Summary:
1000 iteratons is still kinda a lot.
Would it make sense to iteratively lower it, until it becomes `2`,
with some delay inbetween in order to let users actually potentially encounter it?
Reviewers: spatel, nikic, kuhar
Reviewed By: nikic
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83160
This is the first and most basic ICV Tracking implementation. For this
first version, we only support deduplication within the same BB.
Reviewers: jdoerfert, JonChesterfield, hamax97, jhuber6, uenoku,
baziotis
Differential Revision: https://reviews.llvm.org/D81788
Assume bundle can have more than one entry with the same name,
but at least AlignmentFromAssumptionsPass::extractAlignmentInfo() uses
getOperandBundle("align"), which internally assumes that it isn't the
case, and happily crashes otherwise.
Minimal reduced reproducer: run `opt -alignment-from-assumptions` on
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
%0 = type { i64, %1*, i8*, i64, %2, i32, %3*, i8* }
%1 = type opaque
%2 = type { i8, i8, i16 }
%3 = type { i32, i32, i32, i32 }
; Function Attrs: nounwind
define i32 @f(%0* noalias nocapture readonly %arg, %0* noalias %arg1) local_unnamed_addr #0 {
bb:
call void @llvm.assume(i1 true) [ "align"(%0* %arg, i64 8), "align"(%0* %arg1, i64 8) ]
ret i32 0
}
; Function Attrs: nounwind willreturn
declare void @llvm.assume(i1) #1
attributes #0 = { nounwind "reciprocal-estimates"="none" }
attributes #1 = { nounwind willreturn }
This is what we'd have with -mllvm -enable-knowledge-retention
This reverts commit c95ffadb24.
clang w/ old-pm currently would simply crash
when -mllvm -enable-knowledge-retention=true is specified.
Clearly, these two passes had no Old-PM test coverage,
which would have shown the problem - not requiring AssumptionCacheTracker,
but then trying to always get it.
Also, why try to get domtree only if it's cached,
but at the same time marking it as required?
As noted in PR46561:
https://bugs.llvm.org/show_bug.cgi?id=46561
...it takes something beyond a minimal IR example to trigger
this bug because it relies on matching non-canonical IR.
There are no tests that show the need for matching this
pattern, so I'm just deleting it to fix the miscompile.
Summary:
The actual transform i was going after was:
https://rise4fun.com/Alive/Tp9H
```
Name: zz
Pre: isPowerOf2(C0) && isPowerOf2(C1) && C1 == C0
%t0 = and i8 %x, C0
%r = icmp eq i8 %t0, C1
=>
%t = icmp eq i8 %t0, 0
%r = xor i1 %t, -1
Name: zz
Pre: isPowerOf2(C0)
%t0 = and i8 %x, C0
%r = icmp ne i8 %t0, 0
=>
%t = icmp eq i8 %t0, 0
%r = xor i1 %t, -1
```
but as it can be seen from the current tests, we already canonicalize most of it,
and we are only missing handling multi-use non-canonical icmp predicates.
If we have both `!=0` and `==0`, even though we can CSE them,
we end up being stuck with them. We should canonicalize to the `==0`.
I believe this is one of the cleanup steps i'll need after `-scalarizer`
if i end up proceeding with my WIP alloca promotion helper pass.
Reviewers: spatel, jdoerfert, nikic
Reviewed By: nikic
Subscribers: zzheng, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83139
The use of 'tmp' can trigger warnings from the update_test_checks.py
script. That's evidence of a flaw in the script's logic, but we
can always do better than naming variables 'tmp' in LLVM too.
The phi test file should be updated with auto-generated regex CHECK
lines, so it isn't affected by cosmetic diffs, but I don't have
time to do that right now.
This emits a remark when LoopDeletion deletes a dead loop, using the
source location of the loop's header. There are currently two reasons
for removing the loop: invariant loop or loop that never executes.
Differential Revision: https://reviews.llvm.org/D83113
Narrowing an input expression of a truncate to a type larger than the
result of the truncate won't allow removing the truncate, but it may
enable further optimizations, e.g. allowing for larger vectorization
factors.
For now this is intentionally limited to integer types only, to avoid
producing new vector ops that might not be suitable for the target.
If we know that the only user is a trunc, we can also be allow more
cases, e.g. also shortening expressions with some additional shifts.
I would appreciate feedback on the best place to do such a narrowing.
This fixes PR43580.
