[llvm-bugs] [Bug 43968] New: [X86] Invalid code generated for shufflevector + extractelement

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=43968

            Bug ID: 43968
           Summary: [X86] Invalid code generated for shufflevector +
                    extractelement
           Product: libraries
           Version: trunk
          Hardware: All
                OS: All
            Status: NEW
          Keywords: miscompilation
          Severity: normal
          Priority: P
         Component: Backend: X86
          Assignee: unassignedbugs at nondot.org
          Reporter: nunoplopes at sapo.pt
                CC: craig.topper at gmail.com, liuz at cs.utah.edu,
                    llvm-bugs at lists.llvm.org, llvm-dev at redking.me.uk,
                    regehr at cs.utah.edu, spatel+llvm at rotateright.com

define float @foo(i32 %a, float %in) {
  %1 = insertelement <4 x float> undef, float %in, i32 0
  %t6.i = shufflevector <4 x float> %1, <4 x float> undef, <4 x i32> <i32
undef, i32 0, i32 0, i32 0>
  %val = extractelement <4 x float> %t6.i, i32 1
  ret float %val
}


llc gives:
foo:                                    # @foo
        ret


It should return %in.

https://godbolt.org/z/Ej_CKQ

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