Weights that estimate_num_insns uses to estimate the size of the
produced code.
@verbatim
Tree inlining. Copyright (C) 2001-2013 Free Software Foundation, Inc. Contributed by Alexandre Oliva aoliv.nosp@m.a@re.nosp@m.dhat..nosp@m.com
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I'm not real happy about this, but we need to handle gimple and
non-gimple trees.
Inlining, Cloning, Versioning, Parallelization
Inlining: a function body is duplicated, but the PARM_DECLs are
remapped into VAR_DECLs, and non-void RETURN_EXPRs become
MODIFY_EXPRs that store to a dedicated returned-value variable.
The duplicated eh_region info of the copy will later be appended
to the info for the caller; the eh_region info in copied throwing
statements and RESX statements are adjusted accordingly.
Cloning: (only in C++) We have one body for a con/de/structor, and
multiple function decls, each with a unique parameter list.
Duplicate the body, using the given splay tree; some parameters
will become constants (like 0 or 1).
Versioning: a function body is duplicated and the result is a new
function rather than into blocks of an existing function as with
inlining. Some parameters will become constants.
Parallelization: a region of a function is duplicated resulting in
a new function. Variables may be replaced with complex expressions
to enable shared variable semantics.
All of these will simultaneously lookup any callgraph edges. If
we're going to inline the duplicated function body, and the given
function has some cloned callgraph nodes (one for each place this
function will be inlined) those callgraph edges will be duplicated.
If we're cloning the body, those callgraph edges will be
updated to point into the new body. (Note that the original
callgraph node and edge list will not be altered.)
See the CALL_EXPR handling case in copy_tree_body_r ().
To Do:
o In order to make inlining-on-trees work, we pessimized
function-local static constants. In particular, they are now
always output, even when not addressed. Fix this by treating
function-local static constants just like global static
constants; the back-end already knows not to output them if they
are not needed.
o Provide heuristics to clamp inlining of recursive template
calls?
Weights that estimate_num_insns uses to estimate the size of the
produced code.
Referenced by count_insns(), and tree_ssa_unswitch_loops().