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
will get its preferred alignment. It has to be careful and cautiously assume
it will just get the ABI alignment. This prevents instcombine from rounding
up the alignment of a load/store without adjusting the alignment of the alloca.
llvm-svn: 61934
loads from allocas that cover the entire aggregate. This handles
some memcpy/byval cases that are produced by llvm-gcc. This triggers
a few times in kc++ (with std::pair<std::_Rb_tree_const_iterator
<kc::impl_abstract_phylum*>,bool>) and once in 176.gcc (with %struct..0anon).
llvm-svn: 61915
was it not very helpful, it was also wrong! The problem
is shown in the testcase: the alloca might be passed to
a nocapture callee which dereferences it and returns the
original pointer. But because it was a nocapture call we
think we don't need to track its uses, but we do.
llvm-svn: 61876
integer to a (transitive) bitcast the alloca and if that integer
has the full size of the alloca, then it clobbers the whole thing.
Handle this by extracting pieces out of the stored integer and
filing them away in the SROA'd elements.
This triggers fairly frequently because the CFE uses integers to
pass small structs by value and the inliner exposes these. For
example, in kimwitu++, I see a bunch of these with i64 stores to
"%struct.std::pair<std::_Rb_tree_const_iterator<kc::impl_abstract_phylum*>,bool>"
In 176.gcc I see a few i32 stores to "%struct..0anon".
In the testcase, this is a difference between compiling test1 to:
_test1:
subl $12, %esp
movl 20(%esp), %eax
movl %eax, 4(%esp)
movl 16(%esp), %eax
movl %eax, (%esp)
movl (%esp), %eax
addl 4(%esp), %eax
addl $12, %esp
ret
vs:
_test1:
movl 8(%esp), %eax
addl 4(%esp), %eax
ret
The second half of this will be to handle loads of the same form.
llvm-svn: 61853
In fact this also deletes those with linkonce linkage,
however this is currently dead because for the moment
aliases aren't allowed to have this linkage type.
llvm-svn: 61742
the argument to be stored to an alloca by tracking uses
of the alloca. This occurs 4 times (out of 7121, 0.05%)
in MultiSource/Applications, so may not be worth it. On
the other hand, it is easy to do and fairly cheap. The
functions it helps are: W_addcom and W_addlit in spiff;
process_args (argv) in d (make_dparser); ercPixConcealIMB
in JM/ldecod.
llvm-svn: 61570
and clean recursive descent parser.
This change has a couple of ramifications:
1. The parser code is about 400 lines shorter (in what we maintain, not
including what is autogenerated).
2. The code should be significantly faster than the old code because we
don't have to work around bison's poor handling of datatypes with
ctors/dtors. This also makes the code much more resistant to memory
leaks.
3. We now get caret diagnostics from the .ll parser, woo.
4. The actual diagnostics emited from the parser are completely different
so a bunch of testcases had to be updated.
5. I now disallow "%ty = type opaque %ty = type i32". There was no good
reason to support this, it was just an accident of the old
implementation. I have no reason to think that anyone is actually using
this.
6. The syntax for sticking a global variable has changed to make it
unambiguous. I don't think anyone is depending on this since only clang
supports this and it is not solid yet, so I'm not worried about anything
breaking.
7. This gets rid of the last use of bison, and along with it the .cvs files.
I'll prune this from the makefiles as a subsequent commit.
There are a few minor cleanups that can be done after this commit (suggestions
welcome!) but this passes dejagnu testing and is ready for its time in the
limelight.
llvm-svn: 61558
functions that don't write can't leak a pointer except through
the return value, so a void readonly function is implicitly nocapture.
Test these, and add a test that verifies that f1 calling f2 with an
otherwise dead pointer gets both of them marked nocapture.
llvm-svn: 61552
to work out (in a very simplistic way) which function
arguments (pointer arguments only) are only dereferenced
and so do not escape. Mark such arguments 'nocapture'.
llvm-svn: 61525
constants, since doing so is irrelevant for aliasing
purposes. While this doesn't increase the total number
of functions marked readonly or readnone in MultiSource/
Applications (3089), it does result in 12 functions being
marked readnone rather than readonly.
