 2) =
271 <var>b</var></code>. The return node for a function <var>F</var> is always
272 located at <code>getNode(<var>F</var>) + CallReturnPos</code>. The arguments
273 start at <code>getNode(<var>F</var>) + CallArgPos</code>.
274 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]275</div>
276
277<!-------------------------------------------------------------------------- -->
278<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]279 <a name="basicaa">Basic Alias Analysis (default AA impl)</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]280</div>
281<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]282 <p>
283 This is the default implementation of the Alias Analysis interface
284 that simply implements a few identities (two different globals cannot alias,
285 etc), but otherwise does no analysis.
286 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]287</div>
288
289<!-------------------------------------------------------------------------- -->
290<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]291 <a name="basiccg">Basic CallGraph Construction</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]292</div>
293<div class="doc_text">
294 <p>Yet to be written.</p>
295</div>
296
297<!-------------------------------------------------------------------------- -->
298<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]299 <a name="basicvn">Basic Value Numbering (default GVN impl)</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]300</div>
301<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]302 <p>
303 This is the default implementation of the <code>ValueNumbering</code>
304 interface. It walks the SSA def-use chains to trivially identify
305 lexically identical expressions. This does not require any ahead of time
306 analysis, so it is a very fast default implementation.
307 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]308</div>
309
310<!-------------------------------------------------------------------------- -->
311<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]312 <a name="callgraph">Print a call graph</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]313</div>
314<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]315 <p>
316 This pass, only available in <code>opt</code>, prints
317 the call graph into a <code>.dot</code> graph. This graph can then be processed with the
318 "dot" tool to convert it to postscript or some other suitable format.
319 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]320</div>
321
322<!-------------------------------------------------------------------------- -->
323<div class="doc_subsection">
324 <a name="callscc">Print SCCs of the Call Graph</a>
325</div>
326<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]327 <p>
328 This pass, only available in <code>opt</code>, prints
329 the SCCs of the call graph to standard output in a human-readable form.
330 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]331</div>
332
333<!-------------------------------------------------------------------------- -->
334<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]335 <a name="cfgscc">Print SCCs of each function CFG</a>
336</div>
337<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]338 <p>
339 This pass, only available in <code>opt</code>, prints
340 the SCCs of each function CFG to standard output in a human-readable form.
341 </p>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]342</div>
343
344<!-------------------------------------------------------------------------- -->
345<div class="doc_subsection">
346 <a name="codegenprepare">Optimize for code generation</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]347</div>
348<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]349 <p>
350 This pass munges the code in the input function to better prepare it for
351 SelectionDAG-based code generation. This works around limitations in it's
352 basic-block-at-a-time approach. It should eventually be removed.
353 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]354</div>
355
356<!-------------------------------------------------------------------------- -->
357<div class="doc_subsection">
358 <a name="count-aa">Count Alias Analysis Query Responses</a>
359</div>
360<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]361 <p>
362 A pass which can be used to count how many alias queries
363 are being made and how the alias analysis implementation being used responds.
364 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]365</div>
366
367<!-------------------------------------------------------------------------- -->
368<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]369 <a name="debug-aa">AA use debugger</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]370</div>
371<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]372 <p>
373 This simple pass checks alias analysis users to ensure that if they
374 create a new value, they do not query AA without informing it of the value.
375 It acts as a shim over any other AA pass you want.
376 </p>
377
378 <p>
379 Yes keeping track of every value in the program is expensive, but this is
380 a debugging pass.
381 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]382</div>
383
384<!-------------------------------------------------------------------------- -->
385<div class="doc_subsection">
386 <a name="domfrontier">Dominance Frontier Construction</a>
387</div>
388<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]389 <p>
390 This pass is a simple dominator construction algorithm for finding forward
391 dominator frontiers.
392 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]393</div>
394
395<!-------------------------------------------------------------------------- -->
396<div class="doc_subsection">
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]397 <a name="domtree">Dominator Tree Construction</a>
398</div>
399<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]400 <p>
401 This pass is a simple dominator construction algorithm for finding forward
402 dominators.
