shim between the TargetTransformInfo immutable pass and the Subtarget
via the TargetMachine and Function. Migrate a single call from
BasicTargetTransformInfo as an example and provide shims where TargetMachine
begins taking a Function to determine the subtarget.
No functional change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218004 91177308-0d34-0410-b5e6-96231b3b80d8
This improves other optimizations such as LSR. A sext may be added to the
compare's other operand, but this can often be hoisted outside of the loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217953 91177308-0d34-0410-b5e6-96231b3b80d8
We used to crash processing any relevant @llvm.assume on a 32-bit target
(because we'd ask SE to subtract expressions of differing types). I've copied
our 'simple.ll' test, but with the data layout from arm-linux-gnueabihf to get
some meaningful test coverage here.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217574 91177308-0d34-0410-b5e6-96231b3b80d8
The routine that determines an alignment given some SCEV returns zero if the
answer is unknown. In a case where we could determine the increment of an
AddRec but not the starting alignment, we would compute the integer modulus by
zero (which is illegal and traps). Prevent this by returning early if either
the start or increment alignment is unknown (zero).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217544 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch moves the profile reading logic out of the Sample Profile
transformation into a generic profile reader facility in
lib/ProfileData.
The intent is to use this new reader to implement a sample profile
reader/writer that can be used to convert sample profiles from external
sources into LLVM.
This first patch introduces no functional changes. It moves the profile
reading code from lib/Transforms/SampleProfile.cpp into
lib/ProfileData/SampleProfReader.cpp.
In subsequent patches I will:
- Add a bitcode format for sample profiles to allow for more efficient
encoding of the profile.
- Add a writer for both text and bitcode format profiles.
- Add a 'convert' command to llvm-profdata to be able to convert between
the two (and serve as entry point for other sample profile formats).
Reviewers: bogner, echristo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D5250
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217437 91177308-0d34-0410-b5e6-96231b3b80d8
This change teaches LazyValueInfo to use the @llvm.assume intrinsic. Like with
the known-bits change (r217342), this requires feeding a "context" instruction
pointer through many functions. Aside from a little refactoring to reuse the
logic that turns predicates into constant ranges in LVI, the only new code is
that which can 'merge' the range from an assumption into that otherwise
computed. There is also a small addition to JumpThreading so that it can have
LVI use assumptions in the same block as the comparison feeding a conditional
branch.
With this patch, we can now simplify this as expected:
int foo(int a) {
__builtin_assume(a > 5);
if (a > 3) {
bar();
return 1;
}
return 0;
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217345 91177308-0d34-0410-b5e6-96231b3b80d8
This adds a ScalarEvolution-powered transformation that updates load, store and
memory intrinsic pointer alignments based on invariant((a+q) & b == 0)
expressions. Many of the simple cases we can get with ValueTracking, but we
still need something like this for the more complicated cases (such as those
with an offset) that require some algebra. Note that gcc's
__builtin_assume_aligned's optional third argument provides exactly for this
kind of 'misalignment' offset for which this kind of logic is necessary.
The primary motivation is to fixup alignments for vector loads/stores after
vectorization (and unrolling). This pass is added to the optimization pipeline
just after the SLP vectorizer runs (which, admittedly, does not preserve SE,
although I imagine it could). Regardless, I actually don't think that the
preservation matters too much in this case: SE computes lazily, and this pass
won't issue any SE queries unless there are any assume intrinsics, so there
should be no real additional cost in the common case (SLP does preserve DT and
LoopInfo).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217344 91177308-0d34-0410-b5e6-96231b3b80d8
This change, which allows @llvm.assume to be used from within computeKnownBits
(and other associated functions in ValueTracking), adds some (optional)
parameters to computeKnownBits and friends. These functions now (optionally)
take a "context" instruction pointer, an AssumptionTracker pointer, and also a
DomTree pointer, and most of the changes are just to pass this new information
when it is easily available from InstSimplify, InstCombine, etc.
As explained below, the significant conceptual change is that known properties
of a value might depend on the control-flow location of the use (because we
care that the @llvm.assume dominates the use because assumptions have
control-flow dependencies). This means that, when we ask if bits are known in a
value, we might get different answers for different uses.
The significant changes are all in ValueTracking. Two main changes: First, as
with the rest of the code, new parameters need to be passed around. To make
this easier, I grouped them into a structure, and I made internal static
versions of the relevant functions that take this structure as a parameter. The
new code does as you might expect, it looks for @llvm.assume calls that make
use of the value we're trying to learn something about (often indirectly),
attempts to pattern match that expression, and uses the result if successful.
By making use of the AssumptionTracker, the process of finding @llvm.assume
calls is not expensive.
Part of the structure being passed around inside ValueTracking is a set of
already-considered @llvm.assume calls. This is to prevent a query using, for
example, the assume(a == b), to recurse on itself. The context and DT params
are used to find applicable assumptions. An assumption needs to dominate the
context instruction, or come after it deterministically. In this latter case we
only handle the specific case where both the assumption and the context
instruction are in the same block, and we need to exclude assumptions from
being used to simplify their own ephemeral values (those which contribute only
to the assumption) because otherwise the assumption would prove its feeding
comparison trivial and would be removed.
This commit adds the plumbing and the logic for a simple masked-bit propagation
(just enough to write a regression test). Future commits add more patterns
(and, correspondingly, more regression tests).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217342 91177308-0d34-0410-b5e6-96231b3b80d8
This adds a set of utility functions for collecting 'ephemeral' values. These
are LLVM IR values that are used only by @llvm.assume intrinsics (directly or
indirectly), and thus will be removed prior to code generation, implying that
they should be considered free for certain purposes (like inlining). The
inliner's cost analysis, and a few other passes, have been updated to account
for ephemeral values using the provided functionality.
This functionality is important for the usability of @llvm.assume, because it
limits the "non-local" side-effects of adding llvm.assume on inlining, loop
unrolling, etc. (these are hints, and do not generate code, so they should not
directly contribute to estimates of execution cost).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217335 91177308-0d34-0410-b5e6-96231b3b80d8
This adds an immutable pass, AssumptionTracker, which keeps a cache of
@llvm.assume call instructions within a module. It uses callback value handles
to keep stale functions and intrinsics out of the map, and it relies on any
code that creates new @llvm.assume calls to notify it of the new instructions.
The benefit is that code needing to find @llvm.assume intrinsics can do so
directly, without scanning the function, thus allowing the cost of @llvm.assume
handling to be negligible when none are present.
The current design is intended to be lightweight. We don't keep track of
anything until we need a list of assumptions in some function. The first time
this happens, we scan the function. After that, we add/remove @llvm.assume
calls from the cache in response to registration calls and ValueHandle
callbacks.
There are no new direct test cases for this pass, but because it calls it
validation function upon module finalization, we'll pick up detectable
inconsistencies from the other tests that touch @llvm.assume calls.
This pass will be used by follow-up commits that make use of @llvm.assume.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217334 91177308-0d34-0410-b5e6-96231b3b80d8
LinearFunctionTestReplace tries to use the *next* indvar to compare
against when possible. However, it may be the case that the calculation
for the next indvar has NUW/NSW flags and that it may only be safely
used inside the loop. Using it in a comparison to calculate the exit
condition could result in observing poison.
This fixes PR20680.
Differential Revision: http://reviews.llvm.org/D5174
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217102 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
BBs might contain non-LCSSA'd values after the LCSSA pass is run if they
are unreachable from the entry block.
Normally, the users of the instruction would be PHIs but the unreachable
BBs have normal users; rewrite their uses to be undef values.