Reviewers: spatel, RKSimon, lebedev.ri, xbolva00
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D82973
The base case only works because we are relying on a
poison-unsafe select transform; if that is fixed, we
would regress on patterns like this.
The extra use tests show that the select transform can't
be applied consistently. So it may be a regression to have
an extra instruction on 1 test, but that result was not
created safely and does not happen reliably.
The entries in VectorizableTree are not necessarily ordered by their
position in basic blocks. Collect them and order them by dominance so
later instructions are guaranteed to be visited first. For instructions
in different basic blocks, we only scan to the beginning of the block,
so their order does not matter, as long as all instructions in a basic
block are grouped together. Using dominance ensures a deterministic order.
The modified test case contains an example where we compute a wrong
spill cost (2) without this patch, even though there is no call between
any instruction in the bundle.
This seems to have limited practical impact, .e.g on X86 with a recent
Intel Xeon CPU with -O3 -march=native -flto on MultiSource,SPEC2000,SPEC2006
there are no binary changes.
Reviewers: craig.topper, RKSimon, xbolva00, ABataev, spatel
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D82444
Currently canEvaluateTruncated can only attempt to truncate shifts if they are scalar/uniform constant amounts that are in range.
This patch replaces the constant extraction code with KnownBits handling, using the KnownBits::getMaxValue to check that the amounts are inrange.
This enables support for nonuniform constant cases, and also variable shift amounts that have been masked somehow. Annoyingly, this still won't work for vectors with (demanded) undefs as KnownBits returns nothing in those cases, but its a definite improvement on what we currently have.
Differential Revision: https://reviews.llvm.org/D83127
As noted on PR46531, we were only performing this transform on uniform vectors as we were using the m_APInt pattern matcher to extract the shift amount.
Differential Revision: https://reviews.llvm.org/D83035
LowerConstantIntrinsics fails to preserve the analysis result of
GlobalsAA. Not preserving the analysis might affect benchmark
performance. This change fixes this issue.
Patch by Ryan Santhiraraja <rsanthir@quicinc.com>
Reviewers: fpetrogalli, joerg, fhahn
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D82342
This patch enables the LoopVectorizer to build a phi of pointer
type and provide the vector loads and stores with vector type
getelementptrs built from the pointer induction variable, which
produces much less instructions than the previous approach of
creating scalar getelementpointers and glue them together to a
vector.
Differential Revision: https://reviews.llvm.org/D81267
Summary:
This patch changes call graph analysis to recognize callback call sites
and add an artificial 'reference' call record from the broker function
caller to the callback function in the call graph. A presence of such
reference enforces bottom-up traversal order for callback functions in
CG SCC pass manager because callback function logically becomes a callee
of the broker function caller.
Reviewers: jdoerfert, hfinkel, sstefan1, baziotis
Reviewed By: jdoerfert
Subscribers: hiraditya, kuter, sstefan1, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82572
If the addend of the fma is zero, common sense would suggest that we can
convert fma x, y, 0.0 to fmul x, y. This comes up with some user code
that was expecting the first fma in an unrolled loop to simplify to a
fmul.
Floating point often does not follow naive common sense though. Alive
suggests that this should be guarded by nsz (as fadd -0.0, 0.0 = 0.0).
fma x, y, -0.0 is always valid.
Differential Revision: https://reviews.llvm.org/D82778
Sometimes SimplifyCFG may decide to perform jump threading. In order
to do it, it follows the following algorithm:
1. Checks if the block is small enough for threading;
2. If yes, inserts a PR Phi relying that the next iteration will remove it
by performing jump threading;
3. The next iteration checks the block again and performs the threading.
This logic has a corner case: inserting the PR Phi increases block's size
by 1. If the block size at first check was max possible, one more Phi will
exceed this size, and we will neither perform threading nor remove the
created Phi node. As result, we will end up with worse IR than before.
This patch fixes this situation by excluding Phis from block size computation.
Excluding Phis from size computation for threading also makes sense by
itself because in case of threadign all those Phis will be removed.
Differential Revision: https://reviews.llvm.org/D81835
Reviewed By: asbirlea, nikic
It's possible for the first loop trip(s) to set the `Changed` Status, and to a
later one to early exit, in which case `Changed` must be return.
