OpenMP Optimization Remarks

The OpenMP-Aware optimization pass is able to generate compiler remarks for performed and missed optimisations. To emit them, pass these options to the Clang invocation: -Rpass=openmp-opt -Rpass-analysis=openmp-opt -Rpass-missed=openmp-opt. For more information and features of the remark system, consult the clang documentation:

OpenMP Remarks

Diagnostics Number

Diagnostics Kind

Diagnostics Description

OMP100

Analysis

Potentially unknown OpenMP target region caller.

OMP101

Analysis

Parallel region is used in unknown / unexpected ways. Will not attempt to rewrite the state machine.

OMP102

Analysis

Parallel region is not called from a unique kernel. Will not attempt to rewrite the state machine.

OMP110

Optimization

Moving globalized variable to the stack.

OMP111

Optimization

Replaced globalized variable with X bytes of shared memory.

OMP112

Missed

Found thread data sharing on the GPU. Expect degraded performance due to data globalization.

OMP113

Missed

Could not move globalized variable to the stack. Variable is potentially captured in call. Mark parameter as __attribute__((noescape)) to override.

OMP120

Optimization

Transformed generic-mode kernel to SPMD-mode.

OMP121

Analysis

Value has potential side effects preventing SPMD-mode execution. Add [[omp::assume("ompx_spmd_amenable")]] to the called function to override.

OMP130

Optimization

Removing unused state machine from generic-mode kernel.

OMP131

Optimization

Rewriting generic-mode kernel with a customized state machine.

OMP132

Analysis

Generic-mode kernel is executed with a customized state machine that requires a fallback.

OMP133

Analysis

Call may contain unknown parallel regions. Use [[omp::assume(“omp_no_parallelism”)]] to override.

OMP140

Analysis

Could not internalize function. Some optimizations may not be possible.

OMP150

Optimization

Parallel region merged with parallel region at <location>.

OMP160

Optimization

Removing parallel region with no side-effects.

OMP170

Optimization

OpenMP runtime call <call> deduplicated.

OMP180

Optimization

Replacing OpenMP runtime call <call> with <value>.

OMP190

Optimization

Redundant barrier eliminated. (device only)