This is the last significant change suggested in PR37806:
https://bugs.llvm.org/show_bug.cgi?id=37806#c5
...though there are several follow-ups noted in the code comments
in this patch to complete this transform.
It's possible that a binop feeding a select-shuffle has been eliminated
by earlier transforms (or the code was just written like this in the 1st
place), so we'll fail to match the patterns that have 2 binops from:
D48401,
D48678,
D48662,
D48485.
In that case, we can try to materialize identity constants for the remaining
binop to fill in the "ghost" lanes of the vector (where we just want to pass
through the original values of the source operand).
I added comments to ConstantExpr::getBinOpIdentity() to show planned follow-ups.
For now, we only handle the 5 commutative integer binops (add/mul/and/or/xor).
Differential Revision: https://reviews.llvm.org/D48830
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336196 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When salvaging a dbg.declare/dbg.addr we should not add
DW_OP_stack_value to the DIExpression
(see test/Transforms/InstCombine/salvage-dbg-declare.ll).
Consider this example
%vla = alloca i32, i64 2
call void @llvm.dbg.declare(metadata i32* %vla, metadata !1, metadata !DIExpression())
Instcombine will turn it into
%vla1 = alloca [2 x i32]
%vla1.sub = getelementptr inbounds [2 x i32], [2 x i32]* %vla, i64 0, i64 0
call void @llvm.dbg.declare(metadata [2 x i32]* %vla1.sub, metadata !19, metadata !DIExpression())
If the GEP can be eliminated, then the dbg.declare will be salvaged
and we should get
%vla1 = alloca [2 x i32]
call void @llvm.dbg.declare(metadata [2 x i32]* %vla1, metadata !19, metadata !DIExpression())
The problem was that salvageDebugInfo did not recognize dbg.declare
as being indirect (%vla1 points to the value, it does not hold the
value), so we incorrectly got
call void @llvm.dbg.declare(metadata [2 x i32]* %vla1, metadata !19, metadata !DIExpression(DW_OP_stack_value))
I also made sure that llvm::salvageDebugInfo and
DIExpression::prependOpcodes do not add DW_OP_stack_value to
the DIExpression in case no new operands are added to the
DIExpression. That way we avoid to, unneccessarily, turn a
register location expression into an implicit location expression
in some situations (see test11 in test/Transforms/LICM/sinking.ll).
Reviewers: aprantl, vsk
Reviewed By: aprantl, vsk
Subscribers: JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D48837
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336191 91177308-0d34-0410-b5e6-96231b3b80d8
unswitching loops.
Original patch trying to address this was sent in D47624, but that
didn't quite handle things correctly. There are two key principles used
to select whether and how to invalidate SCEV-cached information about
loops:
1) We must invalidate any info SCEV has cached before unswitching as we
may change (or destroy) the loop structure by the act of unswitching,
and make it hard to recover everything we want to invalidate within
SCEV.
2) We need to invalidate all of the loops whose CFGs are mutated by the
unswitching. Notably, this isn't the *entire* loop nest, this is
every loop contained by the outermost loop reached by an exit block
relevant to the unswitch.
And we need to do this even when doing trivial unswitching.
I've added more focused tests that directly check that SCEV starts off
with imprecise information and after unswitching (and simplifying
instructions) re-querying SCEV will produce precise information. These
tests also specifically work to check that an *outer* loop's information
becomes precise.
However, the testing here is still a bit imperfect. Crafting test cases
that reliably fail to be analyzed by SCEV before unswitching and succeed
afterward proved ... very, very hard. It took me several hours and
careful work to build these, and I'm not optimistic about necessarily
coming up with more to cover more elaborate possibilities. Fortunately,
the code pattern we are testing here in the pass is really
straightforward and reliable.
Thanks to Max Kazantsev for the initial work on this as well as the
review, and to Hal Finkel for helping me talk through approaches to test
this stuff even if it didn't come to much.
Differential Revision: https://reviews.llvm.org/D47624
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336183 91177308-0d34-0410-b5e6-96231b3b80d8
This patch changes order of transform in InstCombineCompares to avoid
performing transforms based on ranges which produce complex bit arithmetics
before more simple things (like folding with constants) are done. See PR37636
for the motivating example.
Differential Revision: https://reviews.llvm.org/D48584
Reviewed By: spatel, lebedev.ri
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336172 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Comment on Transforms/LoopVersioning/incorrect-phi.ll: With the change
SCEV is able to prove that the loop doesn't wrap-self (due to zext i16
to i64), disabling the entire loop versioning pass. Removed the zext and
just use i64.
