Currently if an OpenMP program uses `linear` clause, and is compiled with
optimization, `llvm.lifetime.end` for variables listed in `linear` clause are
emitted too early such that there could still be uses after that. Let's take the
following code as example:
```
// loop.c
int j;
int *u;
void loop(int n) {
int i;
for (i = 0; i < n; ++i) {
++j;
u = &j;
}
}
```
We compile using the command:
```
clang -cc1 -fopenmp-simd -O3 -x c -triple x86_64-apple-darwin10 -emit-llvm loop.c -o loop.ll
```
The following IR (simplified) will be generated:
```
@j = local_unnamed_addr global i32 0, align 4
@u = local_unnamed_addr global ptr null, align 8
define void @loop(i32 noundef %n) local_unnamed_addr {
entry:
%j = alloca i32, align 4
%cmp = icmp sgt i32 %n, 0
br i1 %cmp, label %simd.if.then, label %simd.if.end
simd.if.then: ; preds = %entry
call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %j)
store ptr %j, ptr @u, align 8
call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %j)
%0 = load i32, ptr %j, align 4
store i32 %0, ptr @j, align 4
br label %simd.if.end
simd.if.end: ; preds = %simd.if.then, %entry
ret void
}
```
The most important part is:
```
call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %j)
%0 = load i32, ptr %j, align 4
store i32 %0, ptr @j, align 4
```
`%j` is still loaded after `@llvm.lifetime.end.p0(i64 4, ptr nonnull %j)`. This
could cause the backend incorrectly optimizes the code and further generates
incorrect code. The root cause is, when we emit a construct that could have
`linear` clause, it usually has the following pattern:
```
EmitOMPLinearClauseInit(S)
{
OMPPrivateScope LoopScope(*this);
...
EmitOMPLinearClause(S, LoopScope);
...
(void)LoopScope.Privatize();
...
}
EmitOMPLinearClauseFinal(S, [](CodeGenFunction &) { return nullptr; });
```
Variables that need to be privatized are added into `LoopScope`, which also
serves as a RAII object. When `LoopScope` is destructed and if optimization is
enabled, a `@llvm.lifetime.end` is also emitted for each privatized variable.
However, the writing back to original variables in `linear` clause happens after
the scope in `EmitOMPLinearClauseFinal`, causing the issue we see above.
A quick "fix" seems to be, moving `EmitOMPLinearClauseFinal` inside the scope.
However, it doesn't work. That's because the local variable map has been updated
by `LoopScope` such that a variable declaration is mapped to the privatized
variable, instead of the actual one. In that way, the following code will be
generated:
```
%0 = load i32, ptr %j, align 4
store i32 %0, ptr %j, align 4
call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %j)
```
Well, now the life time is correct, but apparently the writing back is broken.
In this patch, a new function `OMPPrivateScope::restoreMap` is added and called
before calling `EmitOMPLinearClauseFinal`. This can make sure that
`EmitOMPLinearClauseFinal` can find the orignal varaibls to write back.
Fixes#56913.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D131272
The order has to be a constant and should be enforced by the builtin
definition. The fallthrough behavior would have been broken anyway.
There's still an existing issue/assert if you try to use garbage for the
ordering. The IRGen should be broken, but we also hit another assert
before that.
Fixes issue 56832
As discussed in [0], this diff adds the `skipprofile` attribute to
prevent the function from being profiled while allowing profiled
functions to be inlined into it. The `noprofile` attribute remains
unchanged.
The `noprofile` attribute is used for functions where it is
dangerous to add instrumentation to while the `skipprofile` attribute is
used to reduce code size or performance overhead.
[0] https://discourse.llvm.org/t/why-does-the-noprofile-attribute-restrict-inlining/64108
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D130807
This completes the implementation of P1091R3 and P1381R1.
This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.
In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.
We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.
In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.
Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.
at the request of @shafik, i can confirm the correct behavior of lldb wit this change.
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D122768
This completes the implementation of P1091R3 and P1381R1.
This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.
In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.
We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.
In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.
Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.
at the request of @shafik, i can confirm the correct behavior of lldb wit this change.
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D122768
Information in the function `Prologue Data` is intentionally opaque.
When a function with `Prologue Data` is duplicated. The self (global
value) references inside `Prologue Data` is still pointing to the
original function. This may cause errors like `fatal error: error in backend: Cannot represent a difference across sections`.
This patch detaches the information from function `Prologue Data`
and attaches it to a function metadata node.
This and D116130 fix https://github.com/llvm/llvm-project/issues/49689.
Reviewed By: pcc
Differential Revision: https://reviews.llvm.org/D115844
Implementing target in_reduction by wrapping target task with host task with in_reduction and if clause. This is in compliance with OpenMP 5.0 section: 2.19.5.6.