Before:
readnone: 820
readonly: 2269
After:
readnone: 832
readonly: 2257
llvm-svn: 61469
nodes. This allows it to do fairly general phi insertion if a
load from a pointer global wants to be SRAd but the load is used
by (recursive) phi nodes. This fixes a pessimization on ppc
introduced by Load PRE.
llvm-svn: 61123
consistently for deleting branches. In addition to being slightly
more readable, this makes SimplifyCFG a bit better
about cleaning up after itself when it makes conditions unused.
llvm-svn: 61100
visited set before they are used. If used, their blocks need to be
added to the visited set so that subsequent queries don't use conflicting
pointer values in the cache result blocks.
llvm-svn: 61080
cleans up the generated code a bit. This should have the added benefit of
not randomly renaming functions/globals like my previous patch did. :)
llvm-svn: 61023
memdep keeps track of how PHIs affect the pointer in dep queries, which
allows it to eliminate the load in cases like rle-phi-translate.ll, which
basically end up being:
BB1:
X = load P
br BB3
BB2:
Y = load Q
br BB3
BB3:
R = phi [P] [Q]
load R
turning "load R" into a phi of X/Y. In addition to additional exposed
opportunities, this makes memdep safe in many cases that it wasn't before
(which is required for load PRE) and also makes it substantially more
efficient. For example, consider:
bb1: // has many predecessors.
P = some_operator()
load P
In this example, previously memdep would scan all the predecessors of BB1
to see if they had something that would mustalias P. In some cases (e.g.
test/Transforms/GVN/rle-must-alias.ll) it would actually find them and end
up eliminating something. In many other cases though, it would scan and not
find anything useful. MemDep now stops at a block if the pointer is defined
in that block and cannot be phi translated to predecessors. This causes it
to miss the (rare) cases like rle-must-alias.ll, but makes it faster by not
scanning tons of stuff that is unlikely to be useful. For example, this
speeds up GVN as a whole from 3.928s to 2.448s (60%)!. IMO, scalar GVN
should be enhanced to simplify the rle-must-alias pointer base anyway, which
would allow the loads to be eliminated.
In the future, this should be enhanced to phi translate through geps and
bitcasts as well (as indicated by FIXMEs) making memdep even more powerful.
llvm-svn: 61022
llvm[2]: Linking Release executable opt (without symbols)
...
Undefined symbols:
"llvm::APFloat::IEEEsingle", referenced from:
__ZN4llvm7APFloat10IEEEsingleE$non_lazy_ptr in libLLVMCore.a(Constants.o)
__ZN4llvm7APFloat10IEEEsingleE$non_lazy_ptr in libLLVMCore.a(AsmWriter.o)
__ZN4llvm7APFloat10IEEEsingleE$non_lazy_ptr in libLLVMCore.a(ConstantFold.o)
"llvm::APFloat::IEEEdouble", referenced from:
__ZN4llvm7APFloat10IEEEdoubleE$non_lazy_ptr in libLLVMCore.a(Constants.o)
__ZN4llvm7APFloat10IEEEdoubleE$non_lazy_ptr in libLLVMCore.a(AsmWriter.o)
__ZN4llvm7APFloat10IEEEdoubleE$non_lazy_ptr in libLLVMCore.a(ConstantFold.o)
ld: symbol(s) not found
This is in release mode. To replicate, compile llvm and llvm-gcc in optimized
mode. Then build llvm, in optimized mode, with the newly created compiler.
llvm-svn: 60977
tricks based on readnone/readonly functions.
Teach memdep to look past readonly calls when analyzing
deps for a readonly call. This allows elimination of a
few more calls from 403.gcc:
before:
63 gvn - Number of instructions PRE'd
153986 gvn - Number of instructions deleted
50069 gvn - Number of loads deleted
after:
63 gvn - Number of instructions PRE'd
153991 gvn - Number of instructions deleted
50069 gvn - Number of loads deleted
5 calls isn't much, but this adds plumbing for the next change.
llvm-svn: 60794
doesn't do its own local caching, and is slightly more aggressive about
free/store dse (see testcase). This eliminates the last external client
of MemDep::getDependenceFrom().
llvm-svn: 60619
This fixes many bugs. I will add more test cases in a separate check-in.
