As part of making ScalarEvolution's handling of pointers consistent, we
want to forbid multiplying a pointer by -1 (or any other value). This
means we can't blindly subtract pointers.
There are a few ways we could deal with this:
1. We could completely forbid subtracting pointers in getMinusSCEV()
2. We could forbid subracting pointers with different pointer bases
(this patch).
3. We could try to ptrtoint pointer operands.
The option in this patch is more friendly to non-integral pointers: code
that works with normal pointers will also work with non-integral
pointers. And it seems like there are very few places that actually
benefit from the third option.
As a minimal patch, the ScalarEvolution implementation of getMinusSCEV
still ends up subtracting pointers if they have the same base. This
should eliminate the shared pointer base, but eventually we'll need to
rewrite it to avoid negating the pointer base. I plan to do this as a
separate step to allow measuring the compile-time impact.
This doesn't cause obvious functional changes in most cases; the one
case that is significantly affected is ICmpZero handling in LSR (which
is the source of almost all the test changes). The resulting changes
seem okay to me, but suggestions welcome. As an alternative, I tried
explicitly ptrtoint'ing the operands, but the result doesn't seem
obviously better.
I deleted the test lsr-undef-in-binop.ll becuase I couldn't figure out
how to repair it to test what it was actually trying to test.
Recommitting with fix to MemoryDepChecker::isDependent.
Differential Revision: https://reviews.llvm.org/D104806
If any operand of a math op is poison, that takes
precedence over general undef/NaN.
This should not be visible with binary ops because
it requires 2 constant operands to trigger (and if
both operands of a binop are constant, that should
get handled first in ConstantFolding).
As part of making ScalarEvolution's handling of pointers consistent, we
want to forbid multiplying a pointer by -1 (or any other value). This
means we can't blindly subtract pointers.
There are a few ways we could deal with this:
1. We could completely forbid subtracting pointers in getMinusSCEV()
2. We could forbid subracting pointers with different pointer bases
(this patch).
3. We could try to ptrtoint pointer operands.
The option in this patch is more friendly to non-integral pointers: code
that works with normal pointers will also work with non-integral
pointers. And it seems like there are very few places that actually
benefit from the third option.
As a minimal patch, the ScalarEvolution implementation of getMinusSCEV
still ends up subtracting pointers if they have the same base. This
should eliminate the shared pointer base, but eventually we'll need to
rewrite it to avoid negating the pointer base. I plan to do this as a
separate step to allow measuring the compile-time impact.
This doesn't cause obvious functional changes in most cases; the one
case that is significantly affected is ICmpZero handling in LSR (which
is the source of almost all the test changes). The resulting changes
seem okay to me, but suggestions welcome. As an alternative, I tried
explicitly ptrtoint'ing the operands, but the result doesn't seem
obviously better.
I deleted the test lsr-undef-in-binop.ll becuase I couldn't figure out
how to repair it to test what it was actually trying to test.
Differential Revision: https://reviews.llvm.org/D104806
Code assumes that uses of single predecessor phis are not live accross
suspend points. Cleanup any single predecessor phis preceeding the code
making this assumption.
rdar://76020301
Differential Revision: https://reviews.llvm.org/D105488
Compare type IDs and DFS numbering for basic block instead of addresses
to fix non-determinism.
Differential Revision: https://reviews.llvm.org/D105031
The resume partial functions generated for swift suspend points will now
use a Swift mangling suffix.
Await resume partial functions will use the suffix 'TQ'[0-9]+'_' (e.g "...TQ0_")
and suspend resume partial functions will use the suffix 'TY'[0-9]+'_'
(e.g "...TY1_").
Reviewed By: nate_chandler
Differential Revision: https://reviews.llvm.org/D104144
This reverts commit 706bbfb35bd31051e46ac77aab3e9b2dbc3abe78.
The committed version moves the definition of VPReductionPHIRecipe out
of an ifdef only intended for ::print helpers. This should resolve the
build failures that caused the revert
Provide a generic fallback that extends sub-i32 scalars before using the existing sitofp instructions.
