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Diffstat (limited to 'docs/Passes.html')
-rw-r--r-- | docs/Passes.html | 113 |
1 files changed, 2 insertions, 111 deletions
diff --git a/docs/Passes.html b/docs/Passes.html index 362be32d7d..8c408f4535 100644 --- a/docs/Passes.html +++ b/docs/Passes.html @@ -78,7 +78,6 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! <tr><td><a href="#anders-aa">-anders-aa</a></td><td>Andersen's Interprocedural Alias Analysis</td></tr> <tr><td><a href="#basicaa">-basicaa</a></td><td>Basic Alias Analysis (default AA impl)</td></tr> <tr><td><a href="#basiccg">-basiccg</a></td><td>Basic CallGraph Construction</td></tr> -<tr><td><a href="#basicvn">-basicvn</a></td><td>Basic Value Numbering (default GVN impl)</td></tr> <tr><td><a href="#codegenprepare">-codegenprepare</a></td><td>Optimize for code generation</td></tr> <tr><td><a href="#count-aa">-count-aa</a></td><td>Count Alias Analysis Query Responses</td></tr> <tr><td><a href="#debug-aa">-debug-aa</a></td><td>AA use debugger</td></tr> @@ -90,7 +89,6 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! <tr><td><a href="#globalsmodref-aa">-globalsmodref-aa</a></td><td>Simple mod/ref analysis for globals</td></tr> <tr><td><a href="#instcount">-instcount</a></td><td>Counts the various types of Instructions</td></tr> <tr><td><a href="#intervals">-intervals</a></td><td>Interval Partition Construction</td></tr> -<tr><td><a href="#load-vn">-load-vn</a></td><td>Load Value Numbering</td></tr> <tr><td><a href="#loops">-loops</a></td><td>Natural Loop Construction</td></tr> <tr><td><a href="#memdep">-memdep</a></td><td>Memory Dependence Analysis</td></tr> <tr><td><a href="#no-aa">-no-aa</a></td><td>No Alias Analysis (always returns 'may' alias)</td></tr> @@ -125,11 +123,9 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! <tr><td><a href="#deadtypeelim">-deadtypeelim</a></td><td>Dead Type Elimination</td></tr> <tr><td><a href="#die">-die</a></td><td>Dead Instruction Elimination</td></tr> <tr><td><a href="#dse">-dse</a></td><td>Dead Store Elimination</td></tr> -<tr><td><a href="#gcse">-gcse</a></td><td>Global Common Subexpression Elimination</td></tr> <tr><td><a href="#globaldce">-globaldce</a></td><td>Dead Global Elimination</td></tr> <tr><td><a href="#globalopt">-globalopt</a></td><td>Global Variable Optimizer</td></tr> <tr><td><a href="#gvn">-gvn</a></td><td>Global Value Numbering</td></tr> -<tr><td><a href="#gvnpre">-gvnpre</a></td><td>Global Value Numbering/Partial Redundancy Elimination</td></tr> <tr><td><a href="#indmemrem">-indmemrem</a></td><td>Indirect Malloc and Free Removal</td></tr> <tr><td><a href="#indvars">-indvars</a></td><td>Canonicalize Induction Variables</td></tr> <tr><td><a href="#inline">-inline</a></td><td>Function Integration/Inlining</td></tr> @@ -161,7 +157,6 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! <tr><td><a href="#mem2reg">-mem2reg</a></td><td>Promote Memory to Register</td></tr> <tr><td><a href="#memcpyopt">-memcpyopt</a></td><td>Optimize use of memcpy and friends</td></tr> <tr><td><a href="#mergereturn">-mergereturn</a></td><td>Unify function exit nodes</td></tr> -<tr><td><a href="#predsimplify">-predsimplify</a></td><td>Predicate Simplifier</td></tr> <tr><td><a href="#prune-eh">-prune-eh</a></td><td>Remove unused exception handling info</td></tr> <tr><td><a href="#raiseallocs">-raiseallocs</a></td><td>Raise allocations from calls to instructions</td></tr> <tr><td><a href="#reassociate">-reassociate</a></td><td>Reassociate expressions</td></tr> @@ -304,25 +299,6 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! <!-------------------------------------------------------------------------- --> <div class="doc_subsection"> - <a name="basicvn">Basic Value Numbering (default Value Numbering impl)</a> -</div> -<div class="doc_text"> - <p> - This is the default implementation of the <code>ValueNumbering</code> - interface. It walks the SSA def-use chains to trivially identify - lexically identical expressions. This does not require any ahead of time - analysis, so it is a very fast default implementation. - </p> - <p> - The ValueNumbering analysis passes are mostly deprecated. They are only used - by the <a href="#gcse">Global Common Subexpression Elimination pass</a>, which - is deprecated by the <a href="#gvn">Global Value Numbering pass</a> (which - does its value numbering on its own). - </p> -</div> - -<!