Move test to tail-folding-vectorization-factor-1.ll

Needed to add -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue flag to run lines. Looks like the existing tests weren't necessarily tail folded?

Author: lukel97

llvm/test/Transforms/LoopVectorize/tail-folding-live-out-scalar-vf.ll

@@ -1,6 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes=loop-vectorize -force-vector-interleave=4 -pass-remarks='loop-vectorize' -disable-output -S 2>&1 | FileCheck %s --check-prefix=CHECK-REMARKS
-; RUN: opt < %s -passes=loop-vectorize -force-vector-interleave=4 -S | FileCheck %s
+; RUN: opt < %s -passes=loop-vectorize -force-vector-interleave=4 -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue -pass-remarks='loop-vectorize' -disable-output -S 2>&1 | FileCheck %s --check-prefix=CHECK-REMARKS
+; RUN: opt < %s -passes=loop-vectorize -force-vector-interleave=4 -prefer-predicate-over-epilogue=predicate-else-scalar-epilogue -S | FileCheck %s
 
 ; These tests are to check that fold-tail procedure produces correct scalar code when
 ; loop-vectorization is only unrolling but not vectorizing.
@@ -141,5 +141,61 @@ for.body:
   %cond = icmp eq ptr %ptr, %ptr2
   br i1 %cond, label %for.cond.cleanup, label %for.body
 }
+
+define i64 @live_out_scalar_vf(i64 %n) {
+; CHECK-LABEL: @live_out_scalar_vf(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[N:%.*]], 1
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[TMP0]], 16
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[TMP0]], 16
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[TMP0]], [[N_MOD_VF]]
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 0, i64 1, i64 2, i64 3>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[STEP_ADD:%.*]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
+; CHECK-NEXT:    [[STEP_ADD_2:%.*]] = add <4 x i64> [[STEP_ADD]], splat (i64 4)
+; CHECK-NEXT:    [[STEP_ADD_3:%.*]] = add <4 x i64> [[STEP_ADD_2]], splat (i64 4)
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 16
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[STEP_ADD_3]], splat (i64 4)
+; CHECK-NEXT:    [[TMP5:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP5]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement <4 x i64> [[STEP_ADD_3]], i32 3
+; CHECK-NEXT:    [[VECTOR_RECUR_EXTRACT_FOR_PHI:%.*]] = extractelement <4 x i64> [[STEP_ADD_3]], i32 2
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP0]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[SCALAR_RECUR_INIT:%.*]] = phi i64 [ [[VECTOR_RECUR_EXTRACT]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ]
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ]
+; CHECK-NEXT:    [[EXITVAL:%.*]] = phi i64 [ [[SCALAR_RECUR_INIT]], [[SCALAR_PH]] ], [ [[IV]], [[LOOP]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[EC:%.*]] = icmp eq i64 [[IV]], [[N]]
+; CHECK-NEXT:    br i1 [[EC]], label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[TMP19:%.*]] = phi i64 [ [[EXITVAL]], [[LOOP]] ], [ [[VECTOR_RECUR_EXTRACT_FOR_PHI]], [[MIDDLE_BLOCK]] ]
+; CHECK-NEXT:    ret i64 [[TMP19]]
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
+  ; Need to use a phi otherwise the header mask will use a
+  ; VPWidenCanonicalIVRecipe instead of a VPScalarIVStepsRecipe.
+  %exitval = phi i64 [ 0, %entry ], [ %iv, %loop ]
+  %iv.next = add i64 %iv, 1
+  %ec = icmp eq i64 %iv, %n
+  br i1 %ec, label %exit, label %loop
+
+exit:
+  ret i64 %exitval
+}
+
 ;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
 ; CHECK-REMARKS: {{.*}}