These numbers can be tweaked for specific sse levels, but we should get the default handling in place first.
We get the extension for free for non-vector loads.
This patch adds a TTI function, isElementTypeLegalForScalableVector, to query
whether it is possible to vectorize a given element type. This is called by
isLegalToVectorizeInstTypesForScalable to reject scalable vectorization if
any of the instruction types in the loop are unsupported, e.g:
int foo(__int128_t* ptr, int N)
#pragma clang loop vectorize_width(4, scalable)
for (int i=0; i<N; ++i)
ptr[i] = ptr[i] + 42;
This example currently crashes if we attempt to vectorize since i128 is not a
supported type for scalable vectorization.
Reviewed By: sdesmalen, david-arm
Differential Revision: https://reviews.llvm.org/D102253
This reverts commit 3fed6d443f802c43aade1b5b1b09f5e2f8b3edb1,
bbcbf21ae60c928e07dde6a1c468763b3209d1e6 and
6c3451cd76cbd0cd973d9c2b08b168dcd0bce3c2.
The changes causing build failures with certain configurations, e.g.
https://lab.llvm.org/buildbot/#/builders/67/builds/3365/steps/6/logs/stdio
lib/libLLVMVectorize.a(LoopVectorize.cpp.o): In function `llvm::VPRecipeBuilder::tryToCreateWidenRecipe(llvm::Instruction*, llvm::ArrayRef<llvm::VPValue*>, llvm::VFRange&, std::unique_ptr<llvm::VPlan, std::default_delete<llvm::VPlan> >&) [clone .localalias.8]':
LoopVectorize.cpp:(.text._ZN4llvm15VPRecipeBuilder22tryToCreateWidenRecipeEPNS_11InstructionENS_8ArrayRefIPNS_7VPValueEEERNS_7VFRangeERSt10unique_ptrINS_5VPlanESt14default_deleteISA_EE+0x63b): undefined reference to `vtable for llvm::VPReductionPHIRecipe'
collect2: error: ld returned 1 exit status
This patch is a first step towards splitting up VPWidenPHIRecipe into
separate recipes for the 3 distinct cases they model:
1. reduction phis,
2. first-order recurrence phis,
3. pointer induction phis.
This allows untangling the code generation and allows us to reduce the
reliance on LoopVectorizationCostModel during VPlan code generation.
Discussed/suggested in D100102, D100113, D104197.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D104989
that release the retained object
This patch fixes what looks like a longstanding bug in ARC optimizer
where it reverses the order of objc_retain calls and objc_release calls
that retain and release the same object.
The code in ARC optimizer that is responsible for code motion takes the
following steps:
1. Traverse the CFG bottom-up and determine how far up objc_release
calls can be moved. Determine the insertion points for the
objc_release calls, but don't actually move them.
2. Traverse the CFG top-down and determine how far down objc_retain
calls can be moved. Determine the insertion points for the
objc_retain calls, but don't actually move them.
3. Try to move the objc_retain and objc_release calls if they can't be
removed.
The problem is that the insertion points for the objc_retain calls are
determined in step 2 without taking into consideration the insertion
points for objc_release calls determined in step 1, so the order of an
objc_retain call and an objc_release call can be reversed, which is
incorrect, even though each step is correct in isolation.
To fix this bug, this patch teaches the top-down traversal step to take
into consideration the insertion points for objc_release calls
determined in the bottom-up traversal step. Code motion for an
objc_retain call is disabled if there is a possibility that it can be
moved past an objc_release call that releases the retained object.
rdar://79292791
Differential Revision: https://reviews.llvm.org/D104953
This follows up patches for the unsigned siblings:
0c400e895306
c7b658aeb526
We are translating an offset signed compare to its
unsigned equivalent when one end of the range is
at the limit (zero or unsigned max).
