We now insert accumulator variables as necessary to eliminate tail recursion
more aggressively. This is still fairly limited, but allows us to transform
fib/factorial, and other functions into nice happy loops. :)
llvm-svn: 10332
The only functionality change is that we now implement:
Regression/Transforms/TailCallElim/intervening-inst.ll
Which is really kinda pointless, because it means that trivially dead code
does not interfere with -tce, but trivially dead code probably wouldn't be
around anytime when this pass is run anyway.
The point of including this change it to support other more aggressive
transformations when we have the analysis capabilities to do so.
llvm-svn: 10312
* Make the cost metric for passing constants in as arguments to functions MUCH
more accurate, by actually estimating the amount of code that will be constant
propagated away.
llvm-svn: 10136
* Implement FuncResolve/2003-11-20-BogusResolveWarning.ll
... which eliminates a large number of annoying warnings. I know misha
will miss them though!
llvm-svn: 10123
pool allocator no end of trouble, and doesn't make a lot of sense anyway. This
does not solve the problem with mutually recursive functions, but they are much less common.
llvm-svn: 9828
Added assert() to ensure symbol table is well formed.
Added code to remember the value that was found; resolving types can change
the symbol table and invalidate the value of the iterator.
Added comments to the ResolveTypes() function (mainly for my own benefit).
Please feel free to correct the comments if they are not accurate.
llvm-svn: 9693
PHI node entries for unwind instructions just like for call instructions which
became invokes! This fixes PR57, tested by
Inline/2003-10-26-InlineInvokeExceptionDestPhi.ll
llvm-svn: 9526
as well as arguments. Now it can delete arguments and return values which are
only passed into other arguments or are returned, if they are dead. This causes
it to delete several hundred extra args/retvals from the C++ hello world program,
shrinking it by about 2K.
llvm-svn: 9398
break dominance relationships, and is otherwise bad. This fixes bug:
Inline/2003-10-13-AllocaDominanceProblem.ll. This also fixes miscompilation
of 3 176.gcc source files (reload1.c, global.c, flow.c)
llvm-svn: 9109
Only transform call sites in a setjmp'ing function which are reachable from
the setjmp. If the call dominates the setjmp (for example), the called
function cannot longjmp to the setjmp.
This dramatically reduces the number of invoke instructions created in some
large testcases.
llvm-svn: 9066
have a SINGLE backedge. This is useful to, for example, the -indvars pass.
This implements testcase LoopSimplify/single-backedge.ll and closes PR#34
llvm-svn: 9065
of a test that Bill Wendling sent me from 228.5s to 105s. Obviously there is
more improvement to be had, but this is a nice speedup which should be "felt"
by many programs.
llvm-svn: 8962
of callees between executions.
On eon, in release mode, this changes the inliner from taking 11.5712s
to taking 2.2066s. In debug mode, it went from taking 14.4148s to
taking 7.0745s. In release mode, this is a 24.7% speedup of gccas, in
debug mode, it's a total speedup of 11.7%.
This also makes it slightly more aggressive. This could be because we
are not judging the size of the functions quite as accurately as before.
When we start looking at the performance of the generated code, this can
be investigated further.
llvm-svn: 8893
Running the inliner on 252.eon used to take 48.4763s, now it takes 14.4148s.
In release mode, it went from taking 25.8741s to taking 11.5712s.
This also fixes a FIXME.
llvm-svn: 8890
"minimal" SSA form (in other words, it doesn't insert dead PHIs). This
speeds up the mem2reg pass very significantly because it doesn't have to
do a lot of frivolous work in many common cases.
In the 252.eon function I have been playing with, this doesn't even insert
the 120 PHI nodes that it used to which were trivially dead (in the process
of promoting 356 alloca instructions overall). This speeds up the mem2reg
pass from 1.2459s to 0.1284s. More significantly, the DCE pass used to take
2.4138s to remove the 120 dead PHI nodes that mem2reg constructed, now it
takes 0.0134s (which is the time to scan the function and decide that there
is nothing dead). So overall, on this one function, we speed things up a
total of 3.5179s, which is a 24.8x speedup! :)
This change is tested by the Mem2Reg/2003-10-05-DeadPHIInsertion.ll test,
which now passes.
llvm-svn: 8884
basic block. This is amazingly common in code generated by the C/C++ front-ends.
This change makes it not have to insert ANY phi nodes, whereas before it would insert
a ton of dead ones which DCE would have to clean up.
Thus, this fix improves compile-time performance of these trivial allocas in two ways:
1. It doesn't have to do the walking and book-keeping for renaming
2. It does not insert dead phi nodes for them which would have to
subsequently be cleaned up.
On my favorite testcase from 252.eon, this special case handles 305 out of
356 promoted allocas in the function. It speeds up the mem2reg pass from 7.5256s
to 1.2505s. It inserts 677 fewer dead PHI nodes, which speeds up a subsequent
-dce pass from 18.7524s to 2.4806s.
There are still 120 trivially dead PHI nodes being inserted for variables used
in multiple basic blocks, but they are not handled by this patch.
llvm-svn: 8881
*** Revamp the code which handled unreachable code in the function. Now the
code is much more efficient for high-degree basic blocks, such as those
that occur in the 252.eon SPEC benchmark.
For the interested, the time to promote a SINGLE alloca in _ZN7mrScene4ReadERSi
function used to be > 3.5s. Now it is < .075s. The function has a LOT of
allocas in it, so it appeared to be infinite looping, this should make it much
nicer. :)
llvm-svn: 8863
work-list of value definitions. This allows elimination of the explicit
'iterative' step of the algorithm, and also reuses temporary memory better.
llvm-svn: 8861
* Do not insert a new entry into NewPhiNodes during the rename pass if there are no PHIs in a block.
* Do not compute WriteSets in parallel
llvm-svn: 8858
* Eliminate the KillList instance variable, instead, just delete loads and
stores as they are "renamed", and delete allocas when they are done
* Make the 'visited' set an instance variable to avoid passing it on the stack.
llvm-svn: 8857
... by making sure to update PHI nodes to take into consideration the
extra edges we get if we inline a call instruction through an invoke.
llvm-svn: 8664
in it being both shorter and more effective. It no longer depends on the
callgraph, so one FIXME has been fixed.
Additionally, this pass was not able to delete recursive (but dead) functions
if they were pointed to by global variables which were also dead. In fact
this pass had a lot of problems deleting functions which were only pointed
to by dead globals and other stuff.
Fixing this means that the entire EH library should be stripped away now from
programs that don't use sjlj or exceptions.
llvm-svn: 8567
