Inner bodies of OpenMP worksharing loop-based constructs with dynamic or guided scheduling are allowed to be marked with !llvm.mem.parallel_loop_access metadata for better optimization. Worksharing constructs with static scheduling cannot be marked this way (according to OpenMP standard "A data dependence between the same logical iterations in two such loops is guaranteed").
Constructs with auto and runtime scheduling are also not marked because automatically chosen scheduling may be static also.
Differential Revision: http://reviews.llvm.org/D9518
llvm-svn: 236693
For tasks codegen for private/firstprivate variables are different rather than for other directives.
1. Build an internal structure of privates for each private variable:
struct .kmp_privates_t. {
Ty1 var1;
...
Tyn varn;
};
2. Add a new field to kmp_task_t type with list of privates.
struct kmp_task_t {
void * shareds;
kmp_routine_entry_t routine;
kmp_int32 part_id;
kmp_routine_entry_t destructors;
.kmp_privates_t. privates;
};
3. Create a function with destructors calls for all privates after end of task region.
kmp_int32 .omp_task_destructor.(kmp_int32 gtid, kmp_task_t *tt) {
~Destructor(&tt->privates.var1);
...
~Destructor(&tt->privates.varn);
return 0;
}
4. Perform initialization of all firstprivate fields (by simple copying for POD data, copy constructor calls for classes) + provide address of a destructor function after kmpc_omp_task_alloc() and before kmpc_omp_task() calls.
kmp_task_t *new_task = __kmpc_omp_task_alloc(ident_t *, kmp_int32 gtid, kmp_int32 flags, size_t sizeof_kmp_task_t, size_t sizeof_shareds, kmp_routine_entry_t *task_entry);
CopyConstructor(new_task->privates.var1, *new_task->shareds.var1_ref);
new_task->shareds.var1_ref = &new_task->privates.var1;
...
CopyConstructor(new_task->privates.varn, *new_task->shareds.varn_ref);
new_task->shareds.varn_ref = &new_task->privates.varn;
new_task->destructors = .omp_task_destructor.;
kmp_int32 __kmpc_omp_task(ident_t *, kmp_int32 gtid, kmp_task_t *new_task)
Differential Revision: http://reviews.llvm.org/D9370
llvm-svn: 236479
For tasks codegen for private/firstprivate variables are different rather than for other directives.
1. Build an internal structure of privates for each private variable:
struct .kmp_privates_t. {
Ty1 var1;
...
Tyn varn;
};
2. Add a new field to kmp_task_t type with list of privates.
struct kmp_task_t {
void * shareds;
kmp_routine_entry_t routine;
kmp_int32 part_id;
kmp_routine_entry_t destructors;
.kmp_privates_t. privates;
};
3. Create a function with destructors calls for all privates after end of task region.
kmp_int32 .omp_task_destructor.(kmp_int32 gtid, kmp_task_t *tt) {
~Destructor(&tt->privates.var1);
...
~Destructor(&tt->privates.varn);
return 0;
}
4. Perform default initialization of all private fields (no initialization for POD data, default constructor calls for classes) + provide address of a destructor function after kmpc_omp_task_alloc() and before kmpc_omp_task() calls.
kmp_task_t *new_task = __kmpc_omp_task_alloc(ident_t *, kmp_int32 gtid, kmp_int32 flags, size_t sizeof_kmp_task_t, size_t sizeof_shareds, kmp_routine_entry_t *task_entry);
DefaultConstructor(new_task->privates.var1);
new_task->shareds.var1_ref = &new_task->privates.var1;
...
DefaultConstructor(new_task->privates.varn);
new_task->shareds.varn_ref = &new_task->privates.varn;
new_task->destructors = .omp_task_destructor.;
kmp_int32 __kmpc_omp_task(ident_t *, kmp_int32 gtid, kmp_task_t *new_task)
Differential Revision: http://reviews.llvm.org/D9322
llvm-svn: 236207
Emit the following code for 'taskwait' directive within tied task:
call i32 @__kmpc_omp_taskwait(<loc>, i32 <thread_id>);
Differential Revision: http://reviews.llvm.org/D9245
llvm-svn: 235836
Emit a code for reduction clause. Next code should be emitted for reductions:
static kmp_critical_name lock = { 0 };
void reduce_func(void *lhs[<n>], void *rhs[<n>]) {
*(Type0*)lhs[0] = ReductionOperation0(*(Type0*)lhs[0], *(Type0*)rhs[0]);
...