-------------------------------------------------------------------------- --> -<div class="doc_subsection"> <a name="codegenprepare">Optimize for code generation</a> </div> <div class="doc_text"> @@ -461,28 +437,6 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! <!-------------------------------------------------------------------------- --> <div class="doc_subsection"> - <a name="load-vn">Load Value Numbering</a> -</div> -<div class="doc_text"> - <p> - This pass value numbers load and call instructions. To do this, it finds - lexically identical load instructions, and uses alias analysis to determine - which loads are guaranteed to produce the same value. To value number call - instructions, it looks for calls to functions that do not write to memory - which do not have intervening instructions that clobber the memory that is - read from. - </p> - - <p> - This pass builds off of another value numbering pass to implement value - numbering for non-load and non-call instructions. It uses Alias Analysis so - that it can disambiguate the load instructions. The more powerful these base - analyses are, the more powerful the resultant value numbering will be. - </p> -</div> - -<!-------------------------------------------------------------------------- --> -<div class="doc_subsection"> <a name="loops">Natural Loop Construction</a> </div> <div class="doc_text"> @@ -865,23 +819,6 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! <!-------------------------------------------------------------------------- --> <div class="doc_subsection"> - <a name="gcse">Global Common Subexpression Elimination</a> -</div> -<div class="doc_text"> - <p> - This pass is designed to be a very quick global transformation that - eliminates global common subexpressions from a function. It does this by - using an existing value numbering analysis pass to identify the common - subexpressions, eliminating them when possible. - </p> - <p> - This pass is deprecated by the <a href="#gvn">Global Value Numbering pass</a> - (which does a better job with its own value numbering). - </p> -</div> - -<!-------------------------------------------------------------------------- --> -<div class="doc_subsection"> <a name="globaldce">Dead Global Elimination</a> </div> <div class="doc_text"> @@ -912,35 +849,11 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if ! </div> <div class="doc_text"> <p> - This pass performs global value numbering to eliminate fully redundant - instructions. It also performs simple dead load elimination. - </p> - <p> - Note that this pass does the value numbering itself, it does not use the - ValueNumbering analysis passes. + This pass performs global value numbering to eliminate fully and partially + redundant instructions. It also performs redundant load elimination. </p> </div> -<!-------------------------------------------------------------------------- --> -<div class="doc_subsection"> - <a name="gvnpre">Global Value Numbering/Partial Redundancy Elimination</a> -</div> -<div class="doc_text"> - <p> - This pass performs a hybrid of global value numbering and partial redundancy - elimination, known as GVN-PRE. It performs partial redundancy elimination on - values, rather than lexical expressions, allowing a more comprehensive view - the optimization. It replaces redundant values with uses of earlier - occurences of the same value. While this is beneficial in that it eliminates - unneeded computation, it also increases register pressure by creating large - live ranges, and should be used with caution on platforms that are very - sensitive to register pressure. - </p> - <p> - Note that this pass does the value numbering itself, it does not use the - ValueNumbering analysis passes. - </p> -</div> <!-------------------------------------------------------------------------- --> <div class="doc_subsection"> @@ -1578,28 +1491,6 @@ if (X < 3) {</pre> <!-------------------------------------------------------------------------- --> <div class="doc_subsection"> - <a name="predsimplify">Predicate Simplifier</a> -</div> -<div class="doc_text"> - <p> - Path-sensitive optimizer. In a branch where <tt>x == y</tt>, replace uses of - <tt>x</tt> with <tt>y</tt>. Permits further optimization, such as the - elimination of the unreachable call: - </p> - -<blockquote><pre ->void test(int *p, int *q) -{ - if (p != q) - return; - - if (*p != *q) - foo(); // unreachable -}</pre></blockquote> -</div> - -<!-------------------------------------------------------------------------- --> -<div class="doc_subsection"> <a name="prune-eh">Remove unused exception handling info</a> </div> <div class="doc_text"> |