403 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]404</div>
405
406<!-------------------------------------------------------------------------- -->
407<div class="doc_subsection">
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]408 <a name="externalfnconstants">Print external fn callsites passed constants</a>
409</div>
410<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]411 <p>
412 This pass, only available in <code>opt</code>, prints out call sites to
413 external functions that are called with constant arguments. This can be
414 useful when looking for standard library functions we should constant fold
415 or handle in alias analyses.
416 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]417</div>
418
419<!-------------------------------------------------------------------------- -->
420<div class="doc_subsection">
421 <a name="globalsmodref-aa">Simple mod/ref analysis for globals</a>
422</div>
423<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]424 <p>
425 This simple pass provides alias and mod/ref information for global values
426 that do not have their address taken, and keeps track of whether functions
427 read or write memory (are "pure"). For this simple (but very common) case,
428 we can provide pretty accurate and useful information.
429 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]430</div>
431
432<!-------------------------------------------------------------------------- -->
433<div class="doc_subsection">
434 <a name="instcount">Counts the various types of Instructions</a>
435</div>
436<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]437 <p>
438 This pass collects the count of all instructions and reports them
439 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]440</div>
441
442<!-------------------------------------------------------------------------- -->
443<div class="doc_subsection">
444 <a name="intervals">Interval Partition Construction</a>
445</div>
446<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]447 <p>
448 This analysis calculates and represents the interval partition of a function,
449 or a preexisting interval partition.
450 </p>
451
452 <p>
453 In this way, the interval partition may be used to reduce a flow graph down
454 to its degenerate single node interval partition (unless it is irreducible).
455 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]456</div>
457
458<!-------------------------------------------------------------------------- -->
459<div class="doc_subsection">
460 <a name="load-vn">Load Value Numbering</a>
461</div>
462<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]463 <p>
464 This pass value numbers load and call instructions. To do this, it finds
465 lexically identical load instructions, and uses alias analysis to determine
466 which loads are guaranteed to produce the same value. To value number call
467 instructions, it looks for calls to functions that do not write to memory
468 which do not have intervening instructions that clobber the memory that is
469 read from.
470 </p>
471
472 <p>
473 This pass builds off of another value numbering pass to implement value
474 numbering for non-load and non-call instructions. It uses Alias Analysis so
475 that it can disambiguate the load instructions. The more powerful these base
476 analyses are, the more powerful the resultant value numbering will be.
477 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]478</div>
479
480<!-------------------------------------------------------------------------- -->
481<div class="doc_subsection">
482 <a name="loops">Natural Loop Construction</a>
483</div>
484<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]485 <p>
486 This analysis is used to identify natural loops and determine the loop depth
487 of various nodes of the CFG. Note that the loops identified may actually be
488 several natural loops that share the same header node... not just a single
489 natural loop.
