Intel® DPC++ Compatibility Tool Developer Guide and Reference
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Visible to Intel only — GUID: GUID-C37BC552-B18B-4EE7-8CE7-2475AF5584B2
Incremental Migration
The Intel® DPC++ Compatibility Tool provides incremental migration, which automatically merges the results from multiple migrations into a single migrated project.
Incremental migration can be used to
migrate a CUDA* project incrementally, for example 10 files at a time
migrate new CUDA files into an already migrated project
migrate multiple code paths
Incremental migration is enabled by default. Disable incremental migration using the --no-incremental-migration option.
Example 1: Migrate a File with Conditional Compilation Code
This example shows incremental migration for a file sample1.cu that contains conditional compilation code. Content of sample1.cu:
#ifndef MACRO_A
... code path 1 ...
#elif MACRO_A == 1
... code path 2 ...
#else
... code path 3 ...
#endif
Incrementally migrate sample1.cu by executing the dpct command in the same working directory as the file:
Generate sample1.dp.cpp, which contains migrated code for code path 1:
dpct sample1.cu --out-root=out
Generate sample1.dp.cpp, which contains migrated code for code path 1 and code path 2:
dpct sample1.cu --out-root=out --extra-arg=”-DMACRO_A=1”
Generate sample1.dp.cpp, which contains migrated code for code path 1, code path 2, and code path 3:
dpct sample1.cu --out-root=out --extra-arg=”-DMACRO_A=2”
The result contains migrated code for each code path.
Example 2: Migrate a Header File Used by Multiple Source Files
This example shows the use of incremental migration for a header file that is included in several source files, each with a different macro definition.
Content of header file sample_inc.h:
#ifdef MACRO_A
... code path 1...
#else
... code path 2...
#endif
Content of source file sample2.cu:
#define MACRO_A
#include “sample_inc.h”
#undef MACRO_A
Content of source file sample3.cu:
#include “sample_inc.h”
Incrementally migrate the files by executing the dpct command in the same working directory as the files:
Generate sample2.dp.cpp and sample_inc.h, which contains migrated code for code path 1:
dpct sample2.cu --out-root=out
Generate sample3.dp.cpp and sample_inc.h, which contains migrated code for code path 1 and code path 2:
dpct sample3.cu --out-root=out
The result contains migrated code for each code path.
Limitations
Incremental migration will not be triggered in the following conditions:
Intel® DPC++ Compatibility Tool option --no-incremental-migration is specified.
Different versions of the Intel® DPC++ Compatibility Tool are used across multiple migration invocations.
Different options of the Intel® DPC++ Compatibility Tool are used across multiple migration invocations. If the Intel® DPC++ Compatibility Tool detects that a previous migration used a different option-set, the Intel® DPC++ Compatibility Tool will stop migration and exit.
The following options direct the Intel® DPC++ Compatibility Tool to generate different migrated code and may break incremental migration. Use the same values for these options across migration invocations to keep incremental migration working.
--always-use-async-handler
--assume-nd-range-dim
--comments
--custom-helper-name
--enable-ctad
--keep-original-code
--no-cl-namespace-inline
--no-dpcpp-extensions
--no-dry-pattern
--optimize-migration
-p
--process-all
--sycl-named-lambda
--use-experimental-features
--use-explicit-namespace
--usm-level
--vcxprojfile