[llvm-bugs] [Bug 34542] New: [AVX-512] Redundant instruction in Scatter sequence

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https://bugs.llvm.org/show_bug.cgi?id=34542

            Bug ID: 34542
           Summary: [AVX-512] Redundant instruction in Scatter sequence
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: Backend: X86
          Assignee: unassignedbugs at nondot.org
          Reporter: elena.demikhovsky at intel.com
                CC: llvm-bugs at lists.llvm.org

This is the IR code, which stores the same i32 value in 16 random locations:
define void @foo(i32 %x, <16 x i32*> %addr) {
  %y = insertelement <16 x i32>undef, i32 %x, i32 0
  %y1 = shufflevector <16 x i32>%y, <16 x i32> undef, <16 x i32>zeroinitializer
  br label %L
  L:
  call void @llvm.masked.scatter.v16i32.v16p0i32(<16 x i32> %y1, <16 x i32*>
%addr, i32 4, <16 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true,
i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1
true, i1 true>)
  ret void
}
declare void @llvm.masked.scatter.v16i32.v16p0i32(<16 x i32>, <16 x i32*>, i32,
<16 x i1>)

  vpbroadcastd    %edi, %zmm2
  kxnorw  %k0, %k0, %k1
  kxnorw  %k0, %k0, %k2
  vpscatterqd     %ymm2, (,%zmm0) {%k2}
  vextracti64x4   $1, %zmm2, %ymm0      <== This instruction is redundant.
  vpscatterqd     %ymm0, (,%zmm1) {%k1}

I checked the similar sequence with Store - it is ok, the problem is only in
the Scatter.

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