running IPSCCP early, and we run functionattrs interlaced with the inliner,
we often (particularly for small or noop functions) completely propagate
all of the information about a call to its call site in IPSSCP (making a call
dead) and functionattrs is smart enough to realize that the function is
readonly (because it is interlaced with inliner).
To improve compile time and make the inliner threshold more accurate, realize
that we don't have to inline dead readonly function calls. Instead, just
delete the call. This happens all the time for C++ codes, here are some
counters from opt/llvm-ld counting the number of times calls were deleted vs
inlined on various apps:
Tramp3d opt:
5033 inline - Number of call sites deleted, not inlined
24596 inline - Number of functions inlined
llvm-ld:
667 inline - Number of functions deleted because all callers found
699 inline - Number of functions inlined
483.xalancbmk opt:
8096 inline - Number of call sites deleted, not inlined
62528 inline - Number of functions inlined
llvm-ld:
217 inline - Number of allocas merged together
2158 inline - Number of functions inlined
471.omnetpp:
331 inline - Number of call sites deleted, not inlined
8981 inline - Number of functions inlined
llvm-ld:
171 inline - Number of functions deleted because all callers found
629 inline - Number of functions inlined
Deleting a call is much faster than inlining it, and is insensitive to the
size of the callee. :)
llvm-svn: 86975
with multiple return values it inserts a PHI to merge them all together.
However, if the return values are all the same, it ends up with a pointless
PHI and this pointless PHI happens to really block SRoA from happening in
at least a silly C++ example written by Doug, but probably others. This
fixes rdar://7339069.
llvm-svn: 85206
and that will make Caller too big to inline, see if it
might be better to inline Caller into its callers instead.
This situation is described in PR 2973, although I haven't
tried the specific case in SPASS.
llvm-svn: 83602
input filename so that opt doesn't print the input filename in the
output so that grep lines in the tests don't unintentionally match
strings in the input filename.
llvm-svn: 81537
indirect function pointer, inline it, then go to delete the body.
The problem is that the callgraph had other references to the function,
though the inliner had no way to know it, so we got a dangling pointer
and an invalid iterator out of the deal.
The fix to this is pretty simple: stop the inliner from deleting the
function by knowing that there are references to it. Do this by making
CallGraphNodes contain a refcount. This requires moving deletion of
available_externally functions to the module-level cleanup sweep where
it belongs.
llvm-svn: 80533
calls into a function and if the calls bring in arrays, try to merge
them together to reduce stack size. For example, in the testcase
we'd previously end up with 4 allocas, now we end up with 2 allocas.
As described in the comments, this is not really the ideal solution
to this problem, but it is surprisingly effective. For example, on
176.gcc, we end up eliminating 67 arrays at "gccas" time and another
24 at "llvm-ld" time.
One piece of concern that I didn't look into: at -O0 -g with
forced inlining this will almost certainly result in worse debug
info. I think this is acceptable though given that this is a case
of "debugging optimized code", and we don't want debug info to
prevent the optimizer from doing things anyway.
llvm-svn: 80215
llvm.dbg.region.end instrinsic. This nested llvm.dbg.func.start/llvm.dbg.region.end pair now enables DW_TAG_inlined_subroutine support in code generator.
llvm-svn: 69118
to support C99 inline, GNU extern inline, etc. Related bugzilla's
include PR3517, PR3100, & PR2933. Nothing uses this yet, but it
appears to work.
llvm-svn: 68940
functions that don't already have a (dynamic) alloca.
Dynamic allocas cause inefficient codegen and we shouldn't
propagate this (behavior follows gcc). Two existing tests
assumed such inlining would be done; they are hacked by
adding an alloca in the caller, preserving the point of
the tests.
llvm-svn: 61946
function.
- This explicitly models the costs for functions which should
"always" or "never" be inlined. This fixes bugs where such costs
were not previously respected.
llvm-svn: 58450
