[VPlan] Use VPlan predecessors in VPWidenPHIRecipe (NFC). #126388

fhahn · 2025-02-08T21:13:35Z

Update VPWidenPHIRecipe to use the predecessors in VPlan to determine the incoming blocks instead of tracking them separately. This brings VPWidenPHIrecipe in line with the other phi recipes.

llvmbot · 2025-02-08T21:14:09Z

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-vectorizers

Author: Florian Hahn (fhahn)

Changes

Update VPWidenPHIRecipe to use the predecessors in VPlan to determine the incoming blocks instead of tracking them separately. This brings VPWidenPHIrecipe in line with the other phi recipes.

Full diff: https://github.com/llvm/llvm-project/pull/126388.diff

6 Files Affected:

(modified) llvm/lib/Transforms/Vectorize/VPlan.h (+6-18)
(modified) llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp (+12-9)
(modified) llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp (+15)
(modified) llvm/lib/Transforms/Vectorize/VPlanUtils.h (+1-9)
(modified) llvm/test/Transforms/LoopVectorize/outer-loop-wide-phis.ll (+1-1)
(modified) llvm/unittests/Transforms/Vectorize/VPlanTest.cpp (+2-2)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 3816e1b61576a3d..f2f118f5d2980c1 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1958,13 +1958,12 @@ class VPScalarPHIRecipe : public VPHeaderPHIRecipe {
 #endif
 };
 
-/// A recipe for handling phis that are widened in the vector loop.
-/// In the VPlan native path, all incoming VPValues & VPBasicBlock pairs are
-/// managed in the recipe directly.
+/// A recipe for widened phis. Incoming values are operands of the recipe and
+/// their operand index corresponds to the incoming predeocessor block. If the
+/// recipe is placed in an entry block to a (non-replicate) region, it must have
+/// exactly 2 incoming values, from from the predecessors of the region and one
+/// from the exiting block of the region.
 class VPWidenPHIRecipe : public VPSingleDefRecipe {
-  /// List of incoming blocks. Only used in the VPlan native path.
-  SmallVector<VPBasicBlock *, 2> IncomingBlocks;
-
 public:
   /// Create a new VPWidenPHIRecipe for \p Phi with start value \p Start and
   /// debug location \p DL.
@@ -1991,19 +1990,8 @@ class VPWidenPHIRecipe : public VPSingleDefRecipe {
              VPSlotTracker &SlotTracker) const override;
 #endif
 
-  /// Adds a pair (\p IncomingV, \p IncomingBlock) to the phi.
-  void addIncoming(VPValue *IncomingV, VPBasicBlock *IncomingBlock) {
-    addOperand(IncomingV);
-    IncomingBlocks.push_back(IncomingBlock);
-  }
-
   /// Returns the \p I th incoming VPBasicBlock.
-  VPBasicBlock *getIncomingBlock(unsigned I) { return IncomingBlocks[I]; }
-
-  /// Set the \p I th incoming VPBasicBlock to \p IncomingBlock.
-  void setIncomingBlock(unsigned I, VPBasicBlock *IncomingBlock) {
-    IncomingBlocks[I] = IncomingBlock;
-  }
+  VPBasicBlock *getIncomingBlock(unsigned I);
 
   /// Returns the \p I th incoming VPValue.
   VPValue *getIncomingValue(unsigned I) { return getOperand(I); }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp b/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp
index 5a2e5d7cfee48d0..c94ea35e8112e25 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp
@@ -136,19 +136,22 @@ void PlainCFGBuilder::fixPhiNodes() {
       // predecessor is the first operand of the recipe.
       assert(Phi->getNumOperands() == 2);
       BasicBlock *LoopPred = L->getLoopPredecessor();
-      VPPhi->addIncoming(
-          getOrCreateVPOperand(Phi->getIncomingValueForBlock(LoopPred)),
-          BB2VPBB[LoopPred]);
+      VPPhi->addOperand(
+          getOrCreateVPOperand(Phi->getIncomingValueForBlock(LoopPred)));
       BasicBlock *LoopLatch = L->getLoopLatch();
-      VPPhi->addIncoming(
-          getOrCreateVPOperand(Phi->getIncomingValueForBlock(LoopLatch)),
-          BB2VPBB[LoopLatch]);
+      VPPhi->addOperand(
+          getOrCreateVPOperand(Phi->getIncomingValueForBlock(LoopLatch)));
       continue;
     }
 
-    for (unsigned I = 0; I != Phi->getNumOperands(); ++I)
-      VPPhi->addIncoming(getOrCreateVPOperand(Phi->getIncomingValue(I)),
-                         BB2VPBB[Phi->getIncomingBlock(I)]);
+    // Add operands for VPPhi in the order matching its predecessors in VPlan.
+    DenseMap<const VPBasicBlock *, VPValue *> IncomingValues;
+    for (unsigned I = 0; I != Phi->getNumOperands(); ++I) {
+      IncomingValues[BB2VPBB[Phi->getIncomingBlock(I)]] =
+          getOrCreateVPOperand(Phi->getIncomingValue(I));
+    }
+    for (VPBlockBase *Pred : VPPhi->getParent()->getPredecessors())
+      VPPhi->addOperand(IncomingValues.lookup(Pred->getExitingBasicBlock()));
   }
 }
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index bc80c5ea0b1b2af..b86b6285fc50183 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -3577,6 +3577,21 @@ void VPReductionPHIRecipe::print(raw_ostream &O, const Twine &Indent,
 }
 #endif
 