Reviewers: sanjoy
Subscribers: jlebar, hiraditya, javed.absar, bixia, llvm-commits
Differential Revision: https://reviews.llvm.org/D48409
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336140 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: It is common to have the following min/max pattern during the intermediate stages of SLP since we only optimize at the end. This patch tries to catch such patterns and allow more vectorization.
%1 = extractelement <2 x i32> %a, i32 0
%2 = extractelement <2 x i32> %a, i32 1
%cond = icmp sgt i32 %1, %2
%3 = extractelement <2 x i32> %a, i32 0
%4 = extractelement <2 x i32> %a, i32 1
%select = select i1 %cond, i32 %3, i32 %4
Author: FarhanaAleen
Reviewed By: ABataev, RKSimon, spatel
Differential Revision: https://reviews.llvm.org/D47608
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336130 91177308-0d34-0410-b5e6-96231b3b80d8
This extends D48485 to allow another pair of binops (add/or) to be combined either
with or without a leading shuffle:
or X, C --> add X, C (when X and C have no common bits set)
Here, we need value tracking to determine that the 'or' can be reversed into an 'add',
and we've added general infrastructure to allow extending to other opcodes or moving
to where other passes could use that functionality.
Differential Revision: https://reviews.llvm.org/D48662
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336128 91177308-0d34-0410-b5e6-96231b3b80d8
Alternate opcode handling only supports binary operators, these tests demonstrate a missed opportunity to vectorize ceil/floor calls
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336125 91177308-0d34-0410-b5e6-96231b3b80d8
Due to current limitations in constant analysis, we need flags
on add or mul to show propagation for the potential transform
suggested in these tests (no other binops currently report
identity constants).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336101 91177308-0d34-0410-b5e6-96231b3b80d8
This version contains a fix to add values for which the state in ParamState change
to the worklist if the state in ValueState did not change. To avoid adding the
same value multiple times, mergeInValue returns true, if it added the value to
the worklist. The value is added to the worklist depending on its state in
ValueState.
Original message:
For comparisons with parameters, we can use the ParamState lattice
elements which also provide constant range information. This improves
the code for PR33253 further and gets us closer to use
ValueLatticeElement for all values.
Also, as we are using the range information in the solver directly, we
do not need tryToReplaceWithConstantRange afterwards anymore.
Reviewers: dberlin, mssimpso, davide, efriedma
Reviewed By: mssimpso
Differential Revision: https://reviews.llvm.org/D43762
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336098 91177308-0d34-0410-b5e6-96231b3b80d8
We were always using the opcodes of the first 2 scalars for the costs of the alternate opcode + shuffle. This made sense when we used SK_Alternate and opcodes were guaranteed to be alternating, but this fails for the more general SK_Select case.
This fix exposes an issue demonstrated by the fmul_fdiv_v4f32_const test - the SLM model has v4f32 fdiv costs which are more than twice those of the f32 scalar cost, meaning that the cost model determines that the vectorization is not performant. Unfortunately it completely ignores the fact that the fdiv by a constant will be changed into a fmul by InstCombine for a much lower cost vectorization. But at least we're seeing this now...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336095 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch introduce new intrinsic -
strip.invariant.group that was described in the
RFC: Devirtualization v2
Reviewers: rsmith, hfinkel, nlopes, sanjoy, amharc, kuhar
Subscribers: arsenm, nhaehnle, JDevlieghere, hiraditya, xbolva00, llvm-commits
Differential Revision: https://reviews.llvm.org/D47103
Co-authored-by: Krzysztof Pszeniczny <krzysztof.pszeniczny@gmail.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336073 91177308-0d34-0410-b5e6-96231b3b80d8
This is a simple implementation of the unroll-and-jam classical loop
optimisation.
The basic idea is that we take an outer loop of the form:
for i..
ForeBlocks(i)
for j..
SubLoopBlocks(i, j)
AftBlocks(i)
Instead of doing normal inner or outer unrolling, we unroll as follows:
for i... i+=2
ForeBlocks(i)
ForeBlocks(i+1)
for j..
SubLoopBlocks(i, j)
SubLoopBlocks(i+1, j)
AftBlocks(i)
AftBlocks(i+1)
Remainder Loop
So we have unrolled the outer loop, then jammed the two inner loops into
one. This can lead to a simpler inner loop if memory accesses can be shared
between the now jammed loops.
To do this we have to prove that this is all safe, both for the memory
accesses (using dependence analysis) and that ForeBlocks(i+1) can move before
AftBlocks(i) and SubLoopBlocks(i, j).
