The way that stack coloring updated MMOs when merging stack slots, while
correct, is suboptimal, and is incompatible with the use of AA during
instruction scheduling. The solution, which involves the use of const_cast (and
more importantly, updating the IR from within an MI-level pass), obviously
requires some explanation:
When the stack coloring pass was originally committed, the code in
ScheduleDAGInstrs::buildSchedGraph tracked possible alias sets by using
GetUnderlyingObject, and all load/store and store/store memory control
dependencies where added between SUs at the object level (where only one
object, that returned by GetUnderlyingObject, was used to identify the object
associated with each MMO). When stack coloring merged stack slots, it would
replace MMOs derived from the remapped alloca with the alloca with which the
remapped alloca was being replaced. Because ScheduleDAGInstrs only used single
objects, and tracked alias sets at the object level, this was a fine solution.
In r169744, (Andy and) I updated the code in ScheduleDAGInstrs to use
GetUnderlyingObjects, and track alias sets using, potentially, multiple
underlying objects for each MMO. This was done, primarily, to provide the
ability to look through PHIs, and provide better scheduling for
induction-variable-dependent loads and stores inside loops. At this point, the
MMO-updating code in stack coloring became suboptimal, because it would clear
the MMOs for (i.e. completely pessimize) all instructions for which r169744
might help in scheduling. Updating the IR directly is the simplest fix for this
(and the one with, by far, the least compile-time impact), but others are
possible (we could give each MMO a small vector of potential values, or make
use of a remapping table, constructed from MFI, inside ScheduleDAGInstrs).
Unfortunately, replacing all MMO values derived from the remapped alloca with
the base replacement alloca fundamentally breaks our ability to use AA during
instruction scheduling (which is critical to performance on some targets). The
reason is that the original MMO might have had an offset (either constant or
dynamic) from the base remapped alloca, and that offset is not present in the
updated MMO. One possible way around this would be to use
GetPointerBaseWithConstantOffset, and update not only the MMO's value, but also
its offset based on the original offset. Unfortunately, this solution would
only handle constant offsets, and for safety (because AA is not completely
restricted to deducing relationships with constant offsets), we would need to
clear all MMOs without constant offsets over the entire function. This would be
an even worse pessimization than the current single-object restriction. Any
other solution would involve passing around a vector of remapped allocas, and
teaching AA to use it, introducing additional complexity and overhead into AA.
Instead, when remapping an alloca, we replace all IR uses of that alloca as
well (optionally inserting a bitcast as necessary). This is even more efficient
that the old MMO-updating code in the stack coloring pass (because it removes
the need to call GetUnderlyingObject on all MMO values), removes the
single-object pessimization in the default configuration, and enables the
correct use of AA during instruction scheduling (all without any additional
overhead).
LLVM now no longer miscompiles itself on x86_64 when using -enable-misched
-enable-aa-sched-mi -misched-bottomup=0 -misched-topdown=0 -misched=shuffle!
Fixed PR18497.
Because the alloca replacement is now done at the IR level, unless the MMO
directly refers to the remapped alloca, the change cannot be seen at the MI
level. As a result, there is no good way to fix test/CodeGen/X86/pr14090.ll.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199658 91177308-0d34-0410-b5e6-96231b3b80d8
When using AA to break false chain dependencies, we need to track multiple
stores per object in ScheduleDAGInstrs. Historically, we tracked potential alias
chains at the object level, and so all loads of an object would retain
dependencies on any store to that object. With AA, however, this is not
sufficient: non-overlapping stores and loads to the same object all need to be
tested for dependencies separately, we cannot only test all loads to an object
against only the last store (see PR18497 for an explicit example).
To mitigate any unwelcome compile-time impact when not using AA, only one store
is kept in the list per object when not using AA.