An alternative fix could involve fixing this at LCSSA but that would
require this invariant to hold after subsequent transforms. If a BB
created an unreachable block, they would be in violation of this.
This fixes PR19798.
Differential Revision: http://reviews.llvm.org/D5146
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216911 91177308-0d34-0410-b5e6-96231b3b80d8
SROA may decide that it needs to insert a bitcast and would set it's
insertion point before a PHI. This will create an invalid module
right quick.
Instead, choose the first insertion point in the basic block that holds
our PHI.
This fixes PR20822.
Differential Revision: http://reviews.llvm.org/D5141
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216891 91177308-0d34-0410-b5e6-96231b3b80d8
chain became completely broken here as *all* intrinsic users ended up
being skipped, and the ones that seemed to be singled out were actually
the exact wrong set.
This is a great example of why long else-if chains can be easily
confusing. Switch the entire code to use early exits and early continues
to have simpler (and more importantly, correct) logic here, as well as
fixing the reversed logic for detecting and continuing on lifetime
intrinsics.
I've also significantly cleaned up the test case and added another test
case demonstrating an example where the optimization is not (trivially)
safe to perform.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216871 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Fixes PR20425.
During slice building, if all of the incoming values of a PHI node are the same, replace the PHI node with the common value. This simplification makes alloca's used by PHI nodes easier to promote.
Test Plan: Added three more tests in phi-and-select.ll
Reviewers: nlewycky, eliben, meheff, chandlerc
Reviewed By: chandlerc
Subscribers: zinovy.nis, hfinkel, baldrick, llvm-commits
Differential Revision: http://reviews.llvm.org/D4659
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216299 91177308-0d34-0410-b5e6-96231b3b80d8
In this case, we are creating an x86_fp80 slice for a union from C where
the padding bytes may contain real data. An x86_fp80 alloca is 16 bytes,
and that's just fine. We can't, however, use regular loads and stores to
access the slice, because the store size is only 10 bytes / 80 bits.
Instead, use memcpy and memset.
Fixes PR18726.
Reviewed By: chandlerc
Differential Revision: http://reviews.llvm.org/D5012
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216248 91177308-0d34-0410-b5e6-96231b3b80d8
Currently only "add nsw" are widened. This patch eliminates tons of "sext" instructions for 64 bit code (and the corresponding target code) in cases like:
int N = 100;
float **A;
void foo(int x0, int x1)
{
float * A_cur = &A[0][0];
float * A_next = &A[1][0];
for(int x = x0; x < x1; ++x).
{
// Currently only [x+N] case is widened. Others 2 cases lead to sext.
// This patch fixes it, so all 3 cases do not need sext.
const float div = A_cur[x + N] + A_cur[x - N] + A_cur[x * N];
A_next[x] = div;
}
}
...
> clang++ test.cpp -march=core-avx2 -Ofast -fno-unroll-loops -fno-tree-vectorize -S -o -
Differential Revision: http://reviews.llvm.org/D4695
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216160 91177308-0d34-0410-b5e6-96231b3b80d8
Replace the old code in GVN and BBVectorize with it. Update SimplifyCFG to use
it.
Patch by Björn Steinbrink!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215723 91177308-0d34-0410-b5e6-96231b3b80d8
Vector instructions are (still) not supported for either integer or floating
point. Hopefully, that work will be landed shortly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215647 91177308-0d34-0410-b5e6-96231b3b80d8
this case, the code path dealing with vector promotion was missing the explicit
checks for lifetime intrinsics that were present on the corresponding integer
promotion path.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215148 91177308-0d34-0410-b5e6-96231b3b80d8
Optimize the following IR:
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
%2 = bitcast i8* %1 to i32*
; This store is dead and should be removed
store i32 0, i32* %2, align 4
Memory returned by calloc is guaranteed to be zero initialized. If the value being stored is the constant zero (and the store is not otherwise observable across threads), we can delete the store. If the store is to an out of bounds address, it is undefined and thus also removable.
Reviewed By: nicholas
Differential Revision: http://reviews.llvm.org/D3942
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214897 91177308-0d34-0410-b5e6-96231b3b80d8
Instead of moving out the data in a ErrorOr<std::unique_ptr<Foo>>, get
a reference to it.
Thanks to David Blaikie for the suggestion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214516 91177308-0d34-0410-b5e6-96231b3b80d8
hint) the loop unroller replaces the llvm.loop.unroll.count metadata with
llvm.loop.unroll.disable metadata to prevent any subsequent unrolling
passes from unrolling more than the hint indicates. This patch fixes
an issue where loop unrolling could be disabled for other loops as well which
share the same llvm.loop metadata.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213900 91177308-0d34-0410-b5e6-96231b3b80d8
This commit adds scoped noalias metadata. The primary motivations for this
feature are:
1. To preserve noalias function attribute information when inlining
2. To provide the ability to model block-scope C99 restrict pointers
Neither of these two abilities are added here, only the necessary
infrastructure. In fact, there should be no change to existing functionality,
only the addition of new features. The logic that converts noalias function
parameters into this metadata during inlining will come in a follow-up commit.
What is added here is the ability to generally specify noalias memory-access
sets. Regarding the metadata, alias-analysis scopes are defined similar to TBAA
nodes:
!scope0 = metadata !{ metadata !"scope of foo()" }
!scope1 = metadata !{ metadata !"scope 1", metadata !scope0 }
!scope2 = metadata !{ metadata !"scope 2", metadata !scope0 }
!scope3 = metadata !{ metadata !"scope 2.1", metadata !scope2 }
!scope4 = metadata !{ metadata !"scope 2.2", metadata !scope2 }
Loads and stores can be tagged with an alias-analysis scope, and also, with a
noalias tag for a specific scope:
... = load %ptr1, !alias.scope !{ !scope1 }
... = load %ptr2, !alias.scope !{ !scope1, !scope2 }, !noalias !{ !scope1 }
When evaluating an aliasing query, if one of the instructions is associated
with an alias.scope id that is identical to the noalias scope associated with
the other instruction, or is a descendant (in the scope hierarchy) of the
noalias scope associated with the other instruction, then the two memory
accesses are assumed not to alias.
Note that is the first element of the scope metadata is a string, then it can
be combined accross functions and translation units. The string can be replaced
by a self-reference to create globally unqiue scope identifiers.
[Note: This overview is slightly stylized, since the metadata nodes really need
to just be numbers (!0 instead of !scope0), and the scope lists are also global
unnamed metadata.]
Existing noalias metadata in a callee is "cloned" for use by the inlined code.
This is necessary because the aliasing scopes are unique to each call site
(because of possible control dependencies on the aliasing properties). For
example, consider a function: foo(noalias a, noalias b) { *a = *b; } that gets
inlined into bar() { ... if (...) foo(a1, b1); ... if (...) foo(a2, b2); } --
now just because we know that a1 does not alias with b1 at the first call site,
and a2 does not alias with b2 at the second call site, we cannot let inlining
these functons have the metadata imply that a1 does not alias with b2.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213864 91177308-0d34-0410-b5e6-96231b3b80d8
In order to enable the preservation of noalias function parameter information
after inlining, and the representation of block-level __restrict__ pointer
information (etc.), additional kinds of aliasing metadata will be introduced.
This metadata needs to be carried around in AliasAnalysis::Location objects
(and MMOs at the SDAG level), and so we need to generalize the current scheme
(which is hard-coded to just one TBAA MDNode*).