*(Type<n>-1*)lhs[<n>-1] =
ReductionOperation<n>-1(*(Type<n>-1*)lhs[<n>-1],
*(Type<n>-1*)rhs[<n>-1]);
}
...
void *RedList[<n>] = {&<RHSExprs>[0], ..., &<RHSExprs>[<n>-1]};
switch (__kmpc_reduce{_nowait}(<loc>, <gtid>, <n>, sizeof(RedList), RedList, reduce_func, &<lock>)) {
case 1:
<LHSExprs>[0] = ReductionOperation0(*<LHSExprs>[0], *<RHSExprs>[0]);
...
<LHSExprs>[<n>-1] = ReductionOperation<n>-1(*<LHSExprs>[<n>-1], *<RHSExprs>[<n>-1]);
__kmpc_end_reduce{_nowait}(<loc>, <gtid>, &<lock>);
break;
case 2:
Atomic(<LHSExprs>[0] = ReductionOperation0(*<LHSExprs>[0], *<RHSExprs>[0]));
...
Atomic(<LHSExprs>[<n>-1] = ReductionOperation<n>-1(*<LHSExprs>[<n>-1], *<RHSExprs>[<n>-1]));
break;
default:;
}
Reduction variables are a kind of a private variables, they have private copies, but initial values are chosen in accordance with the reduction operation.
If sections directive has only single section, then original shared variables are used instead with barrier at the end of the directive.
Differential Revision: http://reviews.llvm.org/D9242
llvm-svn: 235835
#pragma omp sections lastprivate(<var>)
<BODY>;
This construct is translated into something like:
<last_iter> = alloca i32
<init for lastprivates>;
<last_iter> = 0
; No initializer for simple variables or a default constructor is called for objects.
; For arrays perform element by element initialization by the call of the default constructor.
...
OMP_FOR_START(...,<last_iter>, ..); sets <last_iter> to 1 if this is the last iteration.
<BODY>
...
OMP_FOR_END
if (<last_iter> != 0) {
<final copy for lastprivate>; Update original variable with the lastprivate value.
}
call __kmpc_cancel_barrier() ; an implicit barrier to avoid possible data race.
If there is only one section, there is no special code generation, original shared variables are used + barrier is emitted at the end of the directive.
Differential Revision: http://reviews.llvm.org/D9240
llvm-svn: 235834
If there are 2 or more sections in a 'section' directive the following code is generated:
<default init for privates>
@__kmpc_for_static_init_4();
<BODY for sections directive>
@__kmpc_for_static_fini()
If there is only one section, the following code is generated:
if (@__kmpc_single()) {
<default init for privates>
@__kmpc_end_single();
}
Differential Revision: http://reviews.llvm.org/D9239
llvm-svn: 235833
Emit the following code for 'single' directive with 'private' clause:
if (@__kmpc_single()) {
<default init for privates>
@__kmpc_end_single();
}
Differential Revision: http://reviews.llvm.org/D9238
llvm-svn: 235832
Emit the following code for 'single' directive with 'firtstprivate' clause:
if (@__kmpc_single()) {
<init for firstprivates>
@__kmpc_end_single();
}
@__kmpc_cancel_barrier(); // To avoid data race in firstprivate init
Differential Revision: http://reviews.llvm.org/D9223
llvm-svn: 235694
Runtime function for 'copyprivate' directive generates implicit barriers, so no need to emit it.