This, along with a stack coloring change to come shortly, will provide a test
case, fix PR18497 (and allow LLVM to compile itself using -enable-aa-sched-mi
on x86-64).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199657 91177308-0d34-0410-b5e6-96231b3b80d8
The addition of IC_OPSIZE_ADSIZE in r198759 wasn't quite complete. It
also turns out to have been unnecessary. The disassembler handles the
AdSize prefix for itself, and doesn't care about the difference between
(e.g.) MOV8ao8 and MOB8ao8_16 definitions. So just let them coexist and
don't worry about it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199654 91177308-0d34-0410-b5e6-96231b3b80d8
The disassembler has a special case for 'L' vs. 'W' in its heuristic for
checking for 32-bit and 16-bit equivalents. We could expand the heuristic,
but better just to be consistent in using the 'L' suffix.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199652 91177308-0d34-0410-b5e6-96231b3b80d8
Not quite sure why this was marked isAsmParserOnly, but it means that the
disassembler can't see it either.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199651 91177308-0d34-0410-b5e6-96231b3b80d8
When disassembling in 16-bit mode the meaning of the OpSize bit is
inverted. Instructions found in the IC_OPSIZE context will actually
*not* have the 0x66 prefix, and instructions in the IC context will
have the 0x66 prefix. Make use of the existing special-case handling
for the 0x66 prefix being in the wrong place, to cope with this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199650 91177308-0d34-0410-b5e6-96231b3b80d8
Aside from cleaning up the code, this also adds support for the -code16
environment and actually enables the MODE_16BIT mode that was previously
not accessible.
There is no point adding any testing for 16-bit yet though; basically
nothing will work because we aren't handling the OpSize prefix correctly
for 16-bit mode.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199649 91177308-0d34-0410-b5e6-96231b3b80d8
various opt verifier commandline options.
Mostly mechanical wiring of the verifier to the new pass manager.
Exercises one of the more unusual aspects of it -- a pass can be either
a module or function pass interchangably. If this is ever problematic,
we can make things more constrained, but for things like the verifier
where there is an "obvious" applicability at both levels, it seems
convenient.
This is the next-to-last piece of basic functionality left to make the
opt commandline driving of the new pass manager minimally functional for
testing and further development. There is still a lot to be done there
(notably the factoring into .def files to kill the current boilerplate
code) but it is relatively uninteresting. The only interesting bit left
for minimal functionality is supporting the registration of analyses.
I'm planning on doing that on top of the .def file switch mostly because
the boilerplate for the analyses would be significantly worse.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199646 91177308-0d34-0410-b5e6-96231b3b80d8
Add support for the symbol(tlsldo) relocation. This is required in order to
solve PR18554.
Reviewed by R. Golin, A. Korobeynikov.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199644 91177308-0d34-0410-b5e6-96231b3b80d8
ADDITIONAL_HEADERS is intended to add header files for IDEs as hint.
For example:
add_llvm_library(LLVMSupport
Host.cpp
ADDITIONAL_HEADERS
Unix/Host.inc
Windows/Host.inc
)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199639 91177308-0d34-0410-b5e6-96231b3b80d8
coding standards, and instead fix the existing section.
Thanks to Daniel Jasper for pointing out we already had a section
devoted to this topic. Instead of adding sections, just hack on this
section some. Also fix the example in the anonymous namespace section
below it to agree with the new advice.
As a re-cap, this switches the LLVM preferred style to never indent
namespaces. Having two approaches just led to endless (and utterly
pointless) debates about what was "small enough". This wasn't helping
anyone. The no-indent rule is easy to understand and doesn't really make
anything harder to read. Moreover, with tools like clang-format it is
considerably nicer to have simple consistent rules.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199637 91177308-0d34-0410-b5e6-96231b3b80d8
type units were enabled. The crux of the issue is that the
addDwarfTypeUnitType routine can end up being indirectly recursive. In
this case, the reference into the dense map (TU) became invalid by the
time we popped all the way back and used it to add the DIE type
signature.
Instead, use early return in the case where we can bypass the recursive
step and creating a type unit. Then use the pointer to the new type unit
to set up the DIE type signature in the case where we have to.