This commit introduces only the necessary refactoring to allow for the
introduction of other aliasing metadata types, but does not actually introduce
any (that will come in a follow-up commit). What it does introduce is a new
AAMDNodes structure to hold all of the aliasing metadata nodes associated with
a particular memory-accessing instruction, and uses that structure instead of
the raw MDNode* in AliasAnalysis::Location, etc.
No functionality change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213859 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r213474 (and r213475), which causes a miscompile on
a stage2 LTO build. I'll reply on the list in a moment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213562 91177308-0d34-0410-b5e6-96231b3b80d8
Prevents hoisting of loads above stores and sinking of stores below loads
in MergedLoadStoreMotion.cpp (rdar://15991737)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213497 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: This patch introduces two new iterator ranges and updates existing code to use it. No functional change intended.
Test Plan: All tests (make check-all) still pass.
Reviewers: dblaikie
Reviewed By: dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D4481
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213474 91177308-0d34-0410-b5e6-96231b3b80d8
Merges equivalent loads on both sides of a hammock/diamond
and hoists into into the header.
Merges equivalent stores on both sides of a hammock/diamond
and sinks it to the footer.
Can enable if conversion and tolerate better load misses
and store operand latencies.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213396 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Converting outermost zext(a) to sext(a) causes worse code when the
computation of zext(a) could be reused. For example, after converting
... = array[zext(a)]
... = array[zext(a) + 1]
to
... = array[sext(a)]
... = array[zext(a) + 1],
the program computes sext(a), which is actually unnecessary. I added one
test in split-gep-and-gvn.ll to illustrate this scenario.
Also, with r211281 and r211084, we annotate more "nuw" tags to
computation involving CUDA intrinsics such as threadIdx.x. These
annotations help with splitting GEP a lot, rendering the benefit we get
from this reverted optimization only marginal.
Test Plan: make check-all
Reviewers: eliben, meheff
Reviewed By: meheff
Subscribers: jholewinski, llvm-commits
Differential Revision: http://reviews.llvm.org/D4542
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213209 91177308-0d34-0410-b5e6-96231b3b80d8
not properly handle the case where the predecessor block was the entry block to
the function. The only in-tree client of this is JumpThreading, which worked
around the issue in its own code. This patch moves the solution into the helper
so that JumpThreading (and other clients) do not have to replicate the same fix
everywhere.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212875 91177308-0d34-0410-b5e6-96231b3b80d8
This is the one remaining place I see where passing
isSafeToSpeculativelyExecute a DataLayout pointer might matter (at least for
loads) -- I think I got the others in r212720. Most of the other remaining
callers of isSafeToSpeculativelyExecute only use it for call sites (or
otherwise exclude loads).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212730 91177308-0d34-0410-b5e6-96231b3b80d8
isSafeToSpeculativelyExecute can optionally take a DataLayout pointer. In the
past, this was mainly used to make better decisions regarding divisions known
not to trap, and so was not all that important for users concerned with "cheap"
instructions. However, now it also helps look through bitcasts for
dereferencable loads, and will also be important if/when we add a
dereferencable pointer attribute.
This is some initial work to feed a DataLayout pointer through to callers of
isSafeToSpeculativelyExecute, generally where one was already available.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212720 91177308-0d34-0410-b5e6-96231b3b80d8
isDereferenceablePointer should not give up upon encountering any bitcast. If
we're casting from a pointer to a larger type to a pointer to a small type, we
can continue by examining the bitcast's operand. This missing capability
was noted in a comment in the function.
In order for this to work, isDereferenceablePointer now takes an optional
DataLayout pointer (essentially all callers already had such a pointer
available). Most code uses isDereferenceablePointer though
isSafeToSpeculativelyExecute (which already took an optional DataLayout
pointer), and to enable the LICM test case, LICM needs to actually provide its DL
pointer to isSafeToSpeculativelyExecute (which it was not doing previously).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212686 91177308-0d34-0410-b5e6-96231b3b80d8
If both instructions to be replaced are marked invariant the resulting
instruction is invariant.
rdar://13358910
Fix by Erik Eckstein!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211801 91177308-0d34-0410-b5e6-96231b3b80d8
[LLVM part]
These patches rename the loop unrolling and loop vectorizer metadata
such that they have a common 'llvm.loop.' prefix. Metadata name
changes:
llvm.vectorizer.* => llvm.loop.vectorizer.*
llvm.loopunroll.* => llvm.loop.unroll.*
This was a suggestion from an earlier review
(http://reviews.llvm.org/D4090) which added the loop unrolling
metadata.
Patch by Mark Heffernan.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211710 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes exponential compilation complexity in PR19835, caused by
LICM::sink not handling the following pattern well:
f = op g
e = op f, g
d = op e
c = op d, e
b = op c
a = op b, c
When an instruction with N uses is sunk, each of its operands gets N
new uses (all of them - phi nodes). In the example above, if a had 1
use, c would have 2, e would have 4, and g would have 8.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211673 91177308-0d34-0410-b5e6-96231b3b80d8
r199771 accidently broke the logic that makes sure that SROA only splits
load on byte boundaries. If such a split happens, some bits get lost
when reassembling loads of wider types, causing data corruption.
Move the width check up to reject such splits early, avoiding the
corruption. Fixes PR19250.
Patch by: Björn Steinbrink <bsteinbr@gmail.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211082 91177308-0d34-0410-b5e6-96231b3b80d8
[This is resubmitting r210721, which was reverted due to suspected breakage
which turned out to be unrelated].
Some extra review comments were addressed. See D4090 and D4147 for more details.
The Clang change that produces this metadata was committed in r210667
Patch by Mark Heffernan.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211076 91177308-0d34-0410-b5e6-96231b3b80d8
This patch is to move GlobalMerge pass from Transform/Scalar
to CodeGen, because GlobalMerge depends on TargetMachine.
In the mean time, the macro INITIALIZE_TM_PASS is also moved
to CodeGen/Passes.h. With this fix we can avoid making
libScalarOpts depend on libCodeGen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210951 91177308-0d34-0410-b5e6-96231b3b80d8
This commit adds a weak variant of the cmpxchg operation, as described
in C++11. A cmpxchg instruction with this modifier is permitted to
fail to store, even if the comparison indicated it should.
As a result, cmpxchg instructions must return a flag indicating
success in addition to their original iN value loaded. Thus, for
uniformity *all* cmpxchg instructions now return "{ iN, i1 }". The
second flag is 1 when the store succeeded.
At the DAG level, a new ATOMIC_CMP_SWAP_WITH_SUCCESS node has been
added as the natural representation for the new cmpxchg instructions.
It is a strong cmpxchg.
By default this gets Expanded to the existing ATOMIC_CMP_SWAP during
Legalization, so existing backends should see no change in behaviour.
If they wish to deal with the enhanced node instead, they can call
setOperationAction on it. Beware: as a node with 2 results, it cannot
be selected from TableGen.
Currently, no use is made of the extra information provided in this
patch. Test updates are almost entirely adapting the input IR to the
new scheme.
Summary for out of tree users:
------------------------------
+ Legacy Bitcode files are upgraded during read.
+ Legacy assembly IR files will be invalid.
+ Front-ends must adapt to different type for "cmpxchg".
+ Backends should be unaffected by default.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210903 91177308-0d34-0410-b5e6-96231b3b80d8
Enable value forwarding for loads from `calloc()` without an intervening
store.
This change extends GVN to handle the following case:
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
%2 = bitcast i8* %1 to i32*
; This load is trivially constant zero
%3 = load i32* %2, align 4
This is analogous to the handling for `malloc()` in the same places.
`malloc()` returns `undef`; `calloc()` returns a zero value. Note that
it is correct to return zero even for out of bounds GEPs since the
result of such a GEP would be undefined.
