[llvm-branch-commits] [llvm] release/22.x: [Hexagon] Fix AP register use-before-def and add MIR serialization for liveness tracking (#191010) (PR #192036)

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pkarveti wrote:

> it was the new MIR serialization and `BUILD_SHARED_LIBS=OFF` being missed initially that caught my eye, but I didn't look that closely

Thank you for the review - those are valid concerns. The MIR serialization was added to properly fix a liveness tracking issue: the initial workaround (commit 2e10b62) manually added AP to liveins, but only updated the current block without updating predecessors, violating liveness invariants. By serializing StackAlignBaseReg to MIR, the infrastructure automatically computes correct liveins for all blocks. You're absolutely right that missing BUILD_SHARED_LIBS=OFF initially was a testing gap on our part - it only manifests in static builds and @androm3da  follow-up (95af7de) fixed it by adding MIRParser to LINK_COMPONENTS.




https://github.com/llvm/llvm-project/pull/192036