Configure.cmake: improve RVV1 check #602
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To test for the RISC-V vector extension (RVV), we currently run two small programs -- one for each value of LMUL=1,2 -- that use some vector intrinsics from the v0.11.x draft of the intrinsics spec. The library itself however needs newer intrinsics than the ones that we test for. This can lead to a problem because GCC 13 supports the intrinsics that we test for, but not (all of) the ones we intend to use. In short, the build can fail with GCC 13: shibatch#579 This commit changes the detection mechanism. Instead of compiling a program that makes use of the intrinsics, we now just check the two values, __riscv_v and __riscv_v_intrinsic, to ensure that we have version 1.0 of the vector extension and version 0.12 of the intrinsics. These should be the stable versions of each. Note: the "m1" and "m2" checks are now identical because they are both covered by the official spec. Fixes shibatch#579
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ericlove
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Nov 5, 2024
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To test for RVV1 support, we currently run a small program that uses some vector intrinsics from the v0.11.x draft of the RVV standard. The library itself however needs newer intrinsics than the ones that we test for. This can lead to a problem because GCC 13 supports the intrinsics that we test for, but not (all of) the ones we intend to use. In short, the build can fail with GCC 13: #579
This commit changes the detection mechanism. Instead of compiling a program that makes use of the intrinsics, we now just check the two values,
__riscv_vand__riscv_v_intrinsic, to ensure that we have version 1.0 of RVV and version 0.12 of the intrinsics. According to the intrinsics spec, https://github.com/riscv-non-isa/rvv-intrinsic-doc, these are the stable versions.