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vint4::store(unsigned char*) wrote its 4 packed bytes via _mm_store_ss((float*)values), and several other partial stores cast to double*. The destination is often not aligned to that type (e.g. convert_type chunk boundaries with --threads 3), which is UB. GCC's intrinsic headers implement these as plain typed stores, so UBSan reports "store to misaligned address". Use memcpy (4-byte) or _mm_storel_epi64 (8-byte), which are alignment-agnostic and compile to the same movss/movlps. Also fix the NEON uint32_t* cast for consistency. Add simd_test coverage that stores to element-aligned but not SIMD-store-aligned addresses; fails under UBSan with GCC on x86 without this fix. Fixes AcademySoftwareFoundation#5560 Assisted-by: Claude Code / Claude Opus 5.5 Signed-off-by: Larry Gritz <lg@larrygritz.com>
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vint4::store(unsigned char*)wrote its 4 packed bytes via_mm_store_ss((float*)values), and several other partial stores cast to double*. The destination is often not aligned to that type (e.g. convert_type chunk boundaries with --threads 3), which is UB. GCC's intrinsic headers implement these as plain typed stores, so UBSan reports "store to misaligned address".Use memcpy (4-byte) or _mm_storel_epi64 (8-byte), which are alignment-agnostic and compile to the same movss/movlps. Also fix the NEON uint32_t* cast for consistency.
Add simd_test coverage that stores to element-aligned but not SIMD-store-aligned addresses; fails under UBSan with GCC on x86 without this fix.
Fixes #5560
Assisted-by: Claude Code / Claude Opus 5.5