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:

• Clang options to emit optimization reports

• Clang diagnostic and remark flags

• The -foptimization-record-file flag and the -fsave-optimization-record flag

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 __attribute__((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 __attribute__((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)