[AMDGPU] VGPR instruction placement should be aware of exec mask prol…#175080
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carlobertolli wants to merge 1 commit intollvm:mainfrom
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[AMDGPU] VGPR instruction placement should be aware of exec mask prol…#175080carlobertolli wants to merge 1 commit intollvm:mainfrom
carlobertolli wants to merge 1 commit intollvm:mainfrom
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…ogues. This patch changes the insertion logic for VGPR modifying instruction to skip to after the exec mask is reset, if such an instruction is present in the basic block. It is used to prevent placement of scratch store/load for VGPRs before the exec mask is reset on AMDGPUs.
cdevadas
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Jan 9, 2026
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Introducing another target hook while retaining isBasicBlockPrologue would increase the complexity further. This approach doesn't seem like a favorable one for addressing our problem.
| /// a basic block. This is used by the register allocator's live range | ||
| /// splitting logic. | ||
| virtual MachineBasicBlock::iterator | ||
| getExecAwareInsertPoint(MachineBasicBlock &MBB, Register Reg) const; |
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Should use a generic name without any target-dependent register details in a common file.
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Alternative approach is now approved: https://github.com/llvm/llvm-project/pull/117544 closing this draft PR. |
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…ogues.
This patch changes the insertion logic for VGPR modifying instruction to skip to after the exec mask is reset, if such an instruction is present in the basic block. It is used to prevent placement of scratch store/load for VGPRs before the exec mask is reset on AMDGPUs.