Patch by Philip Reames!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210828 91177308-0d34-0410-b5e6-96231b3b80d8
Pass initialization requires to initialize TargetMachine for back-end
specific passes. This commit creates a new macro INITIALIZE_TM_PASS to
simplify this kind of initialization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210641 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is to improve global merge pass and support global symbol merge.
The global symbol merge is not enabled by default. For aarch64, we need some
more back-end fix to make it really benifit ADRP CSE.
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For each array index that is in the form of zext(a), convert it to sext(a)
if we can prove zext(a) <= max signed value of typeof(a). The conversion
helps to split zext(x + y) into sext(x) + sext(y).
Reviewed in http://reviews.llvm.org/D4060
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zext(a + b) != zext(a) + zext(b) even if a + b >= 0 && b >= 0.
e.g., a = i4 0b1111, b = i4 0b0001
zext a + b to i8 = zext 0b0000 to i8 = 0b00000000
(zext a to i8) + (zext b to i8) = 0b00001111 + 0b00000001 = 0b00010000
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Most issues are on mishandling s/zext.
Fixes:
1. When rebuilding new indices, s/zext should be distributed to
sub-expressions. e.g., sext(a +nsw (b +nsw 5)) = sext(a) + sext(b) + 5 but not
sext(a + b) + 5. This also affects the logic of recursively looking for a
constant offset, we need to include s/zext into the context of the searching.
2. Function find should return the bitwidth of the constant offset instead of
always sign-extending it to i64.
3. Stop shortcutting zext'ed GEP indices. LLVM conceptually sign-extends GEP
indices to pointer-size before computing the address. Therefore, gep base,
zext(a + b) != gep base, a + b
Improvements:
1. Add an optimization for splitting sext(a + b): if a + b is proven
non-negative (e.g., used as an index of an inbound GEP) and one of a, b is
non-negative, sext(a + b) = sext(a) + sext(b)
2. Function Distributable checks whether both sext and zext can be distributed
to operands of a binary operator. This helps us split zext(sext(a + b)) to
zext(sext(a) + zext(sext(b)) when a + b does not signed or unsigned overflow.
Refactoring:
Merge some common logic of handling add/sub/or in find.
Testing:
Add many tests in split-gep.ll and split-gep-and-gvn.ll to verify the changes
we made.
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Handle "X + ~X" -> "-1" in the function Value *Reassociate::OptimizeAdd(Instruction *I, SmallVectorImpl<ValueEntry> &Ops);
This patch implements:
TODO: We could handle "X + ~X" -> "-1" if we wanted, since "-X = ~X+1".
Patch by Rahul Jain!
Differential Revision: http://reviews.llvm.org/D3835
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This is an enhancement to SeparateConstOffsetFromGEP. With this patch, we can
extract a constant offset from "s/zext and/or/xor A, B".
Added a new test @ext_or to verify this enhancement.
Refactoring the code, I also extracted some common logic to function
Distributable.
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and via the command line, mirroring similar functionality in LoopUnroll. In
situations where clients used custom unrolling thresholds, their intent could
previously be foiled by LoopRotate having a hardcoded threshold.
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Fixed a TODO in r207783.
Add the extracted constant offset using GEP instead of ugly
ptrtoint+add+inttoptr. Using GEP simplifies future optimizations and makes IR
easier to understand.
Updated all affected tests, and added a new test in split-gep.ll to cover a
corner case where emitting uglygep is necessary.
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Summary:
This adds two new diagnostics: -pass-remarks-missed and
-pass-remarks-analysis. They take the same values as -pass-remarks but
are intended to be triggered in different contexts.
-pass-remarks-missed is used by LLVMContext::emitOptimizationRemarkMissed,
which passes call when they tried to apply a transformation but
couldn't.
-pass-remarks-analysis is used by LLVMContext::emitOptimizationRemarkAnalysis,
which passes call when they want to inform the user about analysis
results.
The patch also:
1- Adds support in the inliner for the two new remarks and a
test case.
2- Moves emitOptimizationRemark* functions to the llvm namespace.
3- Adds an LLVMContext argument instead of making them member functions
of LLVMContext.
Reviewers: qcolombet
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D3682
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This commit introduces a canonical representation for the formulae.
Basically, as soon as a formula has more that one base register, the scaled
register field is used for one of them. The register put into the scaled
register is preferably a loop variant.
The commit refactors how the formulae are built in order to produce such
representation.
This yields a more accurate, but still perfectible, cost model.
<rdar://problem/16731508>
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This reverts commit r208934.
The patch depends on aliases to GEPs with non zero offsets. That is not
supported and fairly broken.
The good news is that GlobalAlias is being redesigned and will have support
for offsets, so this patch should be a nice match for it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208978 91177308-0d34-0410-b5e6-96231b3b80d8
This commit implements two command line switches -global-merge-on-external
and -global-merge-aligned, and both of them are false by default, so this
optimization is disabled by default for all targets.
For ARM64, some back-end behaviors need to be tuned to get this optimization
further enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208934 91177308-0d34-0410-b5e6-96231b3b80d8
Iterating over a DenseMaop is non-deterministic and results to unpredictable IR
output.
Based on a patch by Daniel Reynaud!
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The number of tail call to loop conversions remains the same (1618 by my count).
The new algorithm does a local scan over the use-def chains to identify local "alloca-derived" values, as well as points where the alloca could escape. Then, a visit over the CFG marks blocks as being before or after the allocas have escaped, and annotates the calls accordingly.
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Otherwise we use the same threshold as for complete unrolling, which is
way too high. This made us unroll any loop smaller than 150 instructions
by 8 times, but only if someone specified -march=core2 or better,
which happens to be the default on darwin.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207940 91177308-0d34-0410-b5e6-96231b3b80d8
address to AnalyzeLoadFromClobberingLoad. This fixes a bug in load-PRE where
PRE is applied to a load that is not partially redundant.
<rdar://problem/16638765>.
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This optimization merges the common part of a group of GEPs, so we can compute
each pointer address by adding a simple offset to the common part.
The optimization is currently only enabled for the NVPTX backend, where it has
a large payoff on some benchmarks.
Review: http://reviews.llvm.org/D3462
Patch by Jingyue Wu.
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clang directly from the LLVM test suite! That doesn't work. I've
followed up on the review thread to try and get a viable solution sorted
out, but trying to get the tree clean here.
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more than 1 instruction. The caller need to be aware of this
and adjust instruction iterators accordingly.
rdar://16679376
Repaired r207302.
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more than 1 instruction. The caller need to be aware of this
and adjust instruction iterators accordingly.
rdar://16679376
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Consider this use from the new testcase:
LSR Use: Kind=ICmpZero, Offsets={0}, widest fixup type: i32
reg({1000,+,-1}<nw><%for.body>)
-3003 + reg({3,+,3}<nw><%for.body>)
-1001 + reg({1,+,1}<nuw><nsw><%for.body>)
-1000 + reg({0,+,1}<nw><%for.body>)
-3000 + reg({0,+,3}<nuw><%for.body>)
reg({-1000,+,1}<nw><%for.body>)
reg({-3000,+,3}<nsw><%for.body>)
This is the last use we consider for a solution in SolveRecurse, so CurRegs is
a large set. (CurRegs is the set of registers that are needed by the
previously visited uses in the in-progress solution.)
ReqRegs is {
{3,+,3}<nw><%for.body>,
{1,+,1}<nuw><nsw><%for.body>
}
This is the intersection of the regs used by any of the formulas for the
current use and CurRegs.
