initial selection DAG weirdness

out.txt

LLVM IR:

define <8 x double> @vsel_double8(<8 x double> %v1, <8 x double> %v2) {
  %vsel = select <8 x i1> <i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1 false, i1 false>, <8 x double> %v1, <8 x double> %v2
  ret <8 x double> %vsel
}


$ llc -mtriple=x86_64-apple-darwin -mcpu=corei7-avx -mattr=+avx -debug

=== vsel_double8
Initial selection DAG: BB#0 'vsel_double8:'
SelectionDAG has 25 nodes:
  0x103511f20: ch = EntryToken

  0x103840a50: i1 = Constant<-1>

  0x103840b58: i1 = Constant<0>

      0x103840a50: <multiple use>
      0x103840b58: <multiple use>
      0x103840b58: <multiple use>
      0x103840b58: <multiple use>
      0x103840a50: <multiple use>
      0x103840b58: <multiple use>
      0x103840b58: <multiple use>
      0x103840b58: <multiple use>
    0x103840c60: v8i1 = BUILD_VECTOR 0x103840a50, 0x103840b58, 0x103840b58, 0x103840b58, 0x103840a50, 0x103840b58, 0x103840b58, 0x103840b58 [ORD=2]

        0x103511f20: <multiple use>
        0x103840000: v4f64 = Register %vreg0

      0x103840108: v4f64,ch = CopyFromReg 0x103511f20, 0x103840000 [ORD=1]

        0x103511f20: <multiple use>
        0x103840210: v4f64 = Register %vreg1

      0x103840318: v4f64,ch = CopyFromReg 0x103511f20, 0x103840210 [ORD=1]

    0x103840840: v8f64 = concat_vectors 0x103840108, 0x103840318 [ORD=1]

        0x103511f20: <multiple use>
        0x103840420: v4f64 = Register %vreg2

      0x103840528: v4f64,ch = CopyFromReg 0x103511f20, 0x103840420 [ORD=1]

        0x103511f20: <multiple use>
        0x103840630: v4f64 = Register %vreg3

      0x103840738: v4f64,ch = CopyFromReg 0x103511f20, 0x103840630 [ORD=1]

    0x103840948: v8f64 = concat_vectors 0x103840528, 0x103840738 [ORD=1]

  0x103840d68: v8f64 = vselect 0x103840c60, 0x103840840, 0x103840948 [ORD=2]

  0x103842220: v4f64 = Register %YMM0

    0x103511f20: <multiple use>
    0x103842220: <multiple use>
      0x103840d68: <multiple use>
      0x103840e70: i64 = Constant<0>

    0x103841e00: v4f64 = extract_subvector 0x103840d68, 0x103840e70 [ORD=3]

  0x103842328: ch,glue = CopyToReg 0x103511f20, 0x103842220, 0x103841e00 [ORD=3]

  0x103842430: v4f64 = Register %YMM1

    0x103842328: <multiple use>
    0x103842430: <multiple use>
      0x103840d68: <multiple use>
      0x103841f08: i64 = Constant<4>

    0x103842010: v4f64 = extract_subvector 0x103840d68, 0x103841f08 [ORD=3]

    0x103842328: <multiple use>
  0x103842538: ch,glue = CopyToReg 0x103842328, 0x103842430, 0x103842010, 0x103842328:1 [ORD=3]

    0x103842538: <multiple use>
    0x103842118: i16 = TargetConstant<0>

    0x103842220: <multiple use>
    0x103842430: <multiple use>
    0x103842538: <multiple use>
  0x103842640: ch = X86ISD::RET_FLAG 0x103842538, 0x103842118, 0x103842220, 0x103842430, 0x103842538:1 [ORD=3]