[llvm] [VPlan] Remove hoisting to preheader in VPTransformState::get (PR #142594)

[Luke Lau via llvm-commits]

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@@ -97,8 +99,6 @@ define i8 @pr141968(i1 %cond, i8 %v) {
 ; CHECK:       [[PRED_SDIV_IF29]]:
 ; CHECK-NEXT:    br label %[[PRED_SDIV_CONTINUE30]]
 ; CHECK:       [[PRED_SDIV_CONTINUE30]]:
-; CHECK-NEXT:    [[BROADCAST_SPLATINSERT31:%.*]] = insertelement <16 x i8> poison, i8 [[V]], i64 0
-; CHECK-NEXT:    [[BROADCAST_SPLAT32:%.*]] = shufflevector <16 x i8> [[BROADCAST_SPLATINSERT31]], <16 x i8> poison, <16 x i32> zeroinitializer
 ; CHECK-NEXT:    [[PREDPHI:%.*]] = select <16 x i1> [[BROADCAST_SPLAT]], <16 x i8> zeroinitializer, <16 x i8> [[BROADCAST_SPLAT32]]
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lukel97 wrote:

I've opened https://github.com/llvm/llvm-project/pull/143798 for VPPredInstPHIRecipe, and reworked this PR to remove the SafeToHoist logic. 

In either case we still end up with the test diff in this test case, i.e. changing usesScalars doesn't seem to affect it.

https://github.com/llvm/llvm-project/pull/142594