Now, the code requires a formula to contain *all* these regs (the comment is
simply wrong), otherwise the formula is immediately disqualified. Obviously,
no formula for this use contains two regs so they will all get disqualified.
The fix modifies the check to allow the formula in this case. The idea is
that neither of these formulae is introducing any new registers which is the
point of this early pruning as far as I understand.
In terms of set arithmetic, we now allow formulas whose used regs are a subset
of the required regs not just the other way around.
There are few more loops in the test-suite that are now successfully LSRed. I
have benchmarked those and found very minimal change.
Fixes <rdar://problem/13965777>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207271 91177308-0d34-0410-b5e6-96231b3b80d8
It's fishy to be changing the `std::vector<>` owned by the iterator, and
no one actual does it, so I'm going to remove the ability in a
subsequent commit. First, update the users.
<rdar://problem/14292693>
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In the case where the constant comes from a cloned cast instruction, the
materialization code has to go before the cloned cast instruction.
This commit fixes the method that finds the materialization insertion point
by making it aware of this case.
This fixes <rdar://problem/15532441>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206913 91177308-0d34-0410-b5e6-96231b3b80d8
definition below all of the header #include lines, lib/Transforms/...
edition.
This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.
Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206844 91177308-0d34-0410-b5e6-96231b3b80d8
The -tailcallelim pass should be checking if byval or inalloca args can
be captured before marking calls as tail calls. This was the real root
cause of PR7272.
With a better fix in place, revert the inliner change from r105255. The
test case it introduced still passes and has been moved to
test/Transforms/Inline/byval-tail-call.ll.
Reviewers: chandlerc
Differential Revision: http://reviews.llvm.org/D3403
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206789 91177308-0d34-0410-b5e6-96231b3b80d8
Implement DebugInfoVerifier, which steals verification relying on
DebugInfoFinder from Verifier.
- Adds LegacyDebugInfoVerifierPassPass, a ModulePass which wraps
DebugInfoVerifier. Uses -verify-di command-line flag.
- Change verifyModule() to invoke DebugInfoVerifier as well as
Verifier.
- Add a call to createDebugInfoVerifierPass() wherever there was a
call to createVerifierPass().
This implementation as a module pass should sidestep efficiency issues,
allowing us to turn debug info verification back on.
<rdar://problem/15500563>
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Also updated as many loops as I could find using df_begin/idf_begin -
strangely I found no uses of idf_begin. Is that just used out of tree?
Also a few places couldn't use df_begin because either they used the
member functions of the depth first iterators or had specific ordering
constraints (I added a comment in the latter case).
Based on a patch by Jim Grosbach. (Jim - you just had iterator_range<T>
where you needed iterator_range<idf_iterator<T>>)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206016 91177308-0d34-0410-b5e6-96231b3b80d8
This code is no longer usefull, because we only compute and use the
IDom once. There is no benefit in caching it anymore.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205498 91177308-0d34-0410-b5e6-96231b3b80d8
In preparation for an upcoming commit implementing unrolling preferences for
x86, this adds additional fields to the UnrollingPreferences structure:
- PartialThreshold and PartialOptSizeThreshold - Like Threshold and
OptSizeThreshold, but used when not fully unrolling. These are necessary
because we need different thresholds for full unrolling from those used when
partially unrolling (the full unrolling thresholds are generally going to be
larger).
- MaxCount - A cap on the unrolling factor when partially unrolling. This can
be used by a target to prevent the unrolled loop from exceeding some
resource limit independent of the loop size (such as number of branches).
There should be no functionality change for any in-tree targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205347 91177308-0d34-0410-b5e6-96231b3b80d8
The generic (concatenation) loop unroller is currently placed early in the
standard optimization pipeline. This is a good place to perform full unrolling,
but not the right place to perform partial/runtime unrolling. However, most
targets don't enable partial/runtime unrolling, so this never mattered.
However, even some x86 cores benefit from partial/runtime unrolling of very
small loops, and follow-up commits will enable this. First, we need to move
partial/runtime unrolling late in the optimization pipeline (importantly, this
is after SLP and loop vectorization, as vectorization can drastically change
the size of a loop), while keeping the full unrolling where it is now. This
change does just that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205264 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r203553, and follow-up commits r203558 and r203574.
I will follow this up on the mailinglist to do it in a way that won't
cause subtle PRE bugs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205009 91177308-0d34-0410-b5e6-96231b3b80d8
The cleanup code that removes dead cast instructions only removed them from the
basic block, but didn't delete them. This fix erases them now too.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204538 91177308-0d34-0410-b5e6-96231b3b80d8
A PHI node usually has only one value/basic block pair per incoming basic block.
In the case of a switch statement it is possible that a following PHI node may
have more than one such pair per incoming basic block. E.g.:
%0 = phi i64 [ 123456, %case2 ], [ 654321, %Entry ], [ 654321, %Entry ]
This is valid and the verfier doesn't complain, because both values are the
same.
Constant hoisting materializes the constant for each operand separately and the
value is still the same, but the variable names have changed. As a result the
verfier can't recognize anymore that they are the same value and complains.
This fix adds special update code for PHI node in constant hoisting to prevent
this corner case.
This fixes <rdar://problem/16394449>
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Extend the target hook to take also the operand index into account when
calculating the cost of the constant materialization.
Related to <rdar://problem/16381500>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204435 91177308-0d34-0410-b5e6-96231b3b80d8
Originally the algorithm would search for expensive constants and track their
users, which could be instructions and constant expressions. This change only
tracks the constants for instructions, but constant expressions are indirectly
covered too. If an operand is an constant expression, then we look through the
expression to find anny expensive constants.
The algorithm keep now track of the instruction and the operand index where the
constant is used. This allows more precise hoisting of constant materialization
code for PHI instructions, because we only hoist to the basic block of the
incoming operand. Before we had to find the idom of all PHI operands and hoist
the materialization code there.
This also makes updating of instructions easier. Before we had to keep track of
the original constant, find it in the instructions, and then replace it. Now we
can just simply update the operand.
Related to <rdar://problem/16381500>
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This simplifies working with the constant candidates and removes the tight
coupling between the map and the vector.
Related to <rdar://problem/16381500>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204431 91177308-0d34-0410-b5e6-96231b3b80d8
This commit extends the coverage of the constant hoisting pass, adds additonal
debug output and updates the function names according to the style guide.
Related to <rdar://problem/16381500>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204389 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The compiler does not always generate linkage names. If a function
has been inlined and its body elided, its linkage name may not be
generated.
When the binary executes, the profiler will use its unmangled name
when attributing samples. This results in unmangled names in the
input profile.
We are currently failing hard when this happens. However, in this case
all that happens is that we fail to attribute samples to the inlined
function. While this means fewer optimization opportunities, it should
not cause a compilation failure.
This patch accepts all valid function names, regardless of whether
they were mangled or not.
Reviewers: chandlerc
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D3087
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204142 91177308-0d34-0410-b5e6-96231b3b80d8
The "noduplicate" attribute of call instructions is sometimes queried directly
and sometimes through the cannotDuplicate() predicate. This patch streamlines
all queries to use the cannotDuplicate() predicate. It also adds this predicate
to InvokeInst, to mirror what CallInst has.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204049 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The sample profiler pass emits several error messages. Instead of
just aborting the compiler with report_fatal_error, we can emit
better messages using DiagnosticInfo.
This adds a new sub-class of DiagnosticInfo to handle the sample
profiler.