490 </p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]491</div>
492
493<!-------------------------------------------------------------------------- -->
494<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]495 <a name="memdep">Memory Dependence Analysis</a>
496</div>
497<div class="doc_text">
498 <p>Yet to be written.</p>
499</div>
500
501<!-------------------------------------------------------------------------- -->
502<div class="doc_subsection">
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]503 <a name="no-aa">No Alias Analysis (always returns 'may' alias)</a>
504</div>
505<div class="doc_text">
506 <p>Yet to be written.</p>
507</div>
508
509<!-------------------------------------------------------------------------- -->
510<div class="doc_subsection">
511 <a name="no-profile">No Profile Information</a>
512</div>
513<div class="doc_text">
514 <p>Yet to be written.</p>
515</div>
516
517<!-------------------------------------------------------------------------- -->
518<div class="doc_subsection">
519 <a name="postdomfrontier">Post-Dominance Frontier Construction</a>
520</div>
521<div class="doc_text">
522 <p>Yet to be written.</p>
523</div>
524
525<!-------------------------------------------------------------------------- -->
526<div class="doc_subsection">
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]527 <a name="postdomtree">Post-Dominator Tree Construction</a>
528</div>
529<div class="doc_text">
530 <p>Yet to be written.</p>
531</div>
532
533<!-------------------------------------------------------------------------- -->
534<div class="doc_subsection">
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]535 <a name="print">Print function to stderr</a>
536</div>
537<div class="doc_text">
538 <p>Yet to be written.</p>
539</div>
540
541<!-------------------------------------------------------------------------- -->
542<div class="doc_subsection">
543 <a name="print-alias-sets">Alias Set Printer</a>
544</div>
545<div class="doc_text">
546 <p>Yet to be written.</p>
547</div>
548
549<!-------------------------------------------------------------------------- -->
550<div class="doc_subsection">
551 <a name="print-callgraph">Print Call Graph to 'dot' file</a>
552</div>
553<div class="doc_text">
554 <p>Yet to be written.</p>
555</div>
556
557<!-------------------------------------------------------------------------- -->
558<div class="doc_subsection">
559 <a name="print-cfg">Print CFG of function to 'dot' file</a>
560</div>
561<div class="doc_text">
562 <p>Yet to be written.</p>
563</div>
564
565<!-------------------------------------------------------------------------- -->
566<div class="doc_subsection">
567 <a name="print-cfg-only">Print CFG of function to 'dot' file (with no function bodies)</a>
568</div>
569<div class="doc_text">
570 <p>Yet to be written.</p>
571</div>
572
573<!-------------------------------------------------------------------------- -->
574<div class="doc_subsection">
575 <a name="printm">Print module to stderr</a>
576</div>
577<div class="doc_text">
578 <p>Yet to be written.</p>
579</div>
580
581<!-------------------------------------------------------------------------- -->
582<div class="doc_subsection">
583 <a name="printusedtypes">Find Used Types</a>
584</div>
585<div class="doc_text">
586 <p>Yet to be written.</p>
587</div>
588
589<!-------------------------------------------------------------------------- -->
590<div class="doc_subsection">
591 <a name="profile-loader">Load profile information from llvmprof.out</a>
592</div>
593<div class="doc_text">
594 <p>Yet to be written.</p>
595</div>
596
597<!-------------------------------------------------------------------------- -->
598<div class="doc_subsection">
599 <a name="scalar-evolution">Scalar Evolution Analysis</a>
600</div>
601<div class="doc_text">
602 <p>Yet to be written.</p>
603</div>
604
605<!-------------------------------------------------------------------------- -->
606<div class="doc_subsection">
607 <a name="targetdata">Target Data Layout</a>
608</div>
609<div class="doc_text">
610 <p>Yet to be written.</p>
611</div>
612
613<!-- ======================================================================= -->
614<div class="doc_section"> <a name="transform">Transform Passes</a></div>
615<div class="doc_text">
616 <p>This section describes the LLVM Transform Passes.</p>
617</div>
618
619<!-------------------------------------------------------------------------- -->
620<div class="doc_subsection">
621 <a name="adce">Aggressive Dead Code Elimination</a>
622</div>
623<div class="doc_text">
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]624 <p>ADCE aggressively tries to eliminate code. This pass is similar to
