Commit 85ad5663 authored by Huber, Joseph's avatar Huber, Joseph
Browse files

[OpenMP] Avoid calling `isSPMDMode` during RT initialization 

Until we hit the first barrier we should not call `mapping::isSPMDMode`
with all threads. Instead, we now have (and use during initialization) a
`mapping::isMainThreadInGenericMode` overload that takes the known
SPMD-mode state and one that queries it.

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D111381
parent 222305d6

openmp/libomptarget/DeviceRTL/include/Mapping.h

+1 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ bool isGenericMode(); 


/// Return true if the executing thread is the main thread in generic mode.

bool isMainThreadInGenericMode();

bool isMainThreadInGenericMode(bool IsSPMD);



/// Return true if the executing thread has the lowest Id of the active threads

/// in the warp.

openmp/libomptarget/DeviceRTL/src/Kernel.cpp

+1 −1
Original line number Diff line number Diff line
@@ -81,7 +81,7 @@ int32_t __kmpc_target_init(IdentTy *Ident, int8_t Mode, 
    return -1;

  }



  if (mapping::isMainThreadInGenericMode())

  if (mapping::isMainThreadInGenericMode(IsSPMD))

    return -1;



  if (UseGenericStateMachine)

openmp/libomptarget/DeviceRTL/src/Mapping.cpp

+6 −2
Original line number Diff line number Diff line
@@ -165,8 +165,8 @@ uint32_t getWarpSize() { return getGridValue().GV_Warp_Size; } 
} // namespace impl

} // namespace _OMP



bool mapping::isMainThreadInGenericMode() {

  if (mapping::isSPMDMode() || icv::Level)

bool mapping::isMainThreadInGenericMode(bool IsSPMD) {

  if (IsSPMD || icv::Level)

    return false;



  // Check if this is the last warp in the block.
@@ -175,6 +175,10 @@ bool mapping::isMainThreadInGenericMode() { 
  return mapping::getThreadIdInBlock() == MainTId;

}



bool mapping::isMainThreadInGenericMode() {

  return mapping::isMainThreadInGenericMode(mapping::isSPMDMode());

}



bool mapping::isLeaderInWarp() {

  __kmpc_impl_lanemask_t Active = mapping::activemask();

  __kmpc_impl_lanemask_t LaneMaskLT = mapping::lanemaskLT();

openmp/libomptarget/DeviceRTL/src/Reduction.cpp

+1 −1
Original line number Diff line number Diff line
@@ -72,7 +72,7 @@ static int32_t nvptx_parallel_reduce_nowait(int32_t TId, int32_t num_vars, 
                                            InterWarpCopyFnTy cpyFct,

                                            bool isSPMDExecutionMode, bool) {

  uint32_t BlockThreadId = mapping::getThreadIdInBlock();

  if (mapping::isMainThreadInGenericMode())

  if (mapping::isMainThreadInGenericMode(/* IsSPMD */ false))

    BlockThreadId = 0;

  uint32_t NumThreads = omp_get_num_threads();

  if (NumThreads == 1)