Reviewers: chandlerc, qcolombet
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D3086
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After r203553 overflow intrinsics and their non-intrinsic (normal)
instruction get hashed to the same value. This patch prevents PRE from
moving an instruction into a predecessor block, and trying to add a phi
node that gets two different types (the intrinsic result and the
non-intrinsic result), resulting in a failing assert.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203574 91177308-0d34-0410-b5e6-96231b3b80d8
When an overflow intrinsic is followed by a non-overflow instruction,
replace the latter with an extract. For example:
%sadd = tail call { i32, i1 } @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
%sadd3 = add i32 %a, %b
Here the add statement will be replaced by an extract.
When an overflow intrinsic follows a non-overflow instruction, a clone
of the intrinsic is inserted before the normal instruction, which makes
it the same as the previous case. Subsequent runs of GVN can then clean
up the duplicate instructions and insert the extract.
This fixes PR8817.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203553 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When the sample profiles include discriminator information,
use the discriminator values to distinguish instruction weights
in different basic blocks.
This modifies the BodySamples mapping to map <line, discriminator> pairs
to weights. Instructions on the same line but different blocks, will
use different discriminator values. This, in turn, means that the blocks
may have different weights.
Other changes in this patch:
- Add tests for positive values of line offset, discriminator and samples.
- Change data types from uint32_t to unsigned and int and do additional
validation.
Reviewers: chandlerc
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D2857
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203508 91177308-0d34-0410-b5e6-96231b3b80d8
This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
detail
2) Change it to actually be a *Use* iterator rather than a *User*
iterator.
3) Add an adaptor which is a User iterator that always looks through the
Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
they wanted a use_iterator (and to explicitly dig out the User when
needed), or a user_iterator which makes the Use itself totally
opaque.
Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.
The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.
However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]
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This compiles with no changes to clang/lld/lldb with MSVC and includes
overloads to various functions which are used by those projects and llvm
which have OwningPtr's as parameters. This should allow out of tree
projects some time to move. There are also no changes to libs/Target,
which should help out of tree targets have time to move, if necessary.
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to ensure we don't mess up any of the overrides. Necessary for cleaning
up the Value use iterators and enabling range-based traversing of use
lists.
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Move the test for this class into the IR unittests as well.
This uncovers that ValueMap too is in the IR library. Ironically, the
unittest for ValueMap is useless in the Support library (honestly, so
was the ValueHandle test) and so it already lives in the IR unittests.
Mmmm, tasty layering.
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name might indicate, it is an iterator over the types in an instruction
in the IR.... You see where this is going.
Another step of modularizing the support library.
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business.
This header includes Function and BasicBlock and directly uses the
interfaces of both classes. It has to do with the IR, it even has that
in the name. =] Put it in the library it belongs to.
This is one step toward making LLVM's Support library survive a C++
modules bootstrap.
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remove_if that its predicate is adaptable. We don't actually need this,
we can write a generic adapter for any predicate.
This lets us remove some very wrong std::function usages. We should
never be using std::function for predicates to algorithms. This incurs
an *indirect* call overhead for every evaluation of the predicate, and
makes it very hard to inline through.
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operand_values. The first provides a range view over operand Use
objects, and the second provides a range view over the Value*s being
used by those operands.
The naming is "STL-style" rather than "LLVM-style" because we have
historically named iterator methods STL-style, and range methods seem to
have far more in common with their iterator counterparts than with
"normal" APIs. Feel free to bikeshed on this one if you want, I'm happy
to change these around if people feel strongly.
I've switched code in SROA and LCG to exercise these mostly to ensure
they work correctly -- we don't really have an easy way to unittest this
and they're trivial.
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address spaces.
This isn't really a correctness issue (the values are truncated) but its
much cleaner.
Patch by Matt Arsenault!
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the default.
Based on the patch by Matt Arsenault, D1764!
I switched one place to use the more direct pointer type to compute the
desired address space, and I reworked the memcpy rewriting section to
reflect significant refactorings that this patch helped inspire.
Thanks to several of the folks who helped review and improve the patch
as well.
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to work independently for the slice side and the other side.
This allows us to only compute the minimum of the two when we actually
rewrite to a memcpy that needs to take the minimum, and preserve higher
alignment for one side or the other when rewriting to loads and stores.
This fix was inspired by seeing the result of some refactoring that
makes addrspace handling better.
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D1764, which in turn set off the other refactorings to make
'getSliceAlign()' a sensible thing.
There are two possible inputs to the required alignment of a memory
transfer intrinsic: the alignment constraints of the source and the
destination. If we are *only* introducing a (potentially new) offset
onto one side of the transfer, we don't need to consider the alignment
constraints of the other side. Use this to simplify the logic feeding
into alignment computation for unsplit transfers.
Also, hoist the clamp of the magical zero alignment for these intrinsics
to the more customary one alignment early. This lets several other
conditions melt away.
No functionality changed. There is a further improvement this exposes
which *will* change functionality, but that's arriving in a separate
patch.
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rewriting logic: don't pass custom offsets for the adjusted pointer to
the new alloca.
We always passed NewBeginOffset here. Sometimes we spelled it
BeginOffset, but only when they were in fact equal. Whats worse, the API
is set up so that you can't reasonably call it with anything else -- it
assumes that you're passing it an offset relative to the *original*
alloca that happens to fall within the new one. That's the whole point
of NewBeginOffset, it's the clamped beginning offset.
No functionality changed.
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alignment of the slice being rewritten, not any arbitrary offset.
Every caller is really just trying to compute the alignment for the
whole slice, never for some arbitrary alignment. They are also just
passing a type when they have one to see if we can skip an explicit
alignment in the IR by using the type's alignment. This makes for a much
simpler interface.
Another refactoring inspired by the addrspace patch for SROA, although
only loosely related.
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consistency with memcpy rewriting, and fix a latent bug in the alignment
management for memset.
The alignment issue is that getAdjustedAllocaPtr is computing the
*relative* offset into the new alloca, but the alignment isn't being set
to the relative offset, it was using the the absolute offset which is
into the old alloca.
I don't think its possible to write a test case that actually reaches
this code where the resulting alignment would be observably different,
but the intent was clearly to use the relative offset within the new
alloca.
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rather than passing them as arguments.
While I generally prefer actual arguments, in this case the readability
loss is substantial. By using members we avoid repeatedly calculating
the offsets, and once we're using members it is useful to ensure that
those names *always* refer to the original-alloca-relative new offset
for a rewritten slice.
No functionality changed. Follow-up refactoring, all toward getting the
address space patch merged.
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slice being rewritten.
We had the same code scattered across most of the visits. Instead,
compute the new offsets and the slice size once when we start to visit
a particular slice, and use the member variables from then on. This
reduces quite a bit of code duplication.
No functionality changed. Refactoring inspired to make it easier to
apply the address space patch to SROA.
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checking in SROA.
The primary change is to just rely on uge for checking that the offset
is within the allocation size. This removes the explicit checks against
isNegative which were terribly error prone (including the reversed logic
that led to PR18615) and prevented us from supporting stack allocations
larger than half the address space.... Ok, so maybe the latter isn't
*common* but it's a silly restriction to have.
Also, we used to try to support a PHI node which loaded from before the
start of the allocation if any of the loaded bytes were within the
allocation. This doesn't make any sense, we have never really supported
loading or storing *before* the allocation starts. The simplified logic
just doesn't care.
We continue to allow loading past the end of the allocation in part to
support cases where there is a PHI and some loads are larger than others
and the larger ones reach past the end of the allocation. We could solve
this a different and more conservative way, but I'm still somewhat
paranoid about this.
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their inputs come from std::stable_sort and they are not total orders.