Differential Revision: http://reviews.llvm.org/D9215
llvm-svn: 235692
If there are 2 or more sections in a 'section' directive the following code is generated:
<init for firstprivates>
@__kmpc_cancel_barrier();// To avoid data race in firstprivate init
@__kmpc_for_static_init_4();
<BODY for sections directive>
@__kmpc_for_static_fini()
If there is only one section, the following code is generated:
if (@__kmpc_single()) {
<init for firstprivates>
@__kmpc_end_single();
}
@__kmpc_cancel_barrier(); // To avoid data race in firstprivate init
Differential Revision: http://reviews.llvm.org/D9214
llvm-svn: 235691
The RegionCounter type does a lot of legwork, but most of it is only
meaningful within the implementation of CodeGenPGO. The uses elsewhere
in CodeGen generally just want to increment or read counters, so do
that directly.
llvm-svn: 235664
Adds codegen for 'atomic capture' constructs with the following forms of expressions/statements:
v = x binop= expr;
v = x++;
v = ++x;
v = x--;
v = --x;
v = x = x binop expr;
v = x = expr binop x;
{v = x; x = binop= expr;}
{v = x; x++;}
{v = x; ++x;}
{v = x; x--;}
{v = x; --x;}
{x = x binop expr; v = x;}
{x binop= expr; v = x;}
{x++; v = x;}
{++x; v = x;}
{x--; v = x;}
{--x; v = x;}
{x = x binop expr; v = x;}
{x = expr binop x; v = x;}
{v = x; x = expr;}
If x and expr are integer and binop is associative or x is a LHS in a RHS of the assignment expression, and atomics are allowed for type of x on the target platform atomicrmw instruction is emitted.
Otherwise compare-and-swap sequence is emitted.
Update of 'v' is not required to be be atomic with respect to the read or write of the 'x'.
bb:
...
atomic load <x>
cont:
<expected> = phi [ <x>, label %bb ], [ <new_failed>, %cont ]
<desired> = <expected> binop <expr>
<res> = cmpxchg atomic &<x>, desired, expected
<new_failed> = <res>.field1;
br <res>field2, label %exit, label %cont
exit:
atomic store <old/new x>, <v>
...
Differential Revision: http://reviews.llvm.org/D9049
llvm-svn: 235573
If condition evaluates to true, the code executes task by calling @__kmpc_omp_task() runtime function.
If condition evaluates to false, the code executes serial version of the code by executing the following code:
call void @__kmpc_omp_task_begin_if0(<loc>, <threadid>, <task_t_ptr, returned by @__kmpc_omp_task_alloc()>);
proxy_task_entry(<gtid>, <task_t_ptr, returned by @__kmpc_omp_task_alloc()>);
call void @__kmpc_omp_task_complete_if0(<loc>, <threadid>, <task_t_ptr, returned by @__kmpc_omp_task_alloc()>);
Also it checks if the condition is constant and if it is constant it evaluates its value and then generates either parallel version of the code (if the condition evaluates to true), or the serial version of the code (if the condition evaluates to false).
Differential Revision: http://reviews.llvm.org/D9143
llvm-svn: 235507
This patch generates helper variables which used as a private copies of the corresponding original variables inside an OpenMP 'for' directive. These generated variables are initialized by default (with the default constructor, if any). In OpenMP region references to original variables are replaced by the references to these private helper variables.
Differential Revision: http://reviews.llvm.org/D9106
llvm-svn: 235503
Patch fixes bugs in codegen for loops with unsigned counters and zero trip count. Previously preconditions for all loops were built using logic (Upper - Lower) > 0. But if the loop is a loop with zero trip count, then Upper - Lower is < 0 only for signed integer, for unsigned we're running into an underflow situation.
In this patch we're using original Lower<Upper condition to check that loop body can be executed at least once. Also this allows to skip code generation for loops, if it is known that preconditions for the loop are always false.
Differential Revision: http://reviews.llvm.org/D9103
llvm-svn: 235500
Add codegen for 'ordered' directive:
__kmpc_ordered(ident_t *, gtid);
<associated statement>;
__kmpc_end_ordered(ident_t *, gtid);
Also for 'for' directives with the dynamic scheduling and an 'ordered' clause added a call to '__kmpc_dispatch_fini_(4|8)[u]()' function after increment expression for loop control variable:
while(__kmpc_dispatch_next(&LB, &UB)) {
idx = LB;
while (idx <= UB) { BODY; ++idx;
__kmpc_dispatch_fini_(4|8)[u](); // For ordered loops only.
} // inner loop
}
Differential Revision: http://reviews.llvm.org/D9070
llvm-svn: 235496
Emits the following code for the clause at the beginning of the outlined function for implicit threads:
if (<not a master thread>) {
...
