codegen: keep a symbolically-sized register array on the stack - #2504
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ThrudPrimrose wants to merge 6 commits into
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codegen: keep a symbolically-sized register array on the stack#2504ThrudPrimrose wants to merge 6 commits into
ThrudPrimrose wants to merge 6 commits into
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A StorageType.Register array whose size is symbolic was allocated on the heap with a warning. GCC, Clang and NVHPC all accept variable-length arrays, so it is now declared in place; allocation and deallocation share one predicate so they cannot disagree, and a VLA takes a memset rather than a brace initializer.
A VLA dies with its block, but Global, Persistent and External arrays are declared outside it -- codegen emits a program-level pointer for those, which the local declaration shadowed while leaving the pointer null.
… emitter MarkVLAArrays sets Data.vla on the symbolically-sized register arrays whose lifetime ends with the block they are declared in and whose size is already defined there; code generation reads the flag and nothing else. A size that only an interstate edge assigns splits the declaration from the allocation, and a VLA declared under that split shadows the SDFG-scope pointer, which stays null - the segfaulting case the earlier in-emitter predicate missed.
…declaration A size that only an interstate edge assigns makes framecode declare the pointer at SDFG scope and allocate in a later block; a VLA there shadows that pointer, which stays null - four tests segfaulted on it. declared_arrays already records that, so allocation and deallocation both ask the same predicate rather than a descriptor flag no pass can set correctly.
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StorageType.Registerarray whose size is symbolic was allocated on the heap with a warning, though GCC, Clang and NVHPC all accept variable-length arrays. It is now declared in place, with allocation and deallocation sharing one predicate so they cannot disagree.I think this is important because this means CloudSC and Velocity Tendencies code gets 2x faster!