I'm not a huge fan of this, but the really bad std::stable_sort is right
at the beginning of Reassociate. After we commit to stable-sort based
consistent respect of source order, the downstream sorts shouldn't undo
that unless they have a total order or they are used in an
order-insensitive way. Neither appears to be true for these cases.
I don't have particularly good test cases, but this jumped out by
inspection when looking for output instability in this pass due to
changes in the ordering of std::sort.
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implemented this way a long time ago and due to the overwhelming bugs
that surfaced, moved to a much more relaxed variant. Richard Smith would
like to understand the magnitude of this problem and it seems fairly
harmless to keep some flag-controlled logic to get the extremely strict
behavior here. I'll remove it if it doesn't prove useful.
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Instead, have a DataLayoutPass that holds one. This will allow parts of LLVM
don't don't handle passes to also use DataLayout.
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just "load". This helps avoid pointless de-duping with order-sensitive
numbers as we already have unique names from the original load. It also
makes the resulting IR quite a bit easier to read.
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the pointer adjustment code. This is the primary code path that creates
totally new instructions in SROA and being able to lump them based on
the pointer value's name for which they were created causes
*significantly* fewer name collisions and general noise in the debug
output. This is particularly significant because it is making it much
harder to track down instability in the output of SROA, as name
de-duplication is a totally harmless form of instability that gets in
the way of seeing real problems.
The new fancy naming scheme tries to dig out the root "pre-SROA" name
for pointer values and associate that all the way through the pointer
formation instructions. Digging out the root is important to prevent the
multiple iterative rounds of SROA from just layering too much cruft on
top of cruft here. We already track the layers of SROAs iteration in the
alloca name prefix. We don't need to duplicate it here.
Should have no functionality change, and shouldn't have any really
measurable impact on NDEBUG builds, as most of the complex logic is
debug-only.
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using OldPtr more heavily. Lots of this code was written before the
rewriter had an OldPtr member setup ahead of time. There are already
asserts in place that should ensure this doesn't change any
functionality.
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the break statement, not just think it to yourself....
No idea how this worked at all, much less survived most bots, my
bootstrap, and some bot bootstraps!
The Polly one didn't survive, and this was filed as PR18959. I don't
have a reduced test case and honestly I'm not seeing the need. What we
probably need here are better asserts / debug-build behavior in
SmallPtrSet so that this madness doesn't make it so far.
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sorting it. This helps uncover latent reliance on the original ordering
which aren't guaranteed to be preserved by std::sort (but often are),
and which are based on the use-def chain orderings which also aren't
(technically) guaranteed.
Only available in C++11 debug builds, and behind a flag to prevent noise
at the moment, but this is generally useful so figured I'd put it in the
tree rather than keeping it out-of-tree.
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the destination operand or source operand of a memmove.
It so happens that it was impossible for SROA to try to rewrite
self-memmove where the operands are *identical*, because either such
a think is volatile (and we don't rewrite) or it is non-volatile, and we
don't even register it as a use of the alloca.
However, making the 'IsDest' test *rely* on this subtle fact is... Very
confusing for the reader. We should use the direct and readily available
test of the Use* which gives us concrete information about which operand
is being rewritten.
No functionality changed, I hope! ;]
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ordering.
The fundamental problem that we're hitting here is that the use-def
chain ordering is *itself* not a stable thing to be relying on in the
rewriting for SROA. Further, we use a non-stable sort over the slices to
arrange them based on the section of the alloca they're operating on.
With a debugging STL implementation (or different implementations in
stage2 and stage3) this can cause stage2 != stage3.
The specific aspect of this problem fixed in this commit deals with the
rewriting and load-speculation around PHIs and Selects. This, like many
other aspects of the use-rewriting in SROA, is really part of the
"strong SSA-formation" that is doen by SROA where it works very hard to
canonicalize loads and stores in *just* the right way to satisfy the
needs of mem2reg[1]. When we have a select (or a PHI) with 2 uses of the
same alloca, we test that loads downstream of the select are
speculatable around it twice. If only one of the operands to the select
needs to be rewritten, then if we get lucky we rewrite that one first
and the select is immediately speculatable. This can cause the order of
operand visitation, and thus the order of slices to be rewritten, to
change an alloca from promotable to non-promotable and vice versa.
The fix is to defer all of the speculation until *after* the rewrite
phase is done. Once we've rewritten everything, we can accurately test
for whether speculation will work (once, instead of twice!) and the
order ceases to matter.
This also happens to simplify the other subtlety of speculation -- we
need to *not* speculate anything unless the result of speculating will
make the alloca fully promotable by mem2reg. I had a previous attempt at
simplifying this, but it was still pretty horrible.
There is actually already a *really* nice test case for this in
basictest.ll, but on multiple STL implementations and inputs, we just
got "lucky". Fortunately, the test case is very small and we can
essentially build it in exactly the opposite way to get reasonable
coverage in both directions even from normal STL implementations.
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CodeGenPrepare uses extensively TargetLowering which is part of libLLVMCodeGen.
This is a layer violation which would introduce eventually a dependence on
CodeGen in ScalarOpts.
Move CodeGenPrepare into libLLVMCodeGen to avoid that.
Follow-up of <rdar://problem/15519855>
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I am really sorry for the noise, but the current state where some parts of the
code use TD (from the old name: TargetData) and other parts use DL makes it
hard to write a patch that changes where those variables come from and how
they are passed along.
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On x86, shifting a vector by a scalar is significantly cheaper than shifting a
vector by another fully general vector. Unfortunately, because SelectionDAG
operates on just one basic block at a time, the shufflevector instruction that
reveals whether the right-hand side of a shift *is* really a scalar is often
not visible to CodeGen when it's needed.
This adds another handler to CodeGenPrepare, to sink any useful shufflevector
instructions down to the basic block where they're used, predicated on a target
hook (since on other architectures, doing so will often just introduce extra
real work).
rdar://problem/16063505
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Fixes PR18753 and PR18782.
This is necessary for LICM to preserve LCSSA correctly and efficiently.
There is still some active discussion about whether we should be using
LCSSA, but we can't just immediately stop using it and we *need* LICM to
preserve it while we are using it. We can restore the old SSAUpdater
driven code if and when there is a serious effort to remove the reliance
on LCSSA from all of the loop passes.
However, this also serves as a great example of why LCSSA is very nice
to have. This change significantly simplifies the process of sinking
instructions for LICM, and makes it quite a bit less expensive.
It wouldn't even be as complex as it is except that I had to start the
process of removing the big recursive LCSSA formation hammer in order to
switch even this much of the re-forming code to asserting that LCSSA was
preserved. I'll fully remove that next just to tidy things up until the
LCSSA debate settles one way or the other.
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The addressing mode matcher checks at some point the profitability of folding an
instruction into the addressing mode. When the instruction to be folded has
several uses, it checks that the instruction can be folded in each use.
To do so, it creates a new matcher for each use and check if the instruction is
in the list of the matched instructions of this new matcher.
The new matchers may promote some instructions and this has to be undone to keep
the state of the original matcher consistent.
A test case will follow.
<rdar://problem/16020230>
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The bitcast instruction during constant materialization was not placed correcly
in the presence of phi nodes. This commit fixes the insertion point to be in the
idom instead.
This fixes PR18768
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This fix first traverses the whole use list of the constant expression and
keeps track of the instructions that need to be updated. Then perform the
fixup afterwards.
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mode.
Basically the idea is to transform code like this:
%idx = add nsw i32 %a, 1
%sextidx = sext i32 %idx to i64
%gep = gep i8* %myArray, i64 %sextidx
load i8* %gep
Into:
%sexta = sext i32 %a to i64
%idx = add nsw i64 %sexta, 1
%gep = gep i8* %myArray, i64 %idx
load i8* %gep
That way the computation can be folded into the addressing mode.