<thread local copy of var> = <master thread local copy of var>;
...
}
<sync point>;
Checking for a non-master thread is performed by comparing of the address of the thread local variable with the address of the master's variable. Master thread always uses original variables, so you always know the address of the variable in the master thread.
Differential Revision: http://reviews.llvm.org/D9026
llvm-svn: 235075
#pragma omp for lastprivate(<var>)
for (i = a; i < b; ++b)
<BODY>;
This construct is translated into something like:
<last_iter> = alloca i32
<lastprivate_var> = alloca <type>
<last_iter> = 0
; No initializer for simple variables or a default constructor is called for objects.
; For arrays perform element by element initialization by the call of the default constructor.
...
OMP_FOR_START(...,<last_iter>, ..); sets <last_iter> to 1 if this is the last iteration.
<BODY>
...
OMP_FOR_END
if (<last_iter> != 0) {
<var> = <lastprivate_var> ; Update original variable with the lastprivate value.
}
call __kmpc_cancel_barrier() ; an implicit barrier to avoid possible data race.
Differential Revision: http://reviews.llvm.org/D8658
llvm-svn: 235074
Adds proper codegen for 'firstprivate' clause in for directive. Initially codegen for 'firstprivate' clause was implemented for 'parallel' directive only.
Also this patch emits sync point only after initialization of firstprivate variables, not all private variables. This sync point is not required for privates, lastprivates etc., only for initialization of firstprivate variables.
Differential Revision: http://reviews.llvm.org/D8660
llvm-svn: 234978
Fixed a bug with codegen of variables with array types specified in 'copyprivate' clause of 'single' directive.
Differential Revision: http://reviews.llvm.org/D8914
llvm-svn: 234856
Adds atomic update codegen for the following forms of expressions:
x binop= expr;
x++;
++x;
x--;
--x;
x = x binop expr;
x = expr binop x;
If x and expr are integer and binop is associative or x is a LHS in a RHS of the assignment expression, and atomics are allowed for type of x on the target platform atomicrmw instruction is emitted.
Otherwise compare-and-swap sequence is emitted:
bb:
...
atomic load <x>
cont:
<expected> = phi [ <x>, label %bb ], [ <new_failed>, %cont ]
<desired> = <expected> binop <expr>
<res> = cmpxchg atomic &<x>, desired, expected
<new_failed> = <res>.field1;
br <res>field2, label %exit, label %cont
exit:
...
Differential Revision: http://reviews.llvm.org/D8536
llvm-svn: 233513
Replace boolean IsExplicit parameter of OpenMPRuntime::emitBarrierCall() method by OpenMPDirectiveKind Kind for better compatibility with the runtime library. Also add processing of 'nowait' clause on worksharing directives.
Differential Revision: http://reviews.llvm.org/D8659
llvm-svn: 233511
If there is at least one 'copyprivate' clause is associated with the single directive, the following code is generated:
```
i32 did_it = 0; \\ for 'copyprivate' clause
if(__kmpc_single(ident_t *, gtid)) {
SingleOpGen();
__kmpc_end_single(ident_t *, gtid);
did_it = 1; \\ for 'copyprivate' clause
}
<copyprivate_list>[0] = &var0;
...
<copyprivate_list>[n] = &varn;
call __kmpc_copyprivate(ident_t *, gtid, <copyprivate_list_size>,
<copyprivate_list>, <copy_func>, did_it);
...
void<copy_func>(void *LHSArg, void *RHSArg) {
Dst = (void * [n])(LHSArg);
Src = (void * [n])(RHSArg);
Dst[0] = Src[0];
... Dst[n] = Src[n];
}
```
All list items from all 'copyprivate' clauses are gathered into single <copyprivate list> (<copyprivate_list_size> is a size in bytes of this list) and <copy_func> is used to propagate values of private or threadprivate variables from the 'single' region to other implicit threads from outer 'parallel' region.
