[llvm-bugs] [Bug 39658] New: X86CondBrFolding causes miscompile

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=39658

            Bug ID: 39658
           Summary: X86CondBrFolding causes miscompile
           Product: new-bugs
           Version: trunk
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: max.kazantsev at azul.com
                CC: htmldeveloper at gmail.com, llvm-bugs at lists.llvm.org

Created attachment 21116
  --> https://bugs.llvm.org/attachment.cgi?id=21116&action=edit
test.ll

X86CondBrFolding pass first introduced in patch
https://reviews.llvm.org/rL343993 has caused incorrect calculations on one of
our Java tests. The calculation resuit is OK when this transform is turned off
by setting the option x86-condbr-folding to 0.

I haven't figured out what exactly is wrong in what this pass is doing.

To reproduce, run llc on the test.ll in attachment.

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