[llvm] [VPlan] Run narrowInterleaveGroups during general VPlan optimizations. (PR #149706)

[via llvm-commits]

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@@ -8,15 +8,69 @@ target triple = "x86_64-unknown-linux"
 define void @test_4xi64(ptr noalias %data, ptr noalias %factor, i64 noundef %n) {
 ; CHECK-LABEL: define void @test_4xi64(
 ; CHECK-SAME: ptr noalias [[DATA:%.*]], ptr noalias [[FACTOR:%.*]], i64 noundef [[N:%.*]]) #[[ATTR0:[0-9]+]] {
-; CHECK-NEXT:  [[ENTRY:.*]]:
+; CHECK-NEXT:  [[ITER_CHECK:.*]]:
 ; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], 4
-; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[VEC_EPILOG_SCALAR_PH:.*]], label %[[VECTOR_MAIN_LOOP_ITER_CHECK:.*]]
+; CHECK:       [[VECTOR_MAIN_LOOP_ITER_CHECK]]:
+; CHECK-NEXT:    [[MIN_ITERS_CHECK1:%.*]] = icmp ult i64 [[N]], 16
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK1]], label %[[VEC_EPILOG_PH:.*]], label %[[VECTOR_PH:.*]]
 ; CHECK:       [[VECTOR_PH]]:
-; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], 4
-; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
+; CHECK-NEXT:    [[N_MOD_VF1:%.*]] = urem i64 [[N]], 16
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ayalz wrote:

Patch caused this testcase to change from (VF=4,) UF=1 to (VF=4,) UF=4?

https://github.com/llvm/llvm-project/pull/149706