Differential Revision: https://reviews.llvm.org/D82753
binop i1 (cmp Pred (ext X, Index0), C0), (cmp Pred (ext X, Index1), C1)
-->
vcmp = cmp Pred X, VecC
ext (binop vNi1 vcmp, (shuffle vcmp, Index1)), Index0
This is a larger pattern than the existing extractelement folds because we can't
reasonably vectorize the sub-patterns with constants based on cost model calcs
(it doesn't usually make sense to replace a single extracted scalar op with
constant operand with a vector op).
I salvaged as much of the existing logic as I could, but there might be better
ways to share and reduce code.
The motivating case from PR43745:
https://bugs.llvm.org/show_bug.cgi?id=43745
...is the special case of a 2-way reduction. We tried to get SLP to handle that
particular pattern in D59710, but that caused crashing and regressions.
This patch is more general, but hopefully safer.
The v2f64 test with SSE2 surprised me - the cost model accounting looks like this:
OldCost = 0 (free extract of f64 at index 0) + 1 (extract of f64 at index 1) + 2 (scalar fcmps) + 1 (and of bools) = 4
NewCost = 2 (vector fcmp) + 1 (shuffle) + 1 (vector 'and') + 1 (extract of bool) = 5
Differential Revision: https://reviews.llvm.org/D82474
Summary:
If we ever assign co_await to a temporary variable, such as foo(co_await expr),
we generate AST that looks like this: MaterializedTemporaryExpr(CoawaitExpr(...)).
MaterializedTemporaryExpr would emit an intrinsics that marks the lifetime start of the
temporary storage. However such temporary storage will not be used until co_await is ready
to write the result. Marking the lifetime start way too early causes extra storage to be
put in the coroutine frame instead of the stack.
As you can see from https://godbolt.org/z/zVx_eB, the frame generated for get_big_object2 is 12K, which contains a big_object object unnecessarily.
After this patch, the frame size for get_big_object2 is now only 8K. There are still room for improvements, in particular, GCC has a 4K frame for this function. But that's a separate problem and not addressed in this patch.
The basic idea of this patch is during CoroSplit, look for every local variable in the coroutine created through AllocaInst, identify all the lifetime start/end markers and the use of the variables, and sink the lifetime.start maker to the places as close to the first-ever use as possible.
Reviewers: lewissbaker, modocache, junparser
Reviewed By: junparser
Subscribers: hiraditya, llvm-commits, rsmith, ChuanqiXu, cfe-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D82314
These need special handling over the simple vector intrinsics as they
behave more like a shuffle operation: taking the top half of the vector
from one input, and the bottom half separately. Previously, these were
being handled as though all bits of all operands were combined.
Differential Revision: https://reviews.llvm.org/D82398
Summary:
The advice in HowToUpdateDebugInfo.rst is to "... preserve the debug
location of an instruction if the instruction either remains in its
basic block, or if its basic block is folded into a predecessor that
branches unconditionally".
TryToSinkInstruction doesn't seem to satisfy the criteria as it's
sinking an instruction to some successor block. Preserving the debug loc
can make single-stepping appear to go backwards, or make a breakpoint
hit on that location happen "too late" (since single-stepping from that
breakpoint can cause the function to return unexpectedly).
So, drop the debug location.
This was reverted in ee3620643d because it removed source locations
from inlinable calls, breaking a verifier rule. I've added an exception
for calls because the alternative (setting a line 0 location) is not
better. I tested the updated patch by completing a stage2 RelWithDebInfo
build.
Reviewers: aprantl, davide
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82487
In https://reviews.llvm.org/D81198, we outlined a number of scenarios
where dropping debug locations is appropriate. Stop issuing an error
when this happens.
Summary:
The advice in HowToUpdateDebugInfo.rst is to "... preserve the debug
location of an instruction if the instruction either remains in its
basic block, or if its basic block is folded into a predecessor that
branches unconditionally".
TryToSinkInstruction doesn't seem to satisfy the criteria as it's
sinking an instruction to some successor block. Preserving the debug loc
can make single-stepping appear to go backwards, or make a breakpoint
hit on that location happen "too late" (since single-stepping from that
breakpoint can cause the function to return unexpectedly).
So, drop the debug location.
Reviewers: aprantl, davide
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82487
This patch adds VPValue version of the GEP's operands to
VPWidenGEPRecipe and uses them during code-generation.
Reviewers: Ayal, gilr, rengolin
Reviewed By: gilr
Differential Revision: https://reviews.llvm.org/D80220
Add an option to always instrument function entry BB (default off)
Add an option to do atomically updates on the first counter in each
instrumented function.
Differential Revision: https://reviews.llvm.org/D82123
Roman Lebedev