So, this
```
for (int i=0; i<N; i++) {
res = res+i
}
```
will become
```
#pragma omp task in_reduction(+:res) if(0)
#pragma omp target map(res)
for (int i=0; i<N; i++) {
res = res+i
}
```
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D125669
Add option -fhip-kernel-arg-name to emit kernel argument
name metadata, which is needed for certain HIP applications.
Reviewed by: Artem Belevich, Fangrui Song, Brian Sumner
Differential Revision: https://reviews.llvm.org/D128022
Fix __has_builtin to return 1 only if the requested target features
of a builtin are enabled by refactoring the code for checking
required target features of a builtin and use it in evaluation
of __has_builtin.
Reviewed by: Artem Belevich
Differential Revision: https://reviews.llvm.org/D125829
The callback is expected to create a branch to the ContinuationBB (sometimes called FiniBB in some lambdas) argument when finishing. This creates problems:
1. The InsertPoint used for CodeGenIP does not need to be the end of a block. If it is not, a naive callback will insert a branch instruction into the middle of the block.
2. The BasicBlock the CodeGenIP is pointing to may or may not have a terminator. There is an conflict where to branch to if the block already has a terminator.
3. Some API functions work only with block having a terminator. Some workarounds have been used to insert a temporary terminator that is removed again.
4. Some callbacks are sensitive to whether the BasicBlock has a terminator or not. This creates a callback ordering problem where different callback may have different behaviour depending on whether a previous callback created a terminator or not. The problem also exists for FinalizeCallbackTy where some callbacks do create branch to another "continue" block, but unlike BodyGenCallbackTy does not receive the target as argument. This is not addressed in this patch.
With this patch, the callback receives an CodeGenIP into a BasicBlock where to insert instructions. If it has to insert control flow, it can split the block at that position as needed but otherwise no separate ContinuationBB is needed. In particular, a callback can be empty without breaking the emitted IR. If the caller needs the control flow to branch to a specific target, it can insert the branch instruction itself and pass an InsertPoint before the terminator to the callback.
Certain frontends such as Clang may expect the current IRBuilder position to be at the end of a basic block. In this case its callbacks must split the block at CodeGenIP before setting the IRBuilder position such that the instructions after CodeGenIP are moved to another basic block and before returning create a new branch instruction to the split block.
Some utility functions such as `splitBB` are supporting correct splitting of BasicBlocks, independent of whether they have a terminator or not, returning/setting the InsertPoint of an IRBuilder to the end of split predecessor block, and optionally omitting creating a branch to the split successor block to be added later.
Reviewed By: kiranchandramohan
Differential Revision: https://reviews.llvm.org/D118409
Currently we emit an error in just about every case of conditionals
with a 'non simple' branch if treated as an LValue. This patch adds
support for the special case where this is an 'ignored' lvalue, which
permits the side effects from happening.
It also splits up the emit for conditional LValue in a way that should
be usable to handle simple assignment expressions in similar situations.
Differential Revision: https://reviews.llvm.org/D123680
This requires some adjustment in caller code, because there was
a confusion regarding the meaning of the PtrTy argument: This
argument is the type of the pointer being loaded, not the addresses
being loaded from.
Reapply after fixing the specified pointer type for one call in
47eb4f7dcd, where the used type is
important for determining alignment.
This requires some adjustment in caller code, because there was
a confusion regarding the meaning of the PtrTy argument: This
argument is the type of the pointer being loaded, not the addresses
being loaded from.
This is the `ext_vector_type` alternative to D81083.
This patch extends Clang to allow 'bool' as a valid vector element type
(attribute ext_vector_type) in C/C++.
This is intended as the canonical type for SIMD masks and facilitates
clean vector intrinsic declarations. Vectors of i1 are supported on IR
level and below down to many SIMD ISAs, such as AVX512, ARM SVE (fixed
vector length) and the VE target (NEC SX-Aurora TSUBASA).
The RFC on cfe-dev: https://lists.llvm.org/pipermail/cfe-dev/2020-May/065434.html
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D88905
Motivation:
```
int test(int x, int y) {
int r = 0;
[[clang::always_inline]] r += foo(x, y); // force compiler to inline this function here
return r;
}
```
In 2018, @kuhar proposed "Introduce per-callsite inline intrinsics" in https://reviews.llvm.org/D51200 to solve this motivation case (and many others).
This patch solves this problem with call site attribute. "noinline" statement attribute already landed in D119061. Also, some LLVM Inliner fixes landed so call site attribute is stronger than function attribute.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D120717
* Use default ref capture for non-escaping lambdas (this makes
maintenance easier by allowing new uses, removing uses, having
conditional uses (such as in assertions) not require updates to an
explicit capture list)
* Simplify addPrivate API not to take a lambda, since it calls it
unconditionally/immediately anyway - most callers are simply passing
in a named value or short expression anyway and the lambda syntax just
adds noise/overhead
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D121077
Motivation:
```
int foo(int x, int y) { // any compiler will happily inline this function
return x / y;
}
int test(int x, int y) {
int r = 0;
[[clang::noinline]] r += foo(x, y); // for some reason we don't want any inlining here
return r;
}
```
In 2018, @kuhar proposed "Introduce per-callsite inline intrinsics" in https://reviews.llvm.org/D51200 to solve this motivation case (and many others).