(X + C2) >s C --> X <u (SMAX - C) (if C == C2 - 1)
(X + C2) <s C --> X >u (C ^ SMAX) (if C == C2)
This probably does not show up much in IR derived
from C/C++ source because that would likely have
'nsw', and we have folds for that already.
As with the previous unsigned transforms, the folds
could be generalized to handle non-constant patterns:
https://alive2.llvm.org/ce/z/Y8Xrrm
; sgt
define i1 @src(i8 %a, i8 %c) {
%c2 = add i8 %c, 1
%t = add i8 %a, %c2
%ov = icmp sgt i8 %t, %c
ret i1 %ov
}
define i1 @tgt(i8 %a, i8 %c) {
%c_off = sub i8 127, %c ; SMAX
%ov = icmp ult i8 %a, %c_off
ret i1 %ov
}
https://alive2.llvm.org/ce/z/c8uhnk
; slt
define i1 @src(i8 %a, i8 %c) {
%t = add i8 %a, %c
%ov = icmp slt i8 %t, %c
ret i1 %ov
}
define i1 @tgt(i8 %a, i8 %c) {
%c_offnot = xor i8 %c, 127 ; SMAX
%ov = icmp ugt i8 %a, %c_offnot
ret i1 %ov
}
We already have a fold for variable index with constant vector,
but if we can determine a scalar splat value, then it does not
matter whether that value is constant or not.
We overlooked this fold in D102404 and earlier patches,
but the fixed vector variant is shown in:
https://llvm.org/PR50817
Alive2 agrees on that:
https://alive2.llvm.org/ce/z/HpijPC
The same logic applies to scalable vectors.
Differential Revision: https://reviews.llvm.org/D104867
The function vectorizeChainsInBlock does not support scalable vector,
because function like canReuseExtract and isCommutative in the code
path assert with scalable vectors.
This patch avoids vectorizing blocks that have extract instructions with scalable
vector..
Differential Revision: https://reviews.llvm.org/D104809
Loads of <4 x i8> vectors were modeled as extremely expensive. And while we
don't have a load instruction that supports this, it isn't that expensive to
create a vector of i8 elements. The codegen for this was fixed/optimised in
D105110. This now tweaks the cost model and enables SLP vectorisation of my
motivating case loadi8.ll.
Differential Revision: https://reviews.llvm.org/D103629
This replaces the current ad-hoc implementation,
by syncing the code from InstCombine's implementation in `InstCombinerImpl::visitUnreachableInst()`,
with one exception that here in SimplifyCFG we are allowed to remove EH instructions.
Effectively, this now allows SimplifyCFG to remove calls (iff they won't throw and will return),
arithmetic/logic operations, etc.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D105374
This tries to bail out if the PHI is in a `catchswitch` BB in
InstCombine. A PHI cannot be combined into a non-PHI instruction if it
is in a `catchswitch` BB, because `catchswitch` BB cannot have any
non-PHI instruction other than `catchswitch` itself.
The given test case started crashing after D98058.
Reviewed By: lebedev.ri, rnk
Differential Revision: https://reviews.llvm.org/D105309
Somewhat related to D105338.
While it is up for discussion whether or not volatile store traps,
so far there has been no complaints that volatile load/cmpxchg/atomicrmw also may trap.
And even if simplifycfg currently concervatively believes that to be the case,
instcombine does not: https://godbolt.org/z/5vhv4K5b8
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D105343
Update v4i64 -> v4f32/v4f64 uitofp costs based on the worst case costs from the script in D103695.
Fixes a few regressions before we start adding AVX costs for legalized types.
The compiler should not ignore UndefValue when gathering the scalars,
otherwise the resulting code may be less defined than the original one.
Also, grouped scalars to insert them at first to reduce the analysis in
further passes.
Differential Revision: https://reviews.llvm.org/D105275
If the store address does not dominate the matrix multiply, try to hoist
address computation instructions without side-effects and/or memory
reads before the multiply, to allow fusion.
