[PATCH] D111124: [Clang][OpenMP] Allow loop-transformations with template parameters.

[Michael Kruse via Phabricator via cfe-commits]

Meinersbur created this revision.
Meinersbur added reviewers: ABataev, jdenny.
Meinersbur added projects: OpenMP, clang.
Herald added subscribers: zzheng, guansong, yaxunl.
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Clang would reject

  #pragma omp for
  #pragma omp tile sizes(P)
  for (int i = 0; i < 128; ++i) {}

where P is a template parameter, but the loop itself is not template-dependent. Because P context-dependent, the TransformedStmt cannot be generated and therefore nullptr (until the template is instantiated). The OMPForDirective would still expect the a loop is the dependent context and trigger an error.

Fix by introducing a NumGeneratedLoops field to OMPLoopTransformation. This is used to distinguish the case where no TransformedStmt will be generated at all (e.g. `#pragma omp unroll full`) and template instantiation is needed. In the later case, delay resolving the iteration space like when the for-loop itself is template-dependent until the template instatiation.

A more radical solution would always delay the iteration space analysis until template instantiation, but would also break many test cases.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D111124

Files:
  clang/include/clang/AST/StmtOpenMP.h
  clang/lib/AST/StmtOpenMP.cpp
  clang/lib/Sema/SemaOpenMP.cpp
  clang/lib/Serialization/ASTReaderStmt.cpp
  clang/lib/Serialization/ASTWriterStmt.cpp
  clang/test/OpenMP/tile_ast_print.cpp
  clang/test/OpenMP/unroll_ast_print.cpp

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