• More ISA Differences Come To Light With The New AMD GFX1170 “RDNA 4m” Earlier this month we spotted the addition of a new GFX1170 GPU target in the AMDGPU LLVM back-end. • Making this GFX1170 target interesting is that its marked as an APU/SoC part with “RDNA 4m” while being part of the GFX11 series. • The GFX11 series is for RDNA3, GFX115x is for RDNA 3.5, and GFX12 is RDNA4. • More ISA changes have now been committed to the AMDGPU LLVM back-end that make a few more instruction differences better aligned with RDNA4. • The GFX1170 target in the LLVM AMDGPU code began with just a few feature differences over existing GFX3 targets, most notably was FP8/BF8 conversion support added. • In the time since that initial activity, more differences are now indicated in the latest LLVM Git code.

Article Summaries:

  • AMD has added a new GFX1170 target to the AMDGPU LLVM back‑end, labeling it “RDNA 4m” even though it sits in the GFX11 (RDNA 3) series. The update introduces several ISA changes that bring the GPU’s instruction set closer to RDNA 4, including new WMMA128b and SWMMAC instructions and the removal of the V_DOT2ACC_F32_F16 dot‑product instruction. Additional patches drop the DX10_CLAMP and IEEE mode bits, which RDNA 4 already omitted. These modifications aim to improve AI/ML and compute workloads, but it remains unclear which APUs or SoCs will eventually ship with this RDNA 4m graphics IP.

Sources: