This is D77454, except for stores.  All the infrastructure work was done
for loads, so the remaining changes necessary are relatively small.

Differential Revision: https://reviews.llvm.org/D79968

This has been duplicated since before
2372a193, but that commit has it
appearing twice in the space of 10 lines of the same function body. It
could also be hoisted up to the point just after where the last
special-case is considered, but I want to keep the intent of the
original authors.

Committed as obvious without a review.

The "null-pointer-is-valid" attribute needs to be checked by many
pointer-related combines. To make the check more efficient, convert
it from a string into an enum attribute.

In the future, this attribute may be replaced with data layout
properties.

Differential Revision: https://reviews.llvm.org/D78862

Summary:
This change exposes the vector name mangling with LLVM ISA (used as part
of vector-function-abi-variant) as a utility.
This can then be used by front-ends that add this attribute.
Note that all parameters passed in to the function will be mangled with
the "v" token to identify that they are of of vector type. So, it is the
responsibility of the caller to confirm that all parameters in the
vectorized variant is of vector type.

Added unit test to show vector name mangling.

Reviewed-By: fpetrogalli, simoll

Differential Revision: https://reviews.llvm.org/D79867

Add -tsan-instrument-read-before-write which allows instrumenting reads
of reads-before-writes.

This is required for KCSAN [1], where under certain configurations plain
writes behave differently (e.g. aligned writes up to word size may be
treated as atomic). In order to avoid missing potential data races due
to plain RMW operations ("x++" etc.), we will require instrumenting
reads of reads-before-writes.

[1] https://github.com/google/ktsan/wiki/KCSAN

Author: melver (Marco Elver)
Reviewed-in: https://reviews.llvm.org/D79983

This reverts commit 767db5be.

Summary:
Replacing uses of std::function pointers or refs, or Optional, to
function_ref, since the usage pattern allows that. If the function is
optional, using a default parameter value (nullptr). This led to a few
parameter reshufles, to push all optionals to the end of the parameter
list.

Reviewers: davidxl, dblaikie

Subscribers: arsenm, jvesely, nhaehnle, eraman, hiraditya, haicheng, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79917

It's really almost going to be misleading, see the example in
https://bugs.llvm.org/show_bug.cgi?id=45820

Maybe at some point we can do something fancier, but at least
this will fix a bug where we step on dead code while debugging.

The fact that loads and stores can have the alignment missing is a
constant source of confusion: code that usually works can break down in
rare cases.  So fix the LoadInst API so the alignment is never missing.

To reduce the number of changes required to make this work, IRBuilder
and certain LoadInst constructors will grab the module's datalayout and
compute the alignment automatically.  This is the same alignment
instcombine would eventually apply anyway; we're just doing it earlier.
There's a minor risk that the way we're retrieving the datalayout
could break out-of-tree code, but I don't think that's likely.

This is the last in a series of patches, so most of the necessary
changes have already been merged.

Differential Revision: https://reviews.llvm.org/D77454

This is relanding of rGbb308b020522420413c7d3f2989a88f2fc423c56 after
speculatively fixing buildbot lit test failure which was seen on two
bots (I cannot reproduce the lit test failure locally either).

[RS4GC] Fix algorithm to avoid setting vector BDV for scalar derived
pointer

Summary:
This is a more general fix to 59029b9e (D75704).
This patch does the following:

updates isKnownBaseValue to account for base pointer and
derived pointer having differing types.

This inturn allows us to populate the
lattice (States) for such derived pointers.

It also updates all states where the base and derived pointers have
differing types (vector versus scalar) and conservatively marks these
states as conflictcs.
Note that in 59029b9e, we were just fixing existing lattice values
and that too, only for uses of extractelement.

Reviewers: reames, skatkov, dantrushin

Reviewed By: skatkov

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D76305

This reverts commit 897d8ee5,
due to causing an infinite loop when encountering a loop with
a sub-region with an inner loop.

This reverts commit bb308b02.
Failing a testcase.

Summary:
This is a more general fix to 59029b9e (D75704).
This patch does the following:
1. updates isKnownBaseValue to account for base pointer and
derived pointer having differing types.
2. This inturn allows us to populate the
lattice (States) for such derived pointers.
3. It also updates all states where the base and derived pointers have
differing types (vector versus scalar) and conservatively marks these
states as conflictcs.
Note that in 59029b9e, we were just fixing existing lattice values
and that too, only for uses of extractelement.

Reviewers: reames, skatkov, dantrushin

Reviewed By: skatkov

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76305

The patch standardizes printing of VPRecipes a bit, by hoisting out the
common emission of \\l\"+\n. It simplifies the code and is also a first
step towards untangling printing from DOT format output, with the goal
of making the DOT output optional and to provide a more concise debug
output if DOT output is disabled.

Reviewers: gilr, Ayal, rengolin

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D78883

This patch introduces an improvement in the Alignment of the loads
generated in createReplacementValues() by querying AAAlign attribute for
the best Alignment for the base.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D76550

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D76208

Summary:

This change introduces InliningAdvisor (and related APIs), the interface
that abstracts decision making away from the inlining pass. We will use
this interface to delegate decision making to a trained ML model,
subsequently (see referenced RFC).

RFC: http://lists.llvm.org/pipermail/llvm-dev/2020-April/140763.html

Reviewers: davidxl, eraman, dblaikie

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79042

Summary:
Analyses that are statefull should not be retrieved through a proxy from
an outer IR unit, as these analyses are only invalidated at the end of
the inner IR unit manager.
This patch disallows getting the outer manager and provides an API to
get a cached analysis through the proxy. If the analysis is not
stateless, the call to getCachedResult will assert.

Reviewers: chandlerc

Subscribers: mehdi_amini, eraman, hiraditya, zzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72893

Summary:
Update check to include the check for unreachable.

Basic blocks ending in unreachable are special cased, as these blocks may be already unswitched. Before this patch this check is only done for the default destination.
The condition for the exit cases and the default case must be the same, because we should never leave edges from the switch instruction to a basic block that we are unswitching. In PR45355 we still have a remaining edge (that we're attempting to remove from the DT) because its the default edge to an unreachable-terminated block where we unswitch a case edge to that block.

Resolves PR45355.

Reviewers: chandlerc

Subscribers: hiraditya, uabelho, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78279

Use Align instead of using MaybeAlign; all the operations in question
have known alignment.

For getSliceAlign() in particular, in the cases where we used to return
None, it would be converted back to an Align by IRBuilder, so there's no
functional change there.

Split off from D77454.

Differential Revision: https://reviews.llvm.org/D79205

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D79359

This reverts commit eef95f27.

The new assertion about branch propability sums does not hold.

This patch adds a new TTI hook to allow targets to tell LSR that
a chain including some instruction is already profitable and
should not be optimized. This patch also adds an implementation
of this TTI hook for ARM so LSR doesn't optimize chains that include
the VCTP intrinsic.

Differential Revision: https://reviews.llvm.org/D79418

This was reverted because of a miscompilation. At closer inspection, the
problem was actually visible in a changed llvm regression test too. This
one-line follow up fix/recommit will splat the IV, which is what we are trying
to avoid if unnecessary in general, if tail-folding is requested even if all
users are scalar instructions after vectorisation. Because with tail-folding,
the splat IV will be used by the predicate of the masked loads/stores
instructions. The previous version omitted this, which caused the
miscompilation. The original commit message was:

If tail-folding of the scalar remainder loop is applied, the primary induction
variable is splat to a vector and used by the masked load/store vector
instructions, thus the IV does not remain scalar. Because we now mark
that the IV does not remain scalar for these cases, we don't emit the vector IV
if it is not used. Thus, the vectoriser produces less dead code.

Thanks to Ayal Zaks for the direction how to fix this.

This is a reimplementation of the `orderNodes` function, as the old
implementation didn't take into account all cases.

Fix PR41509

Differential Revision: https://reviews.llvm.org/D79037

Hide the method that allows setting probability for particular
edge and introduce a public method that sets probabilities for
all outgoing edges at once.
Setting individual edge probability is error prone. More over
it is difficult to check that the total probability is 1.0
because there is no easy way to know when the user finished
setting all the probabilities.

Reviewers: yamauchi, ebrevnov
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79396

Fixes PR41696

The loop-reroll pass generates an invalid IR (or its assertion
fails in debug build) if values of the base instruction and
other root instructions (terms used in the loop-reroll pass)
are used outside the loop block. See IRs written in PR41696
as examples.