625 <a href="#dce">DCE</a> but it assumes that values are dead until proven
626 otherwise. This is similar to <a href="#sccp">SCCP</a>, except applied to
627 the liveness of values.</p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]628</div>
629
630<!-------------------------------------------------------------------------- -->
631<div class="doc_subsection">
632 <a name="argpromotion">Promote 'by reference' arguments to scalars</a>
633</div>
634<div class="doc_text">
635 <p>Yet to be written.</p>
636</div>
637
638<!-------------------------------------------------------------------------- -->
639<div class="doc_subsection">
640 <a name="block-placement">Profile Guided Basic Block Placement</a>
641</div>
642<div class="doc_text">
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]643 <p>This pass implements a very simple profile guided basic block placement
644 algorithm. The idea is to put frequently executed blocks together at the
645 start of the function, and hopefully increase the number of fall-through
646 conditional branches. If there is no profile information for a particular
647 function, this pass basically orders blocks in depth-first order.</p>
648 <p>The algorithm implemented here is basically "Algo1" from "Profile Guided
649 Code Positioning" by Pettis and Hansen, except that it uses basic block
650 counts instead of edge counts. This could be improved in many ways, but is
651 very simple for now.</p>
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]652
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]653 <p>Basically we "place" the entry block, then loop over all successors in a
654 DFO, placing the most frequently executed successor until we run out of
655 blocks. Did we mention that this was <b>extremely</b> simplistic? This is
656 also much slower than it could be. When it becomes important, this pass
657 will be rewritten to use a better algorithm, and then we can worry about
658 efficiency.</p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]659</div>
660
661<!-------------------------------------------------------------------------- -->
662<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]663 <a name="break-crit-edges">Break critical edges in CFG</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]664</div>
665<div class="doc_text">
666 <p>Yet to be written.</p>
667</div>
668
669<!-------------------------------------------------------------------------- -->
670<div class="doc_subsection">
671 <a name="cee">Correlated Expression Elimination</a>
672</div>
673<div class="doc_text">
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]674 <p>Correlated Expression Elimination propagates information from conditional
675 branches to blocks dominated by destinations of the branch. It propagates
676 information from the condition check itself into the body of the branch,
Gordon Henriksenddaa61d2007-10-25 08:58:56 +0000[diff] [blame]677 allowing transformations like these for example:</p>
678
679<blockquote><pre>
680if (i == 7)
681 ... 4*i; // constant propagation
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]682
Gordon Henriksenddaa61d2007-10-25 08:58:56 +0000[diff] [blame]683M = i+1; N = j+1;
684if (i == j)
685 X = M-N; // = M-M == 0;
686</pre></blockquote>
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]687
688 <p>This is called Correlated Expression Elimination because we eliminate or
689 simplify expressions that are correlated with the direction of a branch. In
690 this way we use static information to give us some information about the
691 dynamic value of a variable.</p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]692</div>
693
694<!-------------------------------------------------------------------------- -->
695<div class="doc_subsection">
696 <a name="condprop">Conditional Propagation</a>
697</div>
698<div class="doc_text">
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]699 <p>This pass propagates information about conditional expressions through the
700 program, allowing it to eliminate conditional branches in some cases.</p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]701</div>
702
703<!-------------------------------------------------------------------------- -->
704<div class="doc_subsection">
705 <a name="constmerge">Merge Duplicate Global Constants</a>
706</div>
707<div class="doc_text">
708 <p>Yet to be written.</p>
709</div>
710
711<!-------------------------------------------------------------------------- -->
712<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]713 <a name="constprop">Simple constant propagation</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]714</div>
715<div class="doc_text">
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]716 <p>This file implements constant propagation and merging. It looks for
