[SLP][NFC]Update the test to simplify and avoid dead instruction

removal, NFC.

llvm/test/Transforms/SLPVectorizer/X86/PR35865.ll

@@ -1,11 +1,11 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -passes=slp-vectorizer < %s -S -o - -mtriple=x86_64-apple-macosx10.10.0 -mcpu=core2 | FileCheck %s
 
-define void @_Z10fooConvertPDv4_xS0_S0_PKS_() {
-; CHECK-LABEL: @_Z10fooConvertPDv4_xS0_S0_PKS_(
+define void @test(<16 x half> %v) {
+; CHECK-LABEL: @test(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = extractelement <16 x half> undef, i32 4
-; CHECK-NEXT:    [[TMP1:%.*]] = extractelement <16 x half> undef, i32 5
+; CHECK-NEXT:    [[TMP0:%.*]] = extractelement <16 x half> [[V:%.*]], i32 4
+; CHECK-NEXT:    [[TMP1:%.*]] = extractelement <16 x half> [[V]], i32 5
 ; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <2 x half> poison, half [[TMP0]], i32 0
 ; CHECK-NEXT:    [[TMP3:%.*]] = insertelement <2 x half> [[TMP2]], half [[TMP1]], i32 1
 ; CHECK-NEXT:    [[TMP4:%.*]] = fpext <2 x half> [[TMP3]] to <2 x float>
@@ -15,11 +15,11 @@ define void @_Z10fooConvertPDv4_xS0_S0_PKS_() {
 ; CHECK-NEXT:    ret void
 ;
 entry:
-  %0 = extractelement <16 x half> undef, i32 4
+  %0 = extractelement <16 x half> %v, i32 4
   %conv.i.4.i = fpext half %0 to float
   %1 = bitcast float %conv.i.4.i to i32
   %vecins.i.4.i = insertelement <8 x i32> undef, i32 %1, i32 4
-  %2 = extractelement <16 x half> undef, i32 5
+  %2 = extractelement <16 x half> %v, i32 5
   %conv.i.5.i = fpext half %2 to float
   %3 = bitcast float %conv.i.5.i to i32
   %vecins.i.5.i = insertelement <8 x i32> %vecins.i.4.i, i32 %3, i32 5