[llvm] [LV] Prefer fixed VFs for epilogue vectorization (PR #211814)

[David Sherwood via llvm-commits]

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@@ -38,22 +38,22 @@ define void @cost_store_i8(ptr %dst) #0 {
 ; DEFAULT-NEXT:    [[CMP_N:%.*]] = icmp eq i64 101, [[N_VEC]]
 ; DEFAULT-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[VEC_EPILOG_ITER_CHECK:%.*]]
 ; DEFAULT:       vec.epilog.iter.check:
-; DEFAULT-NEXT:    [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i64 [[N_MOD_VF]], [[TMP15]]
+; DEFAULT-NEXT:    [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i64 [[N_MOD_VF]], [[TMP12]]
 ; DEFAULT-NEXT:    br i1 [[MIN_EPILOG_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH]], label [[VEC_EPILOG_PH]], !prof [[PROF3:![0-9]+]]
 ; DEFAULT:       vec.epilog.ph:
 ; DEFAULT-NEXT:    [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
-; DEFAULT-NEXT:    [[TMP11:%.*]] = call i64 @llvm.vscale.i64()
-; DEFAULT-NEXT:    [[TMP12:%.*]] = shl nuw i64 [[TMP11]], 2
-; DEFAULT-NEXT:    [[N_MOD_VF2:%.*]] = urem i64 101, [[TMP12]]
+; DEFAULT-NEXT:    [[TMP14:%.*]] = call i64 @llvm.vscale.i64()
+; DEFAULT-NEXT:    [[TMP11:%.*]] = shl nuw i64 [[TMP14]], 2
+; DEFAULT-NEXT:    [[N_MOD_VF2:%.*]] = urem i64 101, [[TMP11]]
 ; DEFAULT-NEXT:    [[N_VEC3:%.*]] = sub i64 101, [[N_MOD_VF2]]
 ; DEFAULT-NEXT:    br label [[VEC_EPILOG_VECTOR_BODY:%.*]]
 ; DEFAULT:       vec.epilog.vector.body:
 ; DEFAULT-NEXT:    [[INDEX1:%.*]] = phi i64 [ [[VEC_EPILOG_RESUME_VAL]], [[VEC_EPILOG_PH]] ], [ [[INDEX_NEXT2:%.*]], [[VEC_EPILOG_VECTOR_BODY]] ]
 ; DEFAULT-NEXT:    [[TMP9:%.*]] = getelementptr i8, ptr [[DST]], i64 [[INDEX1]]
 ; DEFAULT-NEXT:    store <vscale x 4 x i8> zeroinitializer, ptr [[TMP9]], align 1
-; DEFAULT-NEXT:    [[INDEX_NEXT2]] = add nuw i64 [[INDEX1]], [[TMP12]]
-; DEFAULT-NEXT:    [[TMP14:%.*]] = icmp eq i64 [[INDEX_NEXT2]], [[N_VEC3]]
-; DEFAULT-NEXT:    br i1 [[TMP14]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; DEFAULT-NEXT:    [[INDEX_NEXT2]] = add nuw i64 [[INDEX1]], [[TMP11]]
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david-arm wrote:

Changes in this file can be reverted.

https://github.com/llvm/llvm-project/pull/211814