717 instructions involving only constant operands and replaces them with a
Gordon Henriksenddaa61d2007-10-25 08:58:56 +0000[diff] [blame]718 constant value instead of an instruction. For example:</p>
719 <blockquote><pre>add i32 1, 2</pre></blockquote>
720 <p>becomes</p>
721 <blockquote><pre>i32 3</pre></blockquote>
Reid Spenceraf4af3a2007-03-27 02:49:31 +0000[diff] [blame]722 <p>NOTE: this pass has a habit of making definitions be dead. It is a good
723 idea to to run a <a href="#die">DIE</a> (Dead Instruction Elimination) pass
724 sometime after running this pass.</p>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]725</div>
726
727<!-------------------------------------------------------------------------- -->
728<div class="doc_subsection">
729 <a name="dce">Dead Code Elimination</a>
730</div>
731<div class="doc_text">
732 <p>Yet to be written.</p>
733</div>
734
735<!-------------------------------------------------------------------------- -->
736<div class="doc_subsection">
737 <a name="deadargelim">Dead Argument Elimination</a>
738</div>
739<div class="doc_text">
740 <p>Yet to be written.</p>
741</div>
742
743<!-------------------------------------------------------------------------- -->
744<div class="doc_subsection">
745 <a name="deadtypeelim">Dead Type Elimination</a>
746</div>
747<div class="doc_text">
748 <p>Yet to be written.</p>
749</div>
750
751<!-------------------------------------------------------------------------- -->
752<div class="doc_subsection">
753 <a name="die">Dead Instruction Elimination</a>
754</div>
755<div class="doc_text">
756 <p>Yet to be written.</p>
757</div>
758
759<!-------------------------------------------------------------------------- -->
760<div class="doc_subsection">
761 <a name="dse">Dead Store Elimination</a>
762</div>
763<div class="doc_text">
764 <p>Yet to be written.</p>
765</div>
766
767<!-------------------------------------------------------------------------- -->
768<div class="doc_subsection">
769 <a name="gcse">Global Common Subexpression Elimination</a>
770</div>
771<div class="doc_text">
772 <p>Yet to be written.</p>
773</div>
774
775<!-------------------------------------------------------------------------- -->
776<div class="doc_subsection">
777 <a name="globaldce">Dead Global Elimination</a>
778</div>
779<div class="doc_text">
780 <p>Yet to be written.</p>
781</div>
782
783<!-------------------------------------------------------------------------- -->
784<div class="doc_subsection">
785 <a name="globalopt">Global Variable Optimizer</a>
786</div>
787<div class="doc_text">
788 <p>Yet to be written.</p>
789</div>
790
791<!-------------------------------------------------------------------------- -->
792<div class="doc_subsection">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]793 <a name="gvn">Global Value Numbering</a>
794</div>
795<div class="doc_text">
796 <p>
797 This pass performs global value numbering to eliminate fully redundant
798 instructions. It also performs simple dead load elimination.
799 </p>
800</div>
801
802<!-------------------------------------------------------------------------- -->
803<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]804 <a name="gvnpre">Global Value Numbering/Partial Redundancy Elimination</a>
805</div>
806<div class="doc_text">
Gordon Henriksen0e15dc22007-10-25 10:18:27 +0000[diff] [blame^]807 <p>
808 This pass performs a hybrid of global value numbering and partial redundancy
809 elimination, known as GVN-PRE. It performs partial redundancy elimination on
810 values, rather than lexical expressions, allowing a more comprehensive view
811 the optimization. It replaces redundant values with uses of earlier
812 occurences of the same value. While this is beneficial in that it eliminates
813 unneeded computation, it also increases register pressure by creating large
814 live ranges, and should be used with caution on platforms that are very
815 sensitive to register pressure.
816 </p>
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]817</div>
818
819<!-------------------------------------------------------------------------- -->
820<div class="doc_subsection">
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]821 <a name="indmemrem">Indirect Malloc and Free Removal</a>
822</div>
823<div class="doc_text">
824 <p>Yet to be written.</p>
825</div>
826
827<!-------------------------------------------------------------------------- -->
828<div class="doc_subsection">
829 <a name="indvars">Canonicalize Induction Variables</a>
830</div>
831<div class="doc_text">
832 <p>Yet to be written.</p>
833</div>
834
835<!-------------------------------------------------------------------------- -->
