[llvm] 7293720 - [VPlan] Create vector header and latch VPBBs in createInitialVPlan (NFC)

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2024-07-09T12:41:12+01:00
New Revision: 72937203dd3beb294b52d5e61d1523acf046456f

URL: https://github.com/llvm/llvm-project/commit/72937203dd3beb294b52d5e61d1523acf046456f
DIFF: https://github.com/llvm/llvm-project/commit/72937203dd3beb294b52d5e61d1523acf046456f.diff

LOG: [VPlan] Create vector header and latch VPBBs in createInitialVPlan (NFC)

The empty header and latch blocks can be created together with the
vector loop region.

This is in preparation for splitting up the very large
tryToBuildVPlanWithVPRecipes into several distinct functions, as
suggested multiple times, including in
https://github.com/llvm/llvm-project/pull/94760

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/lib/Transforms/Vectorize/VPlan.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 0ca460733858c..631f89b1225cb 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8548,11 +8548,6 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
       createTripCountSCEV(Legal->getWidestInductionType(), PSE, OrigLoop),
       *PSE.getSE(), RequiresScalarEpilogueCheck, CM.foldTailByMasking(),
       OrigLoop);
-  VPBasicBlock *HeaderVPBB = new VPBasicBlock("vector.body");
-  VPBasicBlock *LatchVPBB = new VPBasicBlock("vector.latch");
-  VPBlockUtils::insertBlockAfter(LatchVPBB, HeaderVPBB);
-  Plan->getVectorLoopRegion()->setEntry(HeaderVPBB);
-  Plan->getVectorLoopRegion()->setExiting(LatchVPBB);
 
   // Don't use getDecisionAndClampRange here, because we don't know the UF
   // so this function is better to be conservative, rather than to split
@@ -8606,6 +8601,7 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
   LoopBlocksDFS DFS(OrigLoop);
   DFS.perform(LI);
 
+  VPBasicBlock *HeaderVPBB = Plan->getVectorLoopRegion()->getEntryBasicBlock();
   VPBasicBlock *VPBB = HeaderVPBB;
   BasicBlock *HeaderBB = OrigLoop->getHeader();
   bool NeedsMasks =

diff  --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
index 20b72b1609ca4..1018a5e8c5707 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -820,8 +820,14 @@ VPlanPtr VPlan::createInitialVPlan(const SCEV *TripCount, ScalarEvolution &SE,
   auto Plan = std::make_unique<VPlan>(Entry, VecPreheader);
   Plan->TripCount =
       vputils::getOrCreateVPValueForSCEVExpr(*Plan, TripCount, SE);
-  // Create empty VPRegionBlock, to be filled during processing later.
-  auto *TopRegion = new VPRegionBlock("vector loop", false /*isReplicator*/);
+  // Create VPRegionBlock, with empty header and latch blocks, to be filled
+  // during processing later.
+  VPBasicBlock *HeaderVPBB = new VPBasicBlock("vector.body");
+  VPBasicBlock *LatchVPBB = new VPBasicBlock("vector.latch");
+  VPBlockUtils::insertBlockAfter(LatchVPBB, HeaderVPBB);
+  auto *TopRegion = new VPRegionBlock(HeaderVPBB, LatchVPBB, "vector loop",
+                                      false /*isReplicator*/);
+
   VPBlockUtils::insertBlockAfter(TopRegion, VecPreheader);
   VPBasicBlock *MiddleVPBB = new VPBasicBlock("middle.block");
   VPBlockUtils::insertBlockAfter(MiddleVPBB, TopRegion);