Differential Revision: https://reviews.llvm.org/D41953
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336062 91177308-0d34-0410-b5e6-96231b3b80d8
Alternate opcode handling only supports binary operators, these tests demonstrate missed opportunities to vectorize some sitofp/uitofp and fptosi/fptoui style casts as well as some (successful) float bits manipulations
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336060 91177308-0d34-0410-b5e6-96231b3b80d8
The mul+shl tests add coverage for the fold enabled with D48678.
The and+or tests are not handled yet; that's D48662.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335984 91177308-0d34-0410-b5e6-96231b3b80d8
This was discussed in D48401 as another improvement for:
https://bugs.llvm.org/show_bug.cgi?id=37806
If we have 2 different variable values, then we shuffle (select) those lanes,
shuffle (select) the constants, and then perform the binop. This eliminates a binop.
The new shuffle uses the same shuffle mask as the existing shuffle, so there's no
danger of creating a difficult shuffle.
All of the earlier constraints still apply, but we also check for extra uses to
avoid creating more instructions than we'll remove.
Additionally, we're disallowing the fold for div/rem because that could expose a
UB hole.
Differential Revision: https://reviews.llvm.org/D48678
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335974 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
An alternative to D48597.
Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=37936 | PR37936 ]].
The problem is as follows:
1. `indvars` marks `%dec` as `NUW`.
2. `loop-instsimplify` runs `instsimplify`, which constant-folds `%dec` to -1 (D47908)
3. `loop-reduce` tries to do some further modification, but crashes
with an type assertion in cast, because `%dec` is no longer an `Instruction`,
If the runline is split into two, i.e. you first run `-indvars -loop-instsimplify`,
store that into a file, and then run `-loop-reduce`, there is no crash.
So it looks like the problem is due to `-loop-instsimplify` not discarding SCEV.
But in this case we can just not crash if it's not an `Instruction`.
This is just a local fix, unlike D48597, so there may very well be other problems.
Reviewers: mkazantsev, uabelho, sanjoy, silviu.baranga, wmi
Reviewed By: mkazantsev
Subscribers: evstupac, javed.absar, spatel, llvm-commits
Differential Revision: https://reviews.llvm.org/D48599
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335950 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The InlinerFunctionImportStats will collect and dump stats regarding how
many function inlined into the module were imported by ThinLTO.
Reviewers: wmi, dexonsmith
Subscribers: mehdi_amini, inglorion, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D48729
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335914 91177308-0d34-0410-b5e6-96231b3b80d8
This is an enhancement to D48401 that was discussed in:
https://bugs.llvm.org/show_bug.cgi?id=37806
We can convert a shift-left-by-constant into a multiply (we canonicalize IR in the other
direction because that's generally better of course). This allows us to remove the shuffle
as we do in the regular opcodes-are-the-same cases.
This requires a small hack to make sure we don't introduce any extra poison:
https://rise4fun.com/Alive/ZGv
Other examples of opcodes where this would work are add+sub and fadd+fsub, but we already
canonicalize those subs into adds, so there's nothing to do for those cases AFAICT. There
are planned enhancements for opcode transforms such or -> add.
Note that there's a different fold needed if we've already managed to simplify away a binop
as seen in the test based on PR37806, but we manage to get that one case here because this
fold is positioned above the demanded elements fold currently.
Differential Revision: https://reviews.llvm.org/D48485
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335888 91177308-0d34-0410-b5e6-96231b3b80d8
If a trunc has a user in a block which is not reachable from entry,
we can safely perform trunc elimination as if this user didn't exist.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335816 91177308-0d34-0410-b5e6-96231b3b80d8
I think the intrinsics named 'avx512.mask.' should refer to the previous behavior of taking a mask argument in the intrinsic instead of using a 'select' or 'and' instruction in IR to accomplish the masking. This is more consistent with the goal that eventually we will have no intrinsics that have masking builtin. When we reach that goal, we should have no intrinsics named "avx512.mask".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335744 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds a custom trunc store lowering for v4i8 vector types.
Since there is not v.4b register, the v4i8 is promoted to v4i16 (v.4h)
and default action for v4i8 is to extract each element and issue 4
byte stores.
