[llvm] [VPlan] Add initial CFG simplification, removing BranchOnCond true. (PR #106748)

[via llvm-commits]

================
@@ -42,10 +41,10 @@ define void @clamped_tc_8(ptr nocapture %dst, i32 %n, i64 %val) vscale_range(1,1
 ; CHECK-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <vscale x 8 x i1> @llvm.get.active.lane.mask.nxv8i1.i64(i64 [[INDEX_NEXT]], i64 8)
 ; CHECK-NEXT:    br i1 true, label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
----------------
ayalz wrote:

This branch-on-true from vector.body to middle.block or back to itself, can/should also be eliminated - as part of optimizing a vector loop found to have a trip-count of 1?

https://github.com/llvm/llvm-project/pull/106748