diff --git a/llvm/docs/AMDGPUUsage.rst b/llvm/docs/AMDGPUUsage.rst --- a/llvm/docs/AMDGPUUsage.rst +++ b/llvm/docs/AMDGPUUsage.rst @@ -8240,23 +8240,27 @@ * GFX6-GFX8: M0 * All SGPR registers except the clobbered registers of SGPR4-31. * VGPR40-47 - VGPR56-63 - VGPR72-79 - VGPR88-95 - VGPR104-111 - VGPR120-127 - VGPR136-143 - VGPR152-159 - VGPR168-175 - VGPR184-191 - VGPR200-207 - VGPR216-223 - VGPR232-239 - VGPR248-255 - - *Except the argument registers, the VGPR clobbered and the preserved - registers are intermixed at regular intervals in order to - get a better occupancy.* + * VGPR56-63 + * VGPR72-79 + * VGPR88-95 + * VGPR104-111 + * VGPR120-127 + * VGPR136-143 + * VGPR152-159 + * VGPR168-175 + * VGPR184-191 + * VGPR200-207 + * VGPR216-223 + * VGPR232-239 + * VGPR248-255 + + .. note:: + + Except the argument registers, the VGPRs clobbered and the preserved + registers are intermixed at regular intervals in order to keep a + similar ratio independent of the number of allocated VGPRs. + + * Lanes of all VGPRs that are inactive at the call site. For the AMDGPU backend, an inter-procedural register allocation (IPRA) optimization may mark some of clobbered SGPR and VGPR registers as