Reviewed By: thegameg
Differential Revision: https://reviews.llvm.org/D105193
This is the cause of the miscompile in:
https://llvm.org/PR50944
The problem has likely existed for some time, but it was made visible with:
5af8bacc94024 ( D104661 )
handleOtherCmpSelSimplifications() assumed it can convert select of
constants to bool logic ops, but that does not work with poison.
We had a very similar construct in InstCombine, so the fix here
mimics the fix there.
The bug is in instsimplify, but I'm not sure how to reproduce it outside of
instcombine. The reason this is visible in instcombine is because we have a
hack (FIXME) to bypass simplification of a select when it has an icmp user:
955f125899/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp (L2632)
So we get to an unusual case where we are trying to simplify an instruction
that has an operand that would have already simplified if we had processed
it in normal order.
Differential Revision: https://reviews.llvm.org/D105298
This follows up to D104665 (which added umulo handling alongside the existing uaddo case), and generalizes for the remaining overflow intrinsics.
I went to add analogous handling to LVI, and discovered that LVI already had a more general implementation. Instead, we can port was LVI does to instcombine. (For context, LVI uses makeExactNoWrapRegion to constrain the value 'x' in blocks reached after a branch on the condition `op.with.overflow(x, C).overflow`.)
Differential Revision: https://reviews.llvm.org/D104932
Building on rG2a1ef8784ad9a, adjust the SSE cost tables to use the legalized types based on the worst case costs from the script in D103695.
To account for different numbers of src/dst legalized type registers we must scale the cost by maximum of the src/dst, not just use src
Now we lack a benchmark to measure the performance change for each
commit.
Since coro elide is the main optimization in coroutine module, I wonder
it may be an estimation to count the number of elided coroutine in
private code bases.
e.g., for a certain commit, if we found that the number of elided goes
down, we could find it before the commit check-in.
Reviewed By: lxfind
Differential Revision: https://reviews.llvm.org/D105095
This is one sibling of the fold added with c7b658aeb526 .
(X + C2) <u C --> X >s ~C2 (if C == C2 + SMIN)
I'm still not sure how to describe it best, but we're
translating 2 constants from an unsigned range comparison
to signed because that eliminates the offset (add) op.
This could be extended to handle the more general (non-constant)
pattern too:
https://alive2.llvm.org/ce/z/K-fMBf
define i1 @src(i8 %a, i8 %c2) {
%t = add i8 %a, %c2
%c = add i8 %c2, 128 ; SMIN
%ov = icmp ult i8 %t, %c
ret i1 %ov
}
define i1 @tgt(i8 %a, i8 %c2) {
%not_c2 = xor i8 %c2, -1
%ov = icmp sgt i8 %a, %not_c2
ret i1 %ov
}
Relevant discussion can be found at: https://lists.llvm.org/pipermail/llvm-dev/2021-January/148197.html
In the existing design, An SCC that contains a coroutine will go through the folloing passes:
Inliner -> CoroSplitPass (fake) -> FunctionSimplificationPipeline -> Inliner -> CoroSplitPass (real) -> FunctionSimplificationPipeline
The first CoroSplitPass doesn't do anything other than putting the SCC back to the queue so that the entire pipeline can repeat.
As you can see, we run Inliner twice on the SCC consecutively without doing any real split, which is unnecessary and likely unintended.
What we really wanted is this:
Inliner -> FunctionSimplificationPipeline -> CoroSplitPass -> FunctionSimplificationPipeline
(note that we don't really need to run Inliner again on the ramp function after split).
Hence the way we do it here is to move CoroSplitPass to the end of the CGSCC pipeline, make it once for real, insert the newly generated SCCs (the clones) back to the pipeline so that they can be optimized, and also add a function simplification pipeline after CoroSplit to optimize the post-split ramp function.
This approach also conforms to how the new pass manager works instead of relying on an adhoc post split cleanup, making it ready for full switch to new pass manager eventually.
By looking at some of the changes to the tests, we can already observe that this changes allows for more optimizations applied to coroutines.
Reviewed By: aeubanks, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D95807