The current implementation of the loop-reroll pass can reroll
only loops that don't have values that are used outside the
loop, except reduced values (the last values of reduction chains).
This is described in the comment of the `LoopReroll::reroll`
function.
https://github.com/llvm/llvm-project/blob/llvmorg-10.0.0/llvm/lib/Transforms/Scalar/LoopRerollPass.cpp#L1600

This is checked in the `LoopReroll::DAGRootTracker::validate`
function.
https://github.com/llvm/llvm-project/blob/llvmorg-10.0.0/llvm/lib/Transforms/Scalar/LoopRerollPass.cpp#L1393

However, the base instruction and other root instructions skip
this check in the validation loop.
https://github.com/llvm/llvm-project/blob/llvmorg-10.0.0/llvm/lib/Transforms/Scalar/LoopRerollPass.cpp#L1229

Moving the check in front of the skip is the logically simplest
fix. However, inserting the check in an earlier stage is better
in terms of compilation time of unrerollable loops. This fix
inserts the check for the base instruction into the function
to validate possible base/root instructions. Check for other
root instructions is unnecessary because they don't match any
base instructions if they have uses outside the loop.

Differential Revision: https://reviews.llvm.org/D79549

For AAReturnedValues we treated new and existing information differently
in the updateImpl. Only the latter was properly analyzed and
categorized. The former was thought to be analyzed in the subsequent
update. Since the Attributor does not support "self-updates" we need to
make sure the state is "stable" after each updateImpl invocation. That
is, if the surrounding information does not change, the state is valid.
Now we make sure all return values have been handled and properly
categorized each iteration. We might not update again if we have not
requested a non-fix attribute so we cannot "wait" for the next update to
analyze a new return value.

Bug reported by @sdmitriev.

We want to add a way to avoid merging identical calls so as to keep the
separate debug-information for those calls. There is also an asan
usecase where having this attribute would be beneficial to avoid
alternative work-arounds.

Here is the link to the feature request:
https://bugs.llvm.org/show_bug.cgi?id=42783.

`nomerge` is different from `noline`. `noinline` prevents function from
inlining at callsites, but `nomerge` prevents multiple identical calls
from being merged into one.

This patch adds `nomerge` to disable the optimization in IR level. A
followup patch will be needed to let backend understands `nomerge` and
avoid tail merge at backend.

Reviewed By: asbirlea, rnk

Differential Revision: https://reviews.llvm.org/D78659

Reviewers: jdoerfert, sstefan1, uenoku

Reviewed By: jdoerfert

Subscribers: hiraditya, uenoku, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79801

Summary:
This patch makes propagatesPoison be more accurate by returning true on
more bin ops/unary ops/casts/etc.

The changed test in ScalarEvolution/nsw.ll was introduced by
https://github.com/llvm/llvm-project/commit/a19edc4d15b0dae0210b90615775edd76f021008 .
IIUC, the goal of the tests is to show that iv.inc's SCEV expression still has
no-overflow flags even if the loop isn't in the wanted form.
It becomes more accurate with this patch, so think this is okay.

Reviewers: spatel, lebedev.ri, jdoerfert, reames, nikic, sanjoy

Reviewed By: spatel, nikic

Subscribers: regehr, nlopes, efriedma, fhahn, javed.absar, llvm-commits, hiraditya

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78615

gcov 4.8 (r189778) moved the exit block from the last to the second.
The .gcda format is compatible with 4.7 but

* decoding libgcov 4.7 produced .gcda with gcov [4.7,8) can mistake the
  exit block, emit bogus `%s:'%s' has arcs from exit block\n` warnings,
  and print wrong `" returned %s` for branch statistics (-b).
* decoding libgcov 4.8 produced .gcda with gcov 4.7 has similar issues.

Also, rename "return block" to "exit block" because the latter is the
appropriate term.

We will now ensure ensure the return type of called function is the type
of all call sites we are going to rewrite. This avoids a problem
partially fixed by D79680. The part that was not covered is a use of
this "weird" casted call site (see `@func3` in `misc_crash.ll`).

misc_crash.ll checks are auto-generated now.

We should never give up on AAIsDead as it guards other AAs from
unreachable code (in which SSA properties are meaningless). We did
however use required dependences on some queries in AAIsDead which
caused us to invalidate AAIsDead if the queried AA got invalidated.
We now use optional dependences instead. The bug that exposed this is
added to the liveness.ll test and other test changes show the impact.

Bug report by @sdmitriev.

During an update of AAIsDead, new instructions become live. If we query
information from them, the result is often just the initial state, e.g.,
for call site `noreturn` and `nounwind`. We will now trigger an update
for cached attributes during the AAIsDead update, though other AAs might
later use the same API.

Follow-up to D79452.
Mimics the extra use cost formula for the inverse transform with extracts.

Summary: Factoring out in preparation to https://reviews.llvm.org/D79042

Reviewers: dblaikie, davidxl

Subscribers: mgorny, eraman, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79613

Reviewers: jdoerfert, sstefan1, uenoku

Reviewed By: uenoku

Subscribers: hiraditya, uenoku, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79680