This patch solves this problem with call site attribute. The implementation is "smaller" wrt approach which uses new intrinsics and thanks to https://reviews.llvm.org/D79121 (Add nomerge statement attribute to clang), we have got some basic infrastructure to deal with attrs on statements with call expressions.
GCC devs are more inclined to call attribute solution as well, as builtins are problematic for them - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104187. But they have no patch proposal yet so.. We have free hands here.
If this approach makes sense, next future steps would be support for call site attributes for always_inline / flatten.
Reviewed By: aaron.ballman, kuhar
Differential Revision: https://reviews.llvm.org/D119061
This implements the clang side of D116531. The elementtype
attribute is added for all indirect constraints (*) and tests are
updated accordingly.
Differential Revision: https://reviews.llvm.org/D116666
In 32bit mode, attaching TBAA metadata to the store following the call
to inline assembler results in describing the wrong type by making a
fake lvalue(i.e., whatever the inline assembler happens to leave in
EAX:EDX.) Even if inline assembler somehow describes the correct type,
setting TBAA information on return type of call to inline assembler is
likely not correct, since TBAA rules need not apply to inline assembler.
Differential Revision: https://reviews.llvm.org/D115320
Extension of D112504. Lower amdgpu printf to `__llvm_omp_vprintf`
which takes the same const char*, void* arguments as cuda vprintf and also
passes the size of the void* alloca which will be needed by a non-stub
implementation of `__llvm_omp_vprintf` for amdgpu.
This removes the amdgpu link error on any printf in a target region in favour
of silently compiling code that doesn't print anything to stdout.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D112680
at the start of the entry block, which in turn would aid better code transformation/optimization.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D110257
Extension of D112504. Lower amdgpu printf to `__llvm_omp_vprintf`
which takes the same const char*, void* arguments as cuda vprintf and also
passes the size of the void* alloca which will be needed by a non-stub
implementation of `__llvm_omp_vprintf` for amdgpu.
This removes the amdgpu link error on any printf in a target region in favour
of silently compiling code that doesn't print anything to stdout.
The exact set of changes to check-openmp probably needs revision before commit
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D112680
Parallel regions are outlined as functions with capture variables explicitly generated as distinct parameters in the function's argument list. That complicates the fork_call interface in the OpenMP runtime: (1) the fork_call is variadic since there is a variable number of arguments to forward to the outlined function, (2) wrapping/unwrapping arguments happens in the OpenMP runtime, which is sub-optimal, has been a source of ABI bugs, and has a hardcoded limit (16) in the number of arguments, (3) forwarded arguments must cast to pointer types, which complicates debugging. This patch avoids those issues by aggregating captured arguments in a struct to pass to the fork_call.
Reviewed By: jdoerfert, jhuber6
Differential Revision: https://reviews.llvm.org/D102107
This patch supports OpenMP 5.0 metadirective features.
It is implemented keeping the OpenMP 5.1 features like dynamic user condition in mind.
A new function, getBestWhenMatchForContext, is defined in llvm/Frontend/OpenMP/OMPContext.h
Currently this function return the index of the when clause with the highest score from the ones applicable in the Context.
But this function is declared with an array which can be used in OpenMP 5.1 implementation to select all the valid when clauses which can be resolved in runtime. Currently this array is set to null by default and its implementation is left for future.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D91944
This patch supports OpenMP 5.0 metadirective features.
It is implemented keeping the OpenMP 5.1 features like dynamic user condition in mind.
A new function, getBestWhenMatchForContext, is defined in llvm/Frontend/OpenMP/OMPContext.h
Currently this function return the index of the when clause with the highest score from the ones applicable in the Context.
But this function is declared with an array which can be used in OpenMP 5.1 implementation to select all the valid when clauses which can be resolved in runtime. Currently this array is set to null by default and its implementation is left for future.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D91944
This patch supports OpenMP 5.0 metadirective features.
It is implemented keeping the OpenMP 5.1 features like dynamic user condition in mind.
A new function, getBestWhenMatchForContext, is defined in llvm/Frontend/OpenMP/OMPContext.h
Currently this function return the index of the when clause with the highest score from the ones applicable in the Context.
But this function is declared with an array which can be used in OpenMP 5.1 implementation to select all the valid when clauses which can be resolved in runtime. Currently this array is set to null by default and its implementation is left for future.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D91944