I tried really hard to reduce a testcase for this, but it's really
annoying. You have to get this to be mid-recursion when the densemap
grows. Even if we got a test case for this today, it'd be very unlikely
to continue exercising this pattern.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199630 91177308-0d34-0410-b5e6-96231b3b80d8
This logic hadn't been updated to handle FastMathFlags, and it took me a while to detect it because it doesn't show up in a simple search for CreateFAdd.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199629 91177308-0d34-0410-b5e6-96231b3b80d8
Have I mentioned that functions returning true on error and false on
success are confusing? They're more confusing when their name is
"verify". Anyways...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199622 91177308-0d34-0410-b5e6-96231b3b80d8
For FCMEQ, FCMGE, FCMGT, FCMLE and FCMLT, floating point zero will be
printed as #0.0 instead of #0. To support the history codes using #0,
we consider to let asm parser accept both #0.0 and #0.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199621 91177308-0d34-0410-b5e6-96231b3b80d8
(and to mention namespace ending comments). This is based on a quick
discussion on the developer mailing list where there was essentially no
objections to a simple and consistent rule. This should avoid future
debates about whether or not a namespace is "big enough" to indent. It
also matches clang-format's current behavior with LLVM source code which
hasn't really seen any opposition in code reviews that I spot checked.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199620 91177308-0d34-0410-b5e6-96231b3b80d8
This was due to arithmetic overflow in the getNumBits() computation. Now we
cast BitWidth to a uint64_t so that does not occur during the computation. After
the computation is complete, the uint64_t is truncated when the function
returns.
I know that this is not something that is likely to happen, but it *IS* a valid
input and we should not blow up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199609 91177308-0d34-0410-b5e6-96231b3b80d8
In LLVM build tree, they points corresponding INTDIR.
In Clang standalone tree, they points external dir (llvm-config's --bindir and --libdir).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199595 91177308-0d34-0410-b5e6-96231b3b80d8
intrinsics.
Reported on the list by Evan with a couple of attempts to fix, but it
took a while to dig down to the root cause. There are two overlapping
bugs here, both centering around the circumstance of discovering
a memcpy operand which is known to be completely outside the bounds of
the alloca.
First, we need to kill the *other* side of the memcpy if it was added to
this alloca. Otherwise we'll factor it into our slicing and try to
rewrite it even though we know for a fact that it is dead. This is made
more tricky because we can visit the sides in either order. So we have
to both kill the other side and skip instructions marked as dead. The
latter really should be goodness in every case, but here is a matter of
correctness.
Second, we need to actually remove the *uses* of the alloca by the
memcpy when queuing it for later deletion. Otherwise it may still be
using the alloca when we go to promote it (if the rewrite re-uses the
existing alloca instruction). Do this by factoring out the
use-clobbering used when for nixing a Phi argument and re-using it
across the operands of a to-be-deleted instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199590 91177308-0d34-0410-b5e6-96231b3b80d8
Ensure that the tag types are reflected on a replacement. This is particularly
important for the compatibility tag which has multiple representations where the
last definition wins.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199577 91177308-0d34-0410-b5e6-96231b3b80d8
This moves the ARM build attributes definitions and support routines into the
Support library. The support routines simply permit the conversion of the value
to and from a string representation.
The movement is prompted in order to permit access to the constants and string
representations from readobj in order to facilitate decoding of the attributes
section.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199575 91177308-0d34-0410-b5e6-96231b3b80d8
Tag_nodefaults is even and greater than 32 and thus does not need the special
check to fall into the correct category.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199574 91177308-0d34-0410-b5e6-96231b3b80d8
a reduction.
Really. Under certain circumstances (the use list of an instruction has to be
set up right - hence the extra pass in the test case) we would not recognize
when a value in a potential reduction cycle was used multiple times by the
reduction cycle.
Fixes PR18526.
radar://15851149
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199570 91177308-0d34-0410-b5e6-96231b3b80d8
This makes the 'verifyFunction' and 'verifyModule' functions totally
independent operations on the LLVM IR. It also cleans up their API a bit
by lifting the abort behavior into their clients and just using an
optional raw_ostream parameter to control printing.
The implementation of the verifier is now just an InstVisitor with no
multiple inheritance. It also is significantly more const-correct, and
hides the const violations internally. The two layers that force us to
break const correctness are building a DomTree and dispatching through
the InstVisitor.
A new VerifierPass is used to implement the legacy pass manager
interface in terms of the other pieces.
The error messages produced may be slightly different now, and we may
have slightly different short circuiting behavior with different usage
models of the verifier, but generally everything works equivalently and
this unblocks wiring the verifier up to the new pass manager.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199569 91177308-0d34-0410-b5e6-96231b3b80d8
one, but not create one. This is useful in the verifier when we want to
query the constant if it exists but not create one. To be used in an
upcoming commit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199568 91177308-0d34-0410-b5e6-96231b3b80d8