836<div class="doc_subsection">
837 <a name="inline">Function Integration/Inlining</a>
838</div>
839<div class="doc_text">
840 <p>Yet to be written.</p>
841</div>
842
843<!-------------------------------------------------------------------------- -->
844<div class="doc_subsection">
845 <a name="insert-block-profiling">Insert instrumentation for block profiling</a>
846</div>
847<div class="doc_text">
848 <p>Yet to be written.</p>
849</div>
850
851<!-------------------------------------------------------------------------- -->
852<div class="doc_subsection">
853 <a name="insert-edge-profiling">Insert instrumentation for edge profiling</a>
854</div>
855<div class="doc_text">
856 <p>Yet to be written.</p>
857</div>
858
859<!-------------------------------------------------------------------------- -->
860<div class="doc_subsection">
861 <a name="insert-function-profiling">Insert instrumentation for function profiling</a>
862</div>
863<div class="doc_text">
864 <p>Yet to be written.</p>
865</div>
866
867<!-------------------------------------------------------------------------- -->
868<div class="doc_subsection">
869 <a name="insert-null-profiling-rs">Measure profiling framework overhead</a>
870</div>
871<div class="doc_text">
872 <p>Yet to be written.</p>
873</div>
874
875<!-------------------------------------------------------------------------- -->
876<div class="doc_subsection">
877 <a name="insert-rs-profiling-framework">Insert random sampling instrumentation framework</a>
878</div>
879<div class="doc_text">
880 <p>Yet to be written.</p>
881</div>
882
883<!-------------------------------------------------------------------------- -->
884<div class="doc_subsection">
885 <a name="instcombine">Combine redundant instructions</a>
886</div>
887<div class="doc_text">
888 <p>Yet to be written.</p>
889</div>
890
891<!-------------------------------------------------------------------------- -->
892<div class="doc_subsection">
893 <a name="internalize">Internalize Global Symbols</a>
894</div>
895<div class="doc_text">
896 <p>Yet to be written.</p>
897</div>
898
899<!-------------------------------------------------------------------------- -->
900<div class="doc_subsection">
901 <a name="ipconstprop">Interprocedural constant propagation</a>
902</div>
903<div class="doc_text">
904 <p>Yet to be written.</p>
905</div>
906
907<!-------------------------------------------------------------------------- -->
908<div class="doc_subsection">
909 <a name="ipsccp">Interprocedural Sparse Conditional Constant Propagation</a>
910</div>
911<div class="doc_text">
912 <p>Yet to be written.</p>
913</div>
914
915<!-------------------------------------------------------------------------- -->
916<div class="doc_subsection">
917 <a name="lcssa">Loop-Closed SSA Form Pass</a>
918</div>
919<div class="doc_text">
920 <p>Yet to be written.</p>
921</div>
922
923<!-------------------------------------------------------------------------- -->
924<div class="doc_subsection">
925 <a name="licm">Loop Invariant Code Motion</a>
926</div>
927<div class="doc_text">
928 <p>Yet to be written.</p>
929</div>
930
931<!-------------------------------------------------------------------------- -->
932<div class="doc_subsection">
933 <a name="loop-extract">Extract loops into new functions</a>
934</div>
935<div class="doc_text">
936 <p>Yet to be written.</p>
937</div>
938
939<!-------------------------------------------------------------------------- -->
940<div class="doc_subsection">
941 <a name="loop-extract-single">Extract at most one loop into a new function</a>
942</div>
943<div class="doc_text">
944 <p>Yet to be written.</p>
945</div>
946
947<!-------------------------------------------------------------------------- -->
948<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]949 <a name="loop-index-split">Index Split Loops</a>
950</div>
951<div class="doc_text">
952 <p>Yet to be written.</p>
953</div>
954
955<!-------------------------------------------------------------------------- -->
956<div class="doc_subsection">
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]957 <a name="loop-reduce">Loop Strength Reduction</a>
958</div>
959<div class="doc_text">
960 <p>Yet to be written.</p>
961</div>
962
963<!-------------------------------------------------------------------------- -->
964<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]965 <a name="loop-rotate">Rotate Loops</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]966</div>
967<div class="doc_text">
968 <p>Yet to be written.</p>
969</div>
970
971<!-------------------------------------------------------------------------- -->
972<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]973 <a name="loop-unroll">Unroll loops</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]974</div>
