[llvm] [VPlan] Handle single-scalar conds in VPWidenSelectRecipe. (PR #165506)

[Luke Lau via llvm-commits]

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@@ -150,10 +150,11 @@ define i32 @select_icmp_var_start_iv_trunc(i32 %N, i32 %start) #0 {
 ; CHECK-NEXT:    [[STEP_ADD:%.*]] = add <4 x i32> [[VEC_IND]], splat (i32 4)
 ; CHECK-NEXT:    [[STEP_ADD_2:%.*]] = add <4 x i32> [[STEP_ADD]], splat (i32 4)
 ; CHECK-NEXT:    [[STEP_ADD_3:%.*]] = add <4 x i32> [[STEP_ADD_2]], splat (i32 4)
-; CHECK-NEXT:    [[TMP3]] = select <4 x i1> [[TMP1]], <4 x i32> [[VEC_IND]], <4 x i32> [[VEC_PHI]]
-; CHECK-NEXT:    [[TMP4]] = select <4 x i1> [[TMP1]], <4 x i32> [[STEP_ADD]], <4 x i32> [[VEC_PHI2]]
-; CHECK-NEXT:    [[TMP5]] = select <4 x i1> [[TMP1]], <4 x i32> [[STEP_ADD_2]], <4 x i32> [[VEC_PHI3]]
-; CHECK-NEXT:    [[TMP6]] = select <4 x i1> [[TMP1]], <4 x i32> [[STEP_ADD_3]], <4 x i32> [[VEC_PHI4]]
+; CHECK-NEXT:    [[TMP2:%.*]] = extractelement <4 x i1> [[TMP1]], i32 0
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lukel97 wrote:

Looks like TMP1 is a cmp of a broadcast itself, not sure why it's not getting scalarized here.

https://github.com/llvm/llvm-project/pull/165506