Differential Revision: http://reviews.llvm.org/D8410
llvm-svn: 232932
The linear variable is privatized (similar to 'private') and its
value on current iteration is calculated, similar to the loop
counter variables.
Differential revision: http://reviews.llvm.org/D8375
llvm-svn: 232890
This patch allows using of ExprWithCleanups expressions and other complex expressions in 'omp atomic' construct
Differential Revision: http://reviews.llvm.org/D8200
llvm-svn: 231905
The task region is emmitted in several steps:
Emit a call to kmp_task_t *__kmpc_omp_task_alloc(ident_t *, kmp_int32 gtid, kmp_int32 flags, size_t sizeof_kmp_task_t, size_t sizeof_shareds, kmp_routine_entry_t *task_entry).
Here task_entry is a pointer to the function:
kmp_int32 .omp_task_entry.(kmp_int32 gtid, kmp_task_t *tt) {
TaskFunction(gtid, tt->part_id, tt->shareds);
return 0;
}
Copy a list of shared variables to field shareds of the resulting structure kmp_task_t returned by the previous call (if any).
Copy a pointer to destructions function to field destructions of the resulting structure kmp_task_t.
Emit a call to kmp_int32 __kmpc_omp_task(ident_t *, kmp_int32 gtid, kmp_task_t *new_task), where new_task is a resulting structure from previous items.
Differential Revision: http://reviews.llvm.org/D7560
llvm-svn: 231762
Patch adds proper generation of debug info for all OpenMP regions. Also, all OpenMP regions are generated in a termination scope, because standard does not allow to throw exceptions out of structured blocks, associated with the OpenMP regions
Differential Revision: http://reviews.llvm.org/D7935
llvm-svn: 231757
This reverts commit r231752.
It was failing to link with cmake:
lib64/libclangCodeGen.a(CGOpenMPRuntime.cpp.o):/home/espindola/llvm/llvm/tools/clang/lib/CodeGen/CGOpenMPRuntime.cpp:function clang::CodeGen::InlinedOpenMPRegionRAII::~InlinedOpenMPRegionRAII(): error: undefined reference to 'clang::CodeGen::EHScopeStack::popTerminate()'
clang-3.7: error: linker command failed with exit code 1 (use -v to see invocation)
llvm-svn: 231754
Patch adds proper generation of debug info for all OpenMP regions. Also, all OpenMP regions are generated in a termination scope, because standard does not allow to throw exceptions out of structured blocks, associated with the OpenMP regions
Differential Revision: http://reviews.llvm.org/D7935
llvm-svn: 231752
For global reg lvalue - use regular store through global register.
For simple lvalue - use simple atomic store.
For bitfields, vector element, extended vector elements - the original value of the whole storage (for vector elements) or of some aligned value (for bitfields) is atomically read, the part of this value for the given lvalue is modified and then use atomic compare-and-exchange operation to try to atomically write modified value (if it was not modified).
Also, changes in this patch fix the bug for '#pragma omp atomic read' applied to extended vector elements.
Differential Revision: http://reviews.llvm.org/D7369
llvm-svn: 230736
The /volatile:ms semantics turn volatile loads and stores into atomic
acquire and release operations. This distinction is important because
volatile memory operations do not form a happens-before relationship
with non-atomic memory. This means that a volatile store is not
sufficient for implementing a mutex unlock routine.
Differential Revision: http://reviews.llvm.org/D7580
llvm-svn: 229082
This patch emits the following code for the single directive:
#pragma omp single
<body>
<---->
if(__kmpc_single(...)) {
<body>
__kmpc_end_single(...);
}
Differential Revision: http://reviews.llvm.org/D7045
llvm-svn: 228275
For 'taskyield' directive emit call to kmp_int32 __kmpc_omp_taskyield(ident_t *,
kmp_int32 global_tid, int end_part); runtime function call with end_part arg set
to 0 (it is ignored).
Differential Revision: http://reviews.llvm.org/D7047
llvm-svn: 228272
Alexey Bataev