This transformation is done as part of the addressing mode matcher.
If the matching fails (not profitable, addressing mode not legal, etc.), the
matcher will revert the related promotions.
<rdar://problem/15519855>
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Ideally only those transform passes that run at -O0 remain enabled,
in reality we get as close as we reasonably can.
Passes are responsible for disabling themselves, it's not the job of
the pass manager to do it for them.
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No functional change. Updated loops from:
for (I = scc_begin(), E = scc_end(); I != E; ++I)
to:
for (I = scc_begin(); !I.isAtEnd(); ++I)
for teh win.
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LCSSA when we promote to SSA registers inside of LICM.
Currently, this is actually necessary. The promotion logic in LICM uses
SSAUpdater which doesn't understand how to place LCSSA PHI nodes.
Teaching it to do so would be a very significant undertaking. It may be
worthwhile and I've left a FIXME about this in the code as well as
starting a thread on llvmdev to try to figure out the right long-term
solution.
For now, the PR needs to be fixed. Short of using the promition
SSAUpdater to place both the LCSSA PHI nodes and the promoted PHI nodes,
I don't see a cleaner or cheaper way of achieving this. Fortunately,
LCSSA is relatively lazy and sparse -- it should only update
instructions which need it. We can also skip the recursive variant when
we don't promote to SSA values.
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preserve loop simplify of enclosing loops.
The problem here starts with LoopRotation which ends up cloning code out
of the latch into the new preheader it is buidling. This can create
a new edge from the preheader into the exit block of the loop which
breaks LoopSimplify form. The code tries to fix this by splitting the
critical edge between the latch and the exit block to get a new exit
block that only the latch dominates. This sadly isn't sufficient.
The exit block may be an exit block for multiple nested loops. When we
clone an edge from the latch of the inner loop to the new preheader
being built in the outer loop, we create an exiting edge from the outer
loop to this exit block. Despite breaking the LoopSimplify form for the
inner loop, this is fine for the outer loop. However, when we split the
edge from the inner loop to the exit block, we create a new block which
is in neither the inner nor outer loop as the new exit block. This is
a predecessor to the old exit block, and so the split itself takes the
outer loop out of LoopSimplify form. We need to split every edge
entering the exit block from inside a loop nested more deeply than the
exit block in order to preserve all of the loop simplify constraints.
Once we try to do that, a problem with splitting critical edges
surfaces. Previously, we tried a very brute force to update LoopSimplify
form by re-computing it for all exit blocks. We don't need to do this,
and doing this much will sometimes but not always overlap with the
LoopRotate bug fix. Instead, the code needs to specifically handle the
cases which can start to violate LoopSimplify -- they aren't that
common. We need to see if the destination of the split edge was a loop
exit block in simplified form for the loop of the source of the edge.
For this to be true, all the predecessors need to be in the exact same
loop as the source of the edge being split. If the dest block was
originally in this form, we have to split all of the deges back into
this loop to recover it. The old mechanism of doing this was
conservatively correct because at least *one* of the exiting blocks it
rewrote was the DestBB and so the DestBB's predecessors were fixed. But
this is a much more targeted way of doing it. Making it targeted is
important, because ballooning the set of edges touched prevents
LoopRotate from being able to split edges *it* needs to split to
preserve loop simplify in a coherent way -- the critical edge splitting
would sometimes find the other edges in need of splitting but not
others.
Many, *many* thanks for help from Nick reducing these test cases
mightily. And helping lots with the analysis here as this one was quite
tricky to track down.
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because of the inside-out run of LoopSimplify in the LoopPassManager and
the fact that LoopSimplify couldn't be "preserved" across two
independent LoopPassManagers.
Anyways, in that case, IndVars wasn't correctly preserving an LCSSA PHI
node because it thought it was rewriting (via SCEV) the incoming value
to a loop invariant value. While it may well be invariant for the
current loop, it may be rewritten in terms of an enclosing loop's
values. This in and of itself is fine, as the LCSSA PHI node in the
enclosing loop for the inner loop value we're rewriting will have its
own LCSSA PHI node if used outside of the enclosing loop. With me so
far?
Well, the current loop and the enclosing loop may share an exiting
block and exit block, and when they do they also share LCSSA PHI nodes.
In this case, its not valid to RAUW through the LCSSA PHI node.
Expected crazy test included.
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Summary:
I searched Transforms/ and Analysis/ for 'ByVal' and updated those call
sites to check for inalloca if appropriate.
I added tests for any change that would allow an optimization to fire on
inalloca.
Reviewers: nlewycky
Differential Revision: http://llvm-reviews.chandlerc.com/D2449
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the loops in a function, and teach LICM to work in the presance of
LCSSA.
Previously, LCSSA was a loop pass. That made passes requiring it also be
loop passes and unable to depend on function analysis passes easily. It
also caused outer loops to have a different "canonical" form from inner
loops during analysis. Instead, we go into LCSSA form and preserve it
through the loop pass manager run.
Note that this has the same problem as LoopSimplify that prevents
enabling its verification -- loop passes which run at the end of the loop
pass manager and don't preserve these are valid, but the subsequent loop
pass runs of outer loops that do preserve this pass trigger too much
verification and fail because the inner loop no longer verifies.
The other problem this exposed is that LICM was completely unable to
handle LCSSA form. It didn't preserve it and it actually would give up
on moving instructions in many cases when they were used by an LCSSA phi
node. I've taught LICM to support detecting LCSSA-form PHI nodes and to
hoist and sink around them. This may actually let LICM fire
significantly more because we put everything into LCSSA form to rotate
the loop before running LICM. =/ Now LICM should handle that fine and
preserve it correctly. The down side is that LICM has to require LCSSA
in order to preserve it. This is just a fact of life for LCSSA. It's
entirely possible we should completely remove LCSSA from the optimizer.
The test updates are essentially accomodating LCSSA phi nodes in the
output of LICM, and the fact that we now completely sink every
instruction in ashr-crash below the loop bodies prior to unrolling.
With this change, LCSSA is computed only three times in the pass
pipeline. One of them could be removed (and potentially a SCEV run and
a separate LoopPassManager entirely!) if we had a LoopPass variant of
InstCombine that ran InstCombine on the loop body but refused to combine
away LCSSA PHI nodes. Currently, this also prevents loop unrolling from
being in the same loop pass manager is rotate, LICM, and unswitch.
There is one thing that I *really* don't like -- preserving LCSSA in
LICM is quite expensive. We end up having to re-run LCSSA twice for some
loops after LICM runs because LICM can undo LCSSA both in the current
loop and the parent loop. I don't really see good solutions to this
other than to completely move away from LCSSA and using tools like
SSAUpdater instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200067 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r200058 and adds the using directive for
ARMTargetTransformInfo to silence two g++ overload warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200062 91177308-0d34-0410-b5e6-96231b3b80d8
This commit caused -Woverloaded-virtual warnings. The two new
TargetTransformInfo::getIntImmCost functions were only added to the superclass,
and to the X86 subclass. The other targets were not updated, and the
warning highlighted this by pointing out that e.g. ARMTTI::getIntImmCost was
hiding the two new getIntImmCost variants.
We could pacify the warning by adding "using TargetTransformInfo::getIntImmCost"
to the various subclasses, or turning it off, but I suspect that it's wrong to
leave the functions unimplemnted in those targets. The default implementations
return TCC_Free, which I don't think is right e.g. for ARM.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200058 91177308-0d34-0410-b5e6-96231b3b80d8
