Currently in JumpThreading pass, the branch weight metadata is not updated after CFG modification. Consider the jump threading on PredBB, BB, and SuccBB. After jump threading, the weight on BB->SuccBB should be adjusted as some of it is contributed by the edge PredBB->BB, which doesn't exist anymore. This patch tries to update the edge weight in metadata on BB->SuccBB by scaling it by 1 - Freq(PredBB->BB) / Freq(BB->SuccBB).
This is the third attempt to submit this patch, while the first two led to failures in some FDO tests. After investigation, it is the edge weight normalization that caused those failures. In this patch the edge weight normalization is fixed so that there is no zero weight in the output and the sum of all weights can fit in 32-bit integer. Several unit tests are added.
Differential revision: http://reviews.llvm.org/D10979
llvm-svn: 250345
If we have a series of branches which are all unlikely to fail, we can possibly combine them into a single check on the fastpath combined with a bit of dispatch logic on the slowpath. We don't want to do this unconditionally since it requires speculating instructions past a branch, but if the profiling metadata on the branch indicates profitability, this can reduce the number of checks needed along the fast path.
The canonical example this is trying to handle is removing the second bounds check implied by the Java code: a[i] + a[i+1]. Note that it can currently only do so for really simple conditions and the values of a[i] can't be used anywhere except in the addition. (i.e. the load has to have been sunk already and not prevent speculation.) I plan on extending this transform over the next few days to handle alternate sequences.
Differential Revision: http://reviews.llvm.org/D13070
llvm-svn: 250343
Some background on why we don't have to use *coal* sections anymore:
Long ago when C++ was new and "weak" had not been standardized, an attempt was
made in cctools to support C++ inlines that can be coalesced by putting them
into their own section (TEXT/textcoal_nt instead of TEXT/text).
The current macho linker supports the weak-def bit on any symbol to allow it to
be coalesced, but the compiler still puts weak-def functions/data into alternate
section names, which the linker must map back to the base section name.
This patch makes changes that are necessary to prevent the compiler from using
the "coal" sections and have it use the non-coal sections instead when the
target architecture is not powerpc:
TEXT/textcoal_nt instead use TEXT/text
TEXT/const_coal instead use TEXT/const
DATA/datacoal_nt instead use DATA/data
If the target is powerpc, we continue to use the *coal* sections since anyone
targeting powerpc is probably using an old linker that doesn't have support for
the weak-def bits.
Also, have the assembler issue a warning if it encounters a *coal* section in
the assembly file and inform the users to use the non-coal sections instead.
rdar://problem/14265330
Differential Revision: http://reviews.llvm.org/D13188
llvm-svn: 250342
This is a cleaned up patch from the one written by John Regehr based on the findings of the Souper superoptimizer.
The basic idea here is that input bits that are known zero reduce the maximum count that the intrinsic could return. We know that the number of bits required to represent a particular count is at most log2(N)+1.
Differential Revision: http://reviews.llvm.org/D13253
llvm-svn: 250338
PR25157 identifies a bug where a load plus a vector shuffle is
incorrectly converted into an LXVDSX instruction. That optimization
is only valid if the load is of a doubleword, and in the noted case,
it was not. This corrects that problem.
Joint patch with Eric Schweitz, who provided the bugpoint-reduced test
case.
llvm-svn: 250324
This adds documentation for the binary profile encoding and moves the
documentation for the text encoding into the header file
SampleProfReader.h.
llvm-svn: 250309
Summary:
Caching SDLoc(N), instead of recreating it in every single
function call, keeps the code denser, and allows to unwrap long lines.
Reviewers: sunfish, atrick, sdmitrouk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13726
llvm-svn: 250305
Summary: The two implementations had more code in common than not.
Reviewers: sunfish, MatzeB, sdmitrouk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13724
llvm-svn: 250302
This patch teaches x86 fast-isel how to select nontemporal stores.
On x86, we can use MOVNTI for nontemporal stores of doublewords/quadwords.
Instructions (V)MOVNTPS/PD/DQ can be used for SSE2/AVX aligned nontemporal
vector stores.
Before this patch, fast-isel always selected 'movd/movq' instead of 'movnti'
for doubleword/quadword nontemporal stores. In the case of nontemporal stores
of aligned vectors, fast-isel always selected movaps/movapd/movdqa instead of
movntps/movntpd/movntdq.
With this patch, if we use SSE2/AVX intrinsics for nontemporal stores we now
always get the expected (V)MOVNT instructions.
