Improved/fixed cost modeling for shuffles by providing masks, improved
cost model for non-identity insertelements.
Differential Revision: https://reviews.llvm.org/D115462
Async context frames are allocated with a maximum alignment. If a type
requests an alignment bigger than that dynamically align the address
in the frame.
Differential Revision: https://reviews.llvm.org/D126715
This patch removes CondBit and Predicate from VPBasicBlock. To do so,
the patch introduces a new branch-on-cond VPInstruction opcode to model
a branch on a condition explicitly.
This addresses a long-standing TODO/FIXME that blocks shouldn't be users
of VPValues. Those extra users can cause issues for VPValue-based
analyses that don't expect blocks. Addressing this fixme should allow us
to re-introduce 266ea446ab.
The generic branch opcode can also be used in follow-up patches.
Depends on D123005.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D126618
If all available vals to basic block are the same - do not build new phi node and
just use this value.
Reviewed By: sameerds
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D126525
This patch proposed to use a new cost model for loop interchange, which
is obtained from loop cache analysis.
Given a loopnest, what loop cache analysis returns is a vector of loops
[loop0, loop1, loop2, ...] where loop0 should be replaced as the outermost
loop, loop1 should be placed one more level inside, and loop2 one more level
inside, etc. What loop cache analysis does is not only more comprehensive than
the current cost model, it is also a "one-shot" query which means that we only
need to query it once during the entire loop interchange pass, which is better
than the current cost model where we query it every time we check whether it is
profitable to interchange two loops. Thus complexity is reduced, especially after
D120386 where we do more interchanges to get the globally optimal loop access pattern.
Updates made to test cases are mostly minor changes and some corrections.
Test coverage for loop interchange is not reduced.
Currently we did not completely remove the legacy cost model, but keep it as
fall-back in case the new cost model did not run successfully. This is because
currently we have some limitations in delinearization, which sometimes makes
loop cache analysis bail out. The longer term goal is to enhance delinearization
and eventually remove the legacy cost model compeletely.
Reviewed By: bmahjour, #loopoptwg
Differential Revision: https://reviews.llvm.org/D124926
Improved/fixed cost modeling for shuffles by providing masks, improved
cost model for non-identity insertelements.
Differential Revision: https://reviews.llvm.org/D115462
This enabled opaque pointers by default in LLVM. The effect of this
is twofold:
* If IR that contains *neither* explicit ptr nor %T* types is passed
to tools, we will now use opaque pointer mode, unless
-opaque-pointers=0 has been explicitly passed.
* Users of LLVM as a library will now default to opaque pointers.
It is possible to opt-out by calling setOpaquePointers(false) on
LLVMContext.
A cmake option to toggle this default will not be provided. Frontends
or other tools that want to (temporarily) keep using typed pointers
should disable opaque pointers via LLVMContext.
Differential Revision: https://reviews.llvm.org/D126689
Improved/fixed cost modeling for shuffles by providing masks, improved
cost model for non-identity insertelements.
Differential Revision: https://reviews.llvm.org/D115462
Extractelement instructions may come from different basic blocks, need
to take it into account when looking for a last instruction in the
bundle to prevent compiler crash.
Differential Revision: https://reviews.llvm.org/D126777
This reverts commit ec4adf1f6c. The commit causes
clang to hang on a certain input:
```
$ cat q.cc
int f(int a, int b) {
int c = ((unsigned char)(a >> 23) & 925);
if (a)
c = (a >> 23 & b) | ((unsigned char)(a >> 23) & 925) | (b >> 23 & 157);
return c;
}
$ time ./clang-15-10515 --target=x86_64--linux-gnu -O1 -c q.cc
^C
real 0m45.072s
user 0m0.025s
sys 0m0.099s
```
This patch updates the VPlan native path to use VPRegionBlocks for all
loops in a loop nest. Up to now, only the outermost loop used a region.
This is a step towards unifying both paths and keep things consistent
between them. It also prepares various code-gen parts for modeling the
pre-header in the inner loop vectorizer (D121624).
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D123005
Now that SimpleLoopUnswitch and other transforms no longer introduce
branch on poison, enable the -branch-on-poison-as-ub option by
default. The practical impact of this is mostly better flag
preservation in SCEV, and some freeze instructions no longer being
necessary.
Differential Revision: https://reviews.llvm.org/D125299
Commit dd5991cc modified the aliasing checks here to allow transforming
a memcpy where the source and destination point into the same object.
However, the change accidentally made the code skip the alias check for
other operations in the loop.
Instead of completely skipping the alias check, just skip the check for
whether the memcpy aliases itself.