Some day, the code that manipulates CFG and updates dom. info could use refactoring help.
llvm-svn: 60554
1) have it fold "br undef", which does occur with
surprising frequency as jump threading iterates.
2) teach j-t to delete dead blocks. This removes the successor
edges, reducing the in-edges of other blocks, allowing
recursive simplification.
3) Fold things like:
br COND, BBX, BBY
BBX:
br COND, BBZ, BBW
which also happens because jump threading iterates.
llvm-svn: 60470
straight-forward implementation. This does not require any extra
alias analysis queries beyond what we already do for non-local loads.
Some programs really really like load PRE. For example, SPASS triggers
this ~1000 times, ~300 times in 255.vortex, and ~1500 times on 403.gcc.
The biggest limitation to the implementation is that it does not split
critical edges. This is a huge killer on many programs and should be
addressed after the initial patch is enabled by default.
The implementation of this should incidentally speed up rejection of
non-local loads because it avoids creating the repl densemap in cases
when it won't be used for fully redundant loads.
This is currently disabled by default.
Before I turn this on, I need to fix a couple of miscompilations in
the testsuite, look at compile time performance numbers, and look at
perf impact. This is pretty close to ready though.
llvm-svn: 60408
overflowed on negation. This commit checks to make sure that neithe C nor X
overflows. This requires that the RHS of X (a subtract instruction) be a
constant integer.
llvm-svn: 60275
properly updates the reverse dependency map when it installs updated
dependencies for instructions that depend on the removed instruction.
llvm-svn: 60222
1. Make it fold blocks separated by an unconditional branch. This enables
jump threading to see a broader scope.
2. Make jump threading able to eliminate locally redundant loads when they
feed the branch condition of a block. This frequently occurs due to
reg2mem running.
3. Make jump threading able to eliminate *partially redundant* loads when
they feed the branch condition of a block. This is common in code with
lots of loads and stores like C++ code and 255.vortex.
This implements thread-loads.ll and rdar://6402033.
Per the fixme's, several pieces of this should be moved into Transforms/Utils.
llvm-svn: 60148
to generate signed ICMP instructions to replace the FCMP. This would violate
the following:
define i1 @test1(i32 %val) {
%1 = uitofp i32 %val to double
%2 = fcmp ole double %1, 0.000000e+00
ret i1 %2
}
would be transformed into:
define i1 @test1(i32 %val) {
%1 = icmp slt i33 %val, 1
ret i1 %1
}
which is obviously wrong. This patch modifes InstCombiner::FoldFCmp_IntToFP_Cst
to handle when the LHS comes from UIToFP.
llvm-svn: 58929
This allows SCEV users to effectively calculate trip count.
LSR later on transforms back integer IVs to floating point IVs
later on to avoid int-to-float casts inside the loop.
llvm-svn: 58625
* merge two weak functions by making them both alias a third non-weak fn
* don't reimplement CallSite::hasArgument
* whitelist the safe linkage types
llvm-svn: 58568
This triggers only 60 times in llvm-test (look at .llvm.bc, not .linked.rbc)
and so it probably wont be turned on by default. Also, may of those are likely
to go away when PR2973 is fixed.
llvm-svn: 58557
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
to find opportunities for store-to-load forwarding or load CSE,
in the same way that visitStore scans back to do DSE. Also, define
a new helper function for testing whether the addresses of two
memory accesses are known to have the same value, and use it in
both visitStore and visitLoad.
These two changes allow instcombine to eliminate loads in code
produced by front-ends that frequently emit obviously redundant
addressing for memory references.
llvm-svn: 57608
This includes not marking a GEP involving a vector as unsafe, but only when it
has all zero indices. This allows scalarrepl to work in a few more cases.
llvm-svn: 57177
shifting and masking inside a bswap expr. This allows it to handle
the cases from PR2842, which involve the intermediate 'or'
expressions being shifted, not just the input value.
llvm-svn: 57095
when deciding whether to mark a function readnone/readonly.
Since the pass is currently run before SROA, this may be
quite helpful. Requested by Chris on IRC.
llvm-svn: 57050
I originally made this script to show that scalarrepl didn't support them, but
it turned out it does. Better to still add the testcase then.
llvm-svn: 56781
can get the readnone/readonly attributes, and gives them it.
