[llvm] [VPlan] Simplify branch on False in VPlan transform (NFC). (PR #140409)

[via llvm-commits]

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@@ -1841,43 +1841,39 @@ void VPlanTransforms::truncateToMinimalBitwidths(
   }
 }
 
-/// Remove BranchOnCond recipes with true conditions together with removing
-/// dead edges to their successors.
-static void removeBranchOnCondTrue(VPlan &Plan) {
+/// Remove BranchOnCond recipes with true or false conditions together with
+/// removing dead edges to their successors.
+static void removeBranchOnConst(VPlan &Plan) {
   using namespace llvm::VPlanPatternMatch;
   for (VPBasicBlock *VPBB : VPBlockUtils::blocksOnly<VPBasicBlock>(
            vp_depth_first_shallow(Plan.getEntry()))) {
+    VPValue *Cond;
     if (VPBB->getNumSuccessors() != 2 || VPBB == Plan.getEntry() ||
-        !match(&VPBB->back(), m_BranchOnCond(m_True())))
+        !match(&VPBB->back(), m_BranchOnCond(m_VPValue(Cond))))
       continue;
 
-    VPBasicBlock *RemovedSucc = cast<VPBasicBlock>(VPBB->getSuccessors()[1]);
+    unsigned RemovedIdx;
+    if (match(Cond, m_True()))
+      RemovedIdx = 1;
+    else if (match(Cond, m_False()))
+      RemovedIdx = 0;
+    else
+      continue;
+
+    VPBasicBlock *RemovedSucc =
+        cast<VPBasicBlock>(VPBB->getSuccessors()[RemovedIdx]);
     const auto &Preds = RemovedSucc->getPredecessors();
     assert(count(Preds, VPBB) == 1 &&
            "There must be a single edge between VPBB and its successor");
-    unsigned DeadIdx = std::distance(Preds.begin(), find(Preds, VPBB));
-
-    // Values coming from VPBB into ResumePhi recipes of RemoveSucc are removed
-    // from these recipes.
+    // Values coming from VPBB into phi recipes of RemoveSucc are removed from
+    // these recipes.
     for (VPRecipeBase &R : make_early_inc_range(*RemovedSucc)) {
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ayalz wrote:

Operands are removed in place keeping recipes intact rather than replacing the recipes - is `make_early_inc_range` still needed?

https://github.com/llvm/llvm-project/pull/140409