[llvm] [InstCombine] Copy flags of extractelement for extelt -> icmp combine (PR #86366)

[Thorsten Schütt via llvm-commits]

================
@@ -341,6 +341,20 @@ define i1 @extractelt_vector_fcmp_constrhs_dynidx(<2 x float> %arg, i32 %idx) {
   ret i1 %ext
 }
 
+define i1 @extractelt_vector_fcmp_copy_flags(<4 x float> %x, <4 x i1> %y) {
+; CHECK-LABEL: @extractelt_vector_fcmp_copy_flags(
+; CHECK-NEXT:    [[TMP1:%.*]] = extractelement <4 x float> [[X:%.*]], i64 2
+; CHECK-NEXT:    [[TMP2:%.*]] = fcmp nsz arcp oeq float [[TMP1]], 0.000000e+00
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <4 x i1> [[Y:%.*]], i64 2
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[TMP2]], [[TMP3]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = fcmp nsz arcp oeq <4 x float> %x, zeroinitializer
+  %and = and <4 x i1> %cmp, %y
----------------
tschuett wrote:

Why do need the and?

https://github.com/llvm/llvm-project/pull/86366