[llvm-bugs] [Bug 31761] New: GVN incorrectly forwards a load across a clobbering store.

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=31761

            Bug ID: 31761
           Summary: GVN incorrectly forwards a load across a clobbering
                    store.
           Product: new-bugs
           Version: 3.9
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: mehdi.amini at apple.com
                CC: llvm-bugs at lists.llvm.org
    Classification: Unclassified

Created attachment 17896
  --> https://llvm.org/bugs/attachment.cgi?id=17896&action=edit
GVN Bug

See attached IR. This is a single-block sequence of:

  %0 = Load ptr    ; original load
  store null, ptr  ; clobber...
  %1 = load ptr    ; reload

The original value is forwarded to the user of the reload.

Reproduces on trunk with opt -gvn repro.ll

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