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author | amacleod <amacleod@138bc75d-0d04-0410-961f-82ee72b054a4> | 2005-04-15 16:29:34 +0000 |
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committer | amacleod <amacleod@138bc75d-0d04-0410-961f-82ee72b054a4> | 2005-04-15 16:29:34 +0000 |
commit | 891a3b72b2ee920b913a502ca0b70a24671679dc (patch) | |
tree | 9bd608be33b9dbc9bb112884069a1c08035d5939 /gcc/doc/tree-ssa.texi | |
parent | a6e94e944f94a5f7c4dfca9425fd2df67c76d8cc (diff) | |
download | gcc-891a3b72b2ee920b913a502ca0b70a24671679dc.tar.gz |
2005-04-15 Andrew Macleod <amacleod@redhat.com>
* doc/tree-ssa.texi: Grammer/abbreviation updates.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@98190 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/doc/tree-ssa.texi')
-rw-r--r-- | gcc/doc/tree-ssa.texi | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/gcc/doc/tree-ssa.texi b/gcc/doc/tree-ssa.texi index d1c3c1ffcec..2665b839a86 100644 --- a/gcc/doc/tree-ssa.texi +++ b/gcc/doc/tree-ssa.texi @@ -886,13 +886,13 @@ print_ops (tree stmt) @} @end smallexample -Operands use to be updated lazily via calls to @code{get_stmt_operands}. -This function is now deprecated and operands are updated as soon as the stmt is -finished via a call to @code{update_stmt}. If statement elements are -changed via @code{SET_USE} or @code{SET_DEF}, no further action need be -taken (ie, those macros take care of whatever updating is required). If -changes are made by manipulating the statement's tree directly, then a call -must be made to @code{update_stmt} when complete. Calling one of the +Operands were once updated lazily via calls to @code{get_stmt_operands}. +This function is now deprecated and operands are updated as soon as the +statement is finished via a call to @code{update_stmt}. If statement elements +are changed via @code{SET_USE} or @code{SET_DEF}, then no further action is +required (ie, those macros take care of updating the statement). If +changes are made by manipulating the statement's tree directly, then a call +must be made to @code{update_stmt} when complete. Calling one of the @code{bsi_insert} routines or @code{bsi_replace} performs an implicit call to @code{update_stmt}. @@ -1033,6 +1033,10 @@ iterators, you may examine every use of any @code{SSA_NAME}. For instance, to change each use of @code{ssa_var} to @code{ssa_var2}: @smallexample + use_operand_p imm_use_p; + imm_use_iterator iterator; + tree ssa_var + FOR_EACH_IMM_USE_SAFE (imm_use_p, iterator, ssa_var) SET_USE (imm_use_p, ssa_var_2); @end smallexample @@ -1073,27 +1077,30 @@ Some useful functions and macros: single use of @code{ssa_var}. @item @code{single_imm_use (ssa_var, use_operand_p *ptr, tree *stmt)} : Returns true if there is only a single use of @code{ssa_var}, and also returns -the use pointer and stmt it occurs in in the second and third parameters. +the use pointer and statement it occurs in in the second and third parameters. @item @code{num_imm_uses (ssa_var)} : Returns the number of immediate uses of -@code{ssa_var}. Its better not to use this if possible since it simply +@code{ssa_var}. It is better not to use this if possible since it simply utilizes a loop to count the uses. @item @code{PHI_ARG_INDEX_FROM_USE (use_p)} : Given a use within a @code{PHI} node, return the index number for the use. An assert is triggered if the use isn't located in a @code{PHI} node. -@item @code{USE_STMT (use_p)} : Return the stmt a use occurs in. +@item @code{USE_STMT (use_p)} : Return the statement a use occurs in. @end enumerate Note that uses are not put into an immediate use list until their statement is actually inserted into the instruction stream via a @code{bsi_*} routine. -It is also still possible to utilize lazy updating of stmts, but this should be used only when absolutely required. Both alias analysis and the dominator -optimizations currently do this. +It is also still possible to utilize lazy updating of statements, but this +should be used only when absolutely required. Both alias analysis and the +dominator optimizations currently do this. When lazy updating is being used, the immediate use information is out of date -and cannot be used reliably. Lazy updating is achieved by simply marking stmts -modified via calls to @code{mark_stmt_modified} instead of @code{update_stmt}. -When lazy updating is no longer required, all the modified stmts must have -@code{update_stmt} called in order to bring them up to date. This must be done before the optimization is finished, or @code{verify_ssa} will trigger an abort. +and cannot be used reliably. Lazy updating is achieved by simply marking +statements modified via calls to @code{mark_stmt_modified} instead of +@code{update_stmt}. When lazy updating is no longer required, all the +modified statements must have @code{update_stmt} called in order to bring them +up to date. This must be done before the optimization is finished, or +@code{verify_ssa} will trigger an abort. This is done with a simple loop over the instruction stream: @smallexample |