[llvm-bugs] [Bug 43887] New: Vectorization failure due to SimplifyCFG's hoisting of identical load from two BB's

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=43887

            Bug ID: 43887
           Summary: Vectorization failure due to SimplifyCFG's hoisting of
                    identical load from two BB's
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: lebedev.ri at gmail.com
                CC: llvm-bugs at lists.llvm.org

https://godbolt.org/z/7tG__b

The first load is identical for both of the basic blocks,
and if we look at -print-after-all, until `Simplify the CFG` both BB's had
that load, but SimplifyCFG hoists it from both of the blocks.
And SLPVectrorizer only analyzes one basic block at the time, so

SLP: Gathering due to C,S,B,O.

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