Differential Revision: https://reviews.llvm.org/D126486
X <=u (sext i1 Y) --> (X == 0) | Y
https://alive2.llvm.org/ce/z/W_tZzo
This is the conjugate/sibling pattern suggested with D126171
for a sign-extended bool value.
When reassociating GEPs, we can only keep inbounds if both original
GEPs were inbounds, and their offsets have the same sign. For the
sake of simplicity, I only handle the case where both offsets are
non-negative here.
It would probably be fine to just not preserve inbounds at all here,
but as I don't see a compile-time impact for adding the
isKnownNonNegative() calls I went with this more conservative
approach.
Fixes https://github.com/llvm/llvm-project/issues/44206.
Differential Revision: https://reviews.llvm.org/D126687
Even if the total offset is inbounds, we might represent it by first
performing a large negative offset and then a small positive one.
With inbounds semantics as currently specified, each offset must
be inbounds individually, not just the overall offset of the GEP.
Fix this by checking that the sign of all offsets is the same.
Fixes https://github.com/llvm/llvm-project/issues/55722.
(C2 >> X) >> C1 --> (C2 >> C1) >> X
The shift-left form of this transform has existed since:
16f18ed7b5
...but it applies to matching shift right opcodes too:
https://alive2.llvm.org/ce/z/c5eQms
The restriction goes back to:
16f18ed7b5
...but the fold only replaces a shift with a shift, so that's not necessary.
Generalizing to other opcodes is planned as a follow-up.
There are a few places where we use report_fatal_error when the input is broken.
Currently, this function always crashes LLVM with an abort signal, which
then triggers the backtrace printing code.
I think this is excessive, as wrong input shouldn't give a link to
LLVM's github issue URL and tell users to file a bug report.
We shouldn't print a stack trace either.
This patch changes report_fatal_error so it uses exit() rather than
abort() when its argument GenCrashDiag=false.
Reviewed by: nikic, MaskRay, RKSimon
Differential Revision: https://reviews.llvm.org/D126550
If only one of the GEPs is inbounds, then after swapping, there is
no guarantee that one of them will be inbounds as well
(see e.g. https://alive2.llvm.org/ce/z/agaCnp).
This is only a partial fix, because even if both are inbounds, the
result is not necessarily inbounds (if the offsets have different
signs).
As the long explanatory comment attests, performing the modification
in place is pretty tricky. Drop this unnecessary complexity and
always create new instructions.
This should be NFC-ish, but can probably cause difference due to
worklist order.
This option was added in D89854. It prevents GVN from performing
load PRE in a loop, if doing so would require critical edge
splitting on the backedge. From the review:
> I know that GVN Load PRE negatively impacts peeling,
> loop predication, so the passes expecting that latch has
> a conditional branch.
In the PhaseOrdering test in this patch, splitting the backedge
negatively affects vectorization: After critical edge splitting,
the loop gets rotated, effectively peeling off the first loop
iteration. The effect is that the first element is handled
separately, then the bulk of the elements use a vectorized
reduction (but using unaligned, off-by-one memory accesses) and
then a tail of 15 elements is handled separately again.
It's probably worth noting that the loop load PRE from D99926 is
not affected by this change (as it does not need backedge
splitting). This is about normal load PRE that happens to occur
inside a loop.
Differential Revision: https://reviews.llvm.org/D126382
This reverts the revert commit ad95255b92.
The updated version also creates a load when the store may not execute.
In those cases, we still need to introduce a load in a function where
there may not have been one before, so this doesn't completely resolve
issue #51248.
Original message:
When only a store is sunk, there is no need to create a load in the
pre-header, as the result of the load will never get used.
The dead load can can introduce UB, if the function is marked as
writeonly.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D123473
(ashr i32 X, 31) * C --> (X < 0) ? -C : 0
https://alive2.llvm.org/ce/z/G8u9SS
With a constant operand, this is an improvement in IR
and codegen (where it can be converted to a mask op).
Without a constant operand, we would have to negate
the operand, so that is probably better left to the backend.
This is similar but not the same optimization that is requested
in #55618.
If the fma operates on a legal vector type, the indexed variants can be
used, if the second operand is a splat of a valid index.
Reviewed By: dmgreen
Differential Revision: https://reviews.llvm.org/D126234
```
void vector_reverse_i64(int *A, int *B, int n) {
#pragma clang loop vectorize_width(4, scalable)
for (int i = n-1; i >= 0; i--)
A[i] = B[i] + 1;
}
```
When option: scalable-vectorization is on (or set #pragma clang loop vectorize_width(elements, scalable)), Reverse Iterators can't loop vectorization as <vscale x elements x elementType>
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D125866
