(The clang build fails for me locally, so this is based on built bot output and a guess as to root cause.)
f5fe849 made the execution of LAA conditional, so I'm guessing that's the root cause.
; CHECK-O: Running analysis: PostDominatorTreeAnalysis on main
; CHECK-O: Running analysis: DemandedBitsAnalysis on main
; CHECK-O: Running pass: LoopLoadEliminationPass on main
-; CHECK-O: Running analysis: LoopAccessAnalysis on Loop at depth 1 containing: %b
; CHECK-O: Running pass: InstCombinePass on main
; CHECK-O: Running pass: SimplifyCFGPass on main
; CHECK-O: Running pass: SLPVectorizerPass on main