The plan is to remove markmodref (which did the same thing
by querying GlobalsModRef) and delete the analogous
functionality from GlobalsModRef.
llvm-svn: 56341
- Recognize expressions like "x > -1 ? x : 0" as min/max and turn them
into expressions like "x < 0 ? 0 : x", which is easily recognizable
as a min/max operation.
- Refrain from folding expression like "y/2 < 1" to "y < 2" when the
comparison is being used as part of a min or max idiom, like
"y/2 < 1 ? 1 : y/2". In that case, the division has another use, so
folding doesn't eliminate it, and obfuscates the min/max, making it
harder to recognize as a min/max operation.
These benefit ScalarEvolution, CodeGen, and anything else that wants to
recognize integer min and max.
llvm-svn: 56246
users, and teach it about shufflevector instructions.
Also, fix a subtle bug in SimplifyDemandedVectorElts'
insertelement code.
This is a patch that was originally written by Eli Friedman,
with some fixes and cleanup by me.
llvm-svn: 55995
call (thus changing the call site) it didn't
inform the callgraph about this. But the
call site does matter - as shown by the testcase,
the callgraph become invalid after the inliner
ran (with an edge between two functions simply
missing), resulting in wrong deductions by
GlobalsModRef.
llvm-svn: 55872
be folded. Instead, fail to fold the entire vector.
We could also return a vector with some elements folded and some not. If anyone
thinks that's a better approach, please speak up!
llvm-svn: 55689
do for scalars. Patch contributed by Nicolas Capens
This also generalizes the previous xforms to work on long double, now that
isExactlyValue works for long double.
llvm-svn: 54653
that says "unconditional loads from this argument are safe", we now keep track
of the safety per set of indices from which loads happen. This prevents
ArgPromotion from promoting loads that aren't really valid. As an added effect,
this will now disregard the the type of the indices passed to a GEP, so
"load GEP %A, i32 1" and "load GEP %A, i64 1" will result in a single argument,
not two.
This fixes PR2598, for which a testcase has been added as well.
llvm-svn: 54159
command-line option, and disable it by default. It introduced performance
regressions because CodeGen is currently not able to remat such loads.
llvm-svn: 53997
case for this.
This allows instructions like loads from global variables declared to
be constant to be moved out of loops."
Patch by Stefanus Du Toit!
llvm-svn: 53945
Remove the GetResultInst instruction. It is still accepted in LLVM assembly
and bitcode, where it is now auto-upgraded to ExtractValueInst. Also, remove
support for return instructions with multiple values. These are auto-upgraded
to use InsertValueInst instructions.
The IRBuilder still accepts multiple-value returns, and auto-upgrades them
to InsertValueInst instructions.
llvm-svn: 53941
leads into a cycle involving a different PHI, LSR got stuck running
around that cycle looking for the original PHI. To avoid this, keep
track of visited PHIs and stop searching if we see one more than once.
This fixes PR2570.
llvm-svn: 53879
return values that are still (partially) live. Instead of updating all uses of
a call instruction after removing some elements, it now just rebuilds the
original struct (With undef gaps where the unused values were) and leaves it to
instcombine to clean this up.
The added testcase still fails currently, but this is due to instcombine which
isn't good enough yet. I will fix that part next.
llvm-svn: 53608
was using the algorithm for folding unsigned comparisons which is
completely wrong. This has been broken since the signless types change.
llvm-svn: 53444
This cause a regression in InstCombine/JavaCompare, which was doing the right
thing on accident. To handle the missed case, generalize the comparisons based
on masked bits a little bit to handle comparisons against the max value. For
example, we can now xform (slt i32 (and X, 4), 4) -> (setne i32 (and X, 4), 4)
llvm-svn: 53443
Rewrite the DeadArgumentElimination pass, to use a more explicit tracking of
dependencies between return values and/or arguments. Also make the handling of
arguments and return values the same.
The pass now looks properly inside returned structs, but only at the first
level (ie, not inside nested structs).
This version fixed a few more bugs and was cleaned up a bit. It now passes all
of LLVM's testing, and should still pass SPEC2006. There is still a minor bug
with regard to returning nested structs. Since there is currently nothing that
emits such IR, I will fix that in a seperate commit (partly because it requires
a non-trivial fix).
llvm-svn: 53400