975<div class="doc_text">
976 <p>Yet to be written.</p>
977</div>
978
979<!-------------------------------------------------------------------------- -->
980<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]981 <a name="loop-unswitch">Unswitch loops</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]982</div>
983<div class="doc_text">
984 <p>Yet to be written.</p>
985</div>
986
987<!-------------------------------------------------------------------------- -->
988<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]989 <a name="loopsimplify">Canonicalize natural loops</a>
990</div>
991<div class="doc_text">
992 <p>Yet to be written.</p>
993</div>
994
995<!-------------------------------------------------------------------------- -->
996<div class="doc_subsection">
997 <a name="lower-packed">lowers packed operations to operations on smaller packed datatypes</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]998</div>
999<div class="doc_text">
1000 <p>Yet to be written.</p>
1001</div>
1002
1003<!-------------------------------------------------------------------------- -->
1004<div class="doc_subsection">
1005 <a name="lowerallocs">Lower allocations from instructions to calls</a>
1006</div>
1007<div class="doc_text">
1008 <p>Yet to be written.</p>
1009</div>
1010
1011<!-------------------------------------------------------------------------- -->
1012<div class="doc_subsection">
1013 <a name="lowergc">Lower GC intrinsics, for GCless code generators</a>
1014</div>
1015<div class="doc_text">
1016 <p>Yet to be written.</p>
1017</div>
1018
1019<!-------------------------------------------------------------------------- -->
1020<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1021 <a name="lowerinvoke">Lower invoke and unwind, for unwindless code generators</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1022</div>
1023<div class="doc_text">
1024 <p>Yet to be written.</p>
1025</div>
1026
1027<!-------------------------------------------------------------------------- -->
1028<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1029 <a name="lowerselect">Lower select instructions to branches</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1030</div>
1031<div class="doc_text">
1032 <p>Yet to be written.</p>
1033</div>
1034
1035<!-------------------------------------------------------------------------- -->
1036<div class="doc_subsection">
1037 <a name="lowersetjmp">Lower Set Jump</a>
1038</div>
1039<div class="doc_text">
1040 <p>Yet to be written.</p>
1041</div>
1042
1043<!-------------------------------------------------------------------------- -->
1044<div class="doc_subsection">
1045 <a name="lowerswitch">Lower SwitchInst's to branches</a>
1046</div>
1047<div class="doc_text">
1048 <p>Yet to be written.</p>
1049</div>
1050
1051<!-------------------------------------------------------------------------- -->
1052<div class="doc_subsection">
1053 <a name="mem2reg">Promote Memory to Register</a>
1054</div>
1055<div class="doc_text">
1056 <p>Yet to be written.</p>
1057</div>
1058
1059<!-------------------------------------------------------------------------- -->
1060<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1061 <a name="mergereturn">Unify function exit nodes</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1062</div>
1063<div class="doc_text">
1064 <p>Yet to be written.</p>
1065</div>
1066
1067<!-------------------------------------------------------------------------- -->
1068<div class="doc_subsection">
1069 <a name="predsimplify">Predicate Simplifier</a>
1070</div>
1071<div class="doc_text">
1072 <p>Yet to be written.</p>
1073</div>
1074
1075<!-------------------------------------------------------------------------- -->
1076<div class="doc_subsection">
1077 <a name="prune-eh">Remove unused exception handling info</a>
1078</div>
1079<div class="doc_text">
1080 <p>Yet to be written.</p>
1081</div>
1082
1083<!-------------------------------------------------------------------------- -->
1084<div class="doc_subsection">
1085 <a name="raiseallocs">Raise allocations from calls to instructions</a>
1086</div>
1087<div class="doc_text">
1088 <p>Yet to be written.</p>
1089</div>
1090
1091<!-------------------------------------------------------------------------- -->
1092<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1093 <a name="reassociate">Reassociate expressions</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1094</div>
1095<div class="doc_text">
1096 <p>Yet to be written.</p>
1097</div>
1098
1099<!-------------------------------------------------------------------------- -->
