Fixed Issues / Improvements

• Fix get_sub_group_id builtin handling
• Remove unused GTPin vISA option
• Further refactoring of vISA attributes
• vISA will use dispatch SIMD size from an attribute instead of scanning all instructions
• Fix to handle a infinite loop stuck issue leading to compilation hang
• Fix the performance regression caused by scalar suppression
• Refactor pixel shader code gen to avoid hard-coding SIMD size and GRF size
• Fix to SIMD16 shuffle down
• Add possibility to control partial component packing via shader metadata
• Fix sub_group_clustered_reduce_* on 64-bit types
• Extend LVN to detect more instructions
• Use attributes to get attributes names instead of hard-coding them wherever possible
• Added SimdSize kernel attribute (not used yet)
• Added sin/cos to sinpi/cospi optimization to improve performance
• Fixed the BCR static check
• Added getPlatform() function to IR_Builder and G4_INST
• Fixes in L0 tests
• Added vISA documentation
• Minor cleanup for G4_Declare
• Fixes for getAttributeID (searching all attributes instead of only kernels')
• Fix for subgroup_scan_exclusive for char and short
• Updated fcl interface to latest
• Added include guards, needed overrides, and some miscellaneous path fixes
• Added a debug knob to change the max block push constants threshold.
• Other minor bugfixes and improvements

Ubuntu 18.04 binary packages for LLVM10/Clang10 are included.