The lack of fast-isel support for nontemporal stores was spotted when analyzing
the -O0 codegen for nontemporal stores.
Differential Revision: http://reviews.llvm.org/D13698
llvm-svn: 250285
Binary encoded profiles used to encode all function names inline at
every reference. This is clearly suboptimal in terms of space. This
patch fixes this by adding a name table to the header of the file.
llvm-svn: 250241
We forgot to append the terminatepad's arguments which resulted in us
treating the old terminatepad as an argument to the new terminatepad
causing us to crash immediately. Instead, add the old terminatepad's
arguments to the new terminatepad.
This fixes PR25155.
llvm-svn: 250234
ArchiveMemberHeader, suggestion by Rafael Espíndola.
Also The clang-x86-win2008-selfhost bot still does not like the
malformed-machos 00000031.a test, so removing it for now. All
the other bots are fine with it however.
llvm-svn: 250222
Summary:
Emit the handler and clause locations immediately after the standard
xdata.
Clauses are emitted in the same order and format used to communiate them
to the CLR Execution Engine.
Add a lit test to verify correct table generation on a small but
interesting example function.
Reviewers: majnemer, andrew.w.kaylor, rnk
Subscribers: pgavlin, AndyAyers, llvm-commits
Differential Revision: http://reviews.llvm.org/D13451
llvm-svn: 250219
One of the changes in lib/Target/AMDGPU/AMDGPUMCInstLower.cpp was a new
one. Previously, bundle iterators and single-instruction iterators
could be compared to each other (comparing on underlying pointers).
I changed a comparison from using `MBB->end()` to using
`MBB->instr_end()`, since both end iterators should point at the some
place anyway.
I don't think the implicit conversion between the two iterator types is
a good idea since it's fairly easy to accidentally compare to the wrong
thing (they aren't always end iterators). Otherwise I would have just
added the conversion.
Even with that, no there should be functionality change here.
llvm-svn: 250218
Remove remaining `ilist_iterator` implicit conversions from
LLVMScalarOpts.
This change exposed some scary behaviour in
lib/Transforms/Scalar/SCCP.cpp around line 1770. This patch changes a
call from `Function::begin()` to `&Function::front()`, since the return
was immediately being passed into another function that takes a
`Function*`. `Function::front()` started to assert, since the function
was empty. Note that `Function::end()` does not point at a legal
`Function*` -- it points at an `ilist_half_node` -- so the other
function was getting garbage before. (I added the missing check for
`Function::isDeclaration()`.)
Otherwise, no functionality change intended.
llvm-svn: 250211
Currently in JumpThreading pass, the branch weight metadata is not updated after CFG modification. Consider the jump threading on PredBB, BB, and SuccBB. After jump threading, the weight on BB->SuccBB should be adjusted as some of it is contributed by the edge PredBB->BB, which doesn't exist anymore. This patch tries to update the edge weight in metadata on BB->SuccBB by scaling it by 1 - Freq(PredBB->BB) / Freq(BB->SuccBB).
Differential revision: http://reviews.llvm.org/D10979
llvm-svn: 250204
On Linux, the profile runtime can use __start_SECTNAME and __stop_SECTNAME
symbols defined by the linker to locate the start and end location of
a named section (with C name). This eliminates the need for instrumented
binary to call __llvm_profile_register_function during start-up time.
llvm-svn: 250199
Summary:
Add an iterator that can walk across blocks and which visits the state
transitions rather than state ranges, with explicit transitions to -1
indicating the presence of top-level calls that may throw and cause the
current function to unwind to caller. This will simplify code that needs
to identify nested try regions.
Refactor SEH and C++EH table generation to use the new
InvokeStateChangeIterator, and remove the InvokeLabelIterator they were
using.
Reviewers: majnemer, andrew.w.kaylor, rnk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13623
llvm-svn: 250179
As discussed in D13348 - the INSERTQI range combining code is wrong in that it confuses the insertion bit index with an extraction bit index.
The remaining legal combines are very unlikely (especially once we've converted to shuffles in D13348) so I'm removing the optimization.
llvm-svn: 250160
Now that all the known faults with GlobalsAA have been fixed, flip the big switch on -enable-non-lto-gmr again.
Feel free to pester me with any more bugs found, and don't hesitate to flip the switch back off.
llvm-svn: 250157
Weak linkage and friends allow a symbol to be overriden outside the
code generator's model, so GlobalsAA shouldn't assume that anything it
can compute about such a symbol is valid.
llvm-svn: 250156