1100<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1101 <a name="reg2mem">Demote all values to stack slots</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1102</div>
1103<div class="doc_text">
1104 <p>Yet to be written.</p>
1105</div>
1106
1107<!-------------------------------------------------------------------------- -->
1108<div class="doc_subsection">
1109 <a name="scalarrepl">Scalar Replacement of Aggregates</a>
1110</div>
1111<div class="doc_text">
1112 <p>Yet to be written.</p>
1113</div>
1114
1115<!-------------------------------------------------------------------------- -->
1116<div class="doc_subsection">
1117 <a name="sccp">Sparse Conditional Constant Propagation</a>
1118</div>
1119<div class="doc_text">
1120 <p>Yet to be written.</p>
1121</div>
1122
1123<!-------------------------------------------------------------------------- -->
1124<div class="doc_subsection">
1125 <a name="simplify-libcalls">Simplify well-known library calls</a>
1126</div>
1127<div class="doc_text">
1128 <p>Yet to be written.</p>
1129</div>
1130
1131<!-------------------------------------------------------------------------- -->
1132<div class="doc_subsection">
1133 <a name="simplifycfg">Simplify the CFG</a>
1134</div>
1135<div class="doc_text">
1136 <p>Yet to be written.</p>
1137</div>
1138
1139<!-------------------------------------------------------------------------- -->
1140<div class="doc_subsection">
1141 <a name="strip">Strip all symbols from a module</a>
1142</div>
1143<div class="doc_text">
1144 <p>Yet to be written.</p>
1145</div>
1146
1147<!-------------------------------------------------------------------------- -->
1148<div class="doc_subsection">
1149 <a name="tailcallelim">Tail Call Elimination</a>
1150</div>
1151<div class="doc_text">
1152 <p>Yet to be written.</p>
1153</div>
1154
1155<!-------------------------------------------------------------------------- -->
1156<div class="doc_subsection">
1157 <a name="tailduplicate">Tail Duplication</a>
1158</div>
1159<div class="doc_text">
1160 <p>Yet to be written.</p>
1161</div>
1162
1163<!-- ======================================================================= -->
1164<div class="doc_section"> <a name="transform">Utility Passes</a></div>
1165<div class="doc_text">
1166 <p>This section describes the LLVM Utility Passes.</p>
1167</div>
1168
1169<!-------------------------------------------------------------------------- -->
1170<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1171 <a name="deadarghaX0r">Dead Argument Hacking (BUGPOINT USE ONLY; DO NOT USE)</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1172</div>
1173<div class="doc_text">
1174 <p>Yet to be written.</p>
1175</div>
1176
1177<!-------------------------------------------------------------------------- -->
1178<div class="doc_subsection">
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1179 <a name="extract-blocks">Extract Basic Blocks From Module (for bugpoint use)</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1180</div>
1181<div class="doc_text">
1182 <p>Yet to be written.</p>
1183</div>
1184
1185<!-------------------------------------------------------------------------- -->
1186<div class="doc_subsection">
Gabor Greif04367bf2007-07-06 22:07:22 +0000[diff] [blame]1187 <a name="emitbitcode">Bitcode Writer</a>
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1188</div>
1189<div class="doc_text">
1190 <p>Yet to be written.</p>
1191</div>
1192
1193<!-------------------------------------------------------------------------- -->
1194<div class="doc_subsection">
1195 <a name="verify">Module Verifier</a>
1196</div>
1197<div class="doc_text">
1198 <p>Yet to be written.</p>
1199</div>
1200
Gordon Henriksen1f5cce02007-10-25 08:46:12 +0000[diff] [blame]1201<!-------------------------------------------------------------------------- -->
1202<div class="doc_subsection">
1203 <a name="view-cfg">View CFG of function</a>
1204</div>
1205<div class="doc_text">
1206 <p>Yet to be written.</p>
1207</div>
1208
1209<!-------------------------------------------------------------------------- -->
1210<div class="doc_subsection">
1211 <a name="view-cfg-only">View CFG of function (with no function bodies)</a>
1212</div>
1213<div class="doc_text">
1214 <p>Yet to be written.</p>
1215</div>
1216
Reid Spencerd9aac122007-03-26 09:32:31 +0000[diff] [blame]1217<!-- *********************************************************************** -->
1218
1219<hr>
1220<address>
1221 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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1225
1226 <a href="mailto:rspencer@x10sys.com">Reid Spencer</a><br>
1227 <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
1228 Last modified: $Date$
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