A better strategy would be to extended the promoted v4i16 to v8i16
(with undef elements) and extract and store the word lane which
represents the v4i8 subvectores. The construction:
define void @foo(<4 x i16> %x, i8* nocapture %p) {
%0 = trunc <4 x i16> %x to <4 x i8>
%1 = bitcast i8* %p to <4 x i8>*
store <4 x i8> %0, <4 x i8>* %1, align 4, !tbaa !2
ret void
}
Can be optimized from:
umov w8, v0.h[3]
umov w9, v0.h[2]
umov w10, v0.h[1]
umov w11, v0.h[0]
strb w8, [x0, #3]
strb w9, [x0, #2]
strb w10, [x0, #1]
strb w11, [x0]
ret
To:
xtn v0.8b, v0.8h
str s0, [x0]
ret
The patch also adjust the memory cost for autovectorization, so the C
code:
void foo (const int *src, int width, unsigned char *dst)
{
for (int i = 0; i < width; i++)
*dst++ = *src++;
}
can be vectorized to:
.LBB0_4: // %vector.body
// =>This Inner Loop Header: Depth=1
ldr q0, [x0], #16
subs x12, x12, #4 // =4
xtn v0.4h, v0.4s
xtn v0.8b, v0.8h
st1 { v0.s }[0], [x2], #4
b.ne .LBB0_4
Instead of byte operations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335735 91177308-0d34-0410-b5e6-96231b3b80d8
This prevents InstCombine from creating mis-sized dbg.values when
replacing a sequence of casts with a simpler cast. For example, in:
(fptrunc (floor (fpext X))) -> (floorf X)
We no longer emit dbg.value(X) (with a 32-bit float operand) to describe
(fpext X) (which is a 64-bit float).
This was diagnosed by the debugify check added in r335682.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335696 91177308-0d34-0410-b5e6-96231b3b80d8
It's not possible to get the fragment size of some dbg.values. Teach the
mis-sized dbg.value diagnostic to detect this scenario and bail out.
Tested with:
$ find test/Transforms -print -exec opt -debugify-each -instcombine {} \;
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335695 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When recording uses we need to rewrite after cloning a loop we need to
check if the use is not dominated by the original def. The initial
assumption was that the cloned basic block will introduce a new path and
thus the original def will only dominate the use if they are in the same
BB, but as the reproducer from PR37745 shows it's not always the case.
This fixes PR37745.
Reviewers: haicheng, Ka-Ka
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D48111
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335675 91177308-0d34-0410-b5e6-96231b3b80d8
Not sure why this logic seems to be repeated in 2 different places,
one called by the other.
On AMDGPU addrspace(3) globals start allocating at 0, so these
checks will be incorrect (not that real code actually tries
to compare these addresses)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335649 91177308-0d34-0410-b5e6-96231b3b80d8
I'm not sure why the code here is skipping calls since
TTI does try to do something for general calls, but it
at least should allow intrinsics.
Skip intrinsics that should not be omitted as calls, which
is by far the most common case on AMDGPU.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335645 91177308-0d34-0410-b5e6-96231b3b80d8
Since D46637 we are better at handling uniform/non-uniform constant Pow2 detection; this patch tweaks the SLP argument handling to support them.
As SLP works with arrays of values I don't think we can easily use the pattern match helpers here.
Differential Revision: https://reviews.llvm.org/D48214
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335621 91177308-0d34-0410-b5e6-96231b3b80d8
Note: I didn't add a hasOneUse() check because the existing,
related fold doesn't have that check. I suspect that the
improved analysis and codegen make these some of the rare
canonicalization cases where we allow an increase in
instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335597 91177308-0d34-0410-b5e6-96231b3b80d8
changeToUnreachable may remove PHI nodes from executable blocks we found values
for and we would fail to replace them. By changing dead blocks to unreachable after
we replaced constants in all executable blocks, we ensure such PHI nodes are replaced
by their known value before.
Fixes PR37780.
Reviewers: efriedma, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D48421
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335588 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is a follow-up to r334830 and r335031.
In the valueCoversEntireFragment check we now also handle
the situation when there is a variable length array (VLA)
involved, and the length of the array has been reduced to
a constant.
The ConvertDebugDeclareToDebugValue functions that are related
to PHI nodes and load instructions now avoid inserting dbg.value
intrinsics when the value does not, for certain, cover the
variable/fragment that should be described.
In r334830 we assumed that the value always covered the entire
var/fragment and we had assertions in the code to show that
assumption. However, those asserts failed when compiling code
with VLAs, so we removed the asserts in r335031. Now when we
know that the valueCoversEntireFragment check can fail also for
PHI/Load instructions we avoid to insert the faulty dbg.value
intrinsic in such situations. Compared to the Store instruction
scenario we simply drop the dbg.value here (as the variable does
not change its value due to PHI/Load, so an earlier dbg.value
describing the variable should still be valid).
Reviewers: aprantl, vsk, efriedma
Reviewed By: aprantl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D48547
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335580 91177308-0d34-0410-b5e6-96231b3b80d8
