[llvm] [VPlan] Delay adding canonical IV increment and exit branches. (PR #82270)

[via llvm-commits]

================
@@ -18,6 +18,19 @@ define void @simple_memset(i32 %val, ptr %ptr, i64 %n) #0 {
 ; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N_RND_UP]], [[N_MOD_VF]]
 ; CHECK-NEXT:    [[TMP61:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP62:%.*]] = mul i64 [[TMP61]], 16
+; CHECK-NEXT:    [[TMP25:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP26:%.*]] = mul i64 [[TMP25]], 4
+; CHECK-NEXT:    [[INDEX_PART_NEXT:%.*]] = add i64 0, [[TMP26]]
+; CHECK-NEXT:    [[TMP27:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP28:%.*]] = mul i64 [[TMP27]], 8
+; CHECK-NEXT:    [[INDEX_PART_NEXT1:%.*]] = add i64 0, [[TMP28]]
+; CHECK-NEXT:    [[TMP29:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP30:%.*]] = mul i64 [[TMP29]], 12
+; CHECK-NEXT:    [[INDEX_PART_NEXT2:%.*]] = add i64 0, [[TMP30]]
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1.i64(i64 0, i64 [[UMAX]])
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_ENTRY3:%.*]] = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1.i64(i64 [[INDEX_PART_NEXT]], i64 [[UMAX]])
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_ENTRY4:%.*]] = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1.i64(i64 [[INDEX_PART_NEXT1]], i64 [[UMAX]])
+; CHECK-NEXT:    [[ACTIVE_LANE_MASK_ENTRY5:%.*]] = call <vscale x 4 x i1> @llvm.get.active.lane.mask.nxv4i1.i64(i64 [[INDEX_PART_NEXT2]], i64 [[UMAX]])
----------------
ayalz wrote:

Is this addition intentional?

https://github.com/llvm/llvm-project/pull/82270