[PATCH] D91308: AMDGPU: Split large offsets when selecting global saddr mode

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

rampitec added inline comments.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp:1843
 
     // TODO: Could split larger constant into VGPR offset.
     if (TII->isLegalFLATOffset(COffsetVal, AMDGPUAS::GLOBAL_ADDRESS, true)) {
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This todo is not relevant anymore.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp:1849
+      SDLoc SL(N);
+      // saddr + large_offset -> saddr + (voffset = large_offset & ~MaxOffset) +
+      //                         (large_offset & MaxOffset);
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If you have several consequtive loads this logic will result in reinitialization of vaddr before each load. You could probably mask few low bits in MaxOffset for this purpose to create a window of instructions which can use the same base registers.


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  https://reviews.llvm.org/D91308/new/

https://reviews.llvm.org/D91308