+VPBasicBlock *VPWidenPHIRecipe::getIncomingBlock(unsigned I) {
+  VPBasicBlock *Parent = getParent();
+  VPBlockBase *Pred = nullptr;
+  if (Parent->getNumPredecessors() == 0) {
+    auto *R = Parent->getParent();
+    assert(R && R->getEntry() == Parent);
+    assert(I < 2);
+    Pred = I == 0 ? R->getSinglePredecessor() : R;
+  } else {
+    Pred = Parent->getPredecessors()[I];
+  }
+
+  return Pred->getExitingBasicBlock();
+}
+
 void VPWidenPHIRecipe::execute(VPTransformState &State) {
   assert(EnableVPlanNativePath &&
          "Non-native vplans are not expected to have VPWidenPHIRecipes.");
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUtils.h b/llvm/lib/Transforms/Vectorize/VPlanUtils.h
index ac5e1978fcfbe00..6ddb88308955f1a 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUtils.h
+++ b/llvm/lib/Transforms/Vectorize/VPlanUtils.h
@@ -169,16 +169,8 @@ class VPBlockUtils {
   static void reassociateBlocks(VPBlockBase *Old, VPBlockBase *New) {
     for (auto *Pred : to_vector(Old->getPredecessors()))
       Pred->replaceSuccessor(Old, New);
-    for (auto *Succ : to_vector(Old->getSuccessors())) {
+    for (auto *Succ : to_vector(Old->getSuccessors()))
       Succ->replacePredecessor(Old, New);
-
-      // Replace any references to Old in widened phi incoming blocks.
-      for (auto &R : Succ->getEntryBasicBlock()->phis())
-        if (auto *WidenPhiR = dyn_cast<VPWidenPHIRecipe>(&R))
-          for (unsigned I = 0; I < WidenPhiR->getNumOperands(); I++)
-            if (WidenPhiR->getIncomingBlock(I) == Old)
-              WidenPhiR->setIncomingBlock(I, cast<VPBasicBlock>(New));
-    }
     New->setPredecessors(Old->getPredecessors());
     New->setSuccessors(Old->getSuccessors());
     Old->clearPredecessors();
diff --git a/llvm/test/Transforms/LoopVectorize/outer-loop-wide-phis.ll b/llvm/test/Transforms/LoopVectorize/outer-loop-wide-phis.ll
index 3f81c0f5c822a2e..c5d2f6acf85b380 100644
--- a/llvm/test/Transforms/LoopVectorize/outer-loop-wide-phis.ll
+++ b/llvm/test/Transforms/LoopVectorize/outer-loop-wide-phis.ll
@@ -134,7 +134,7 @@ define void @wide_phi_2_predecessors_phi_ops_swapped(ptr noalias %A, ptr noalias
 ; CHECK-NEXT:    [[WIDE_MASKED_GATHER:%.*]] = call <4 x i64> @llvm.masked.gather.v4i64.v4p0(<4 x ptr> [[TMP1]], i32 8, <4 x i1> splat (i1 true), <4 x i64> poison)
 ; CHECK-NEXT:    br label %[[INNER_LATCH4]]
 ; CHECK:       [[INNER_LATCH4]]:
-; CHECK-NEXT:    [[VEC_PHI5:%.*]] = phi <4 x i64> [ zeroinitializer, %[[INNER_HEADER1]] ], [ [[WIDE_MASKED_GATHER]], %[[THEN3]] ]
+; CHECK-NEXT:    [[VEC_PHI5:%.*]] = phi <4 x i64> [ [[WIDE_MASKED_GATHER]], %[[THEN3]] ], [ zeroinitializer, %[[INNER_HEADER1]] ]
 ; CHECK-NEXT:    [[TMP2:%.*]] = add nsw <4 x i64> [[VEC_PHI5]], [[VEC_IND]]
 ; CHECK-NEXT:    [[TMP3]] = add nsw <4 x i64> [[TMP2]], [[VEC_PHI2]]
 ; CHECK-NEXT:    [[TMP4]] = add nuw nsw <4 x i64> [[VEC_PHI]], splat (i64 1)
diff --git a/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp b/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp
index 2f37c08bd9f117d..b17725382e33c56 100644
--- a/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp
+++ b/llvm/unittests/Transforms/Vectorize/VPlanTest.cpp
@@ -672,7 +672,7 @@ TEST_F(VPBasicBlockTest, reassociateBlocks) {
     auto *WidenPhi = new VPWidenPHIRecipe(nullptr);
     IntegerType *Int32 = IntegerType::get(C, 32);
     VPValue *Val = Plan.getOrAddLiveIn(ConstantInt::get(Int32, 1));
-    WidenPhi->addIncoming(Val, VPBB1);
+    WidenPhi->addOperand(Val);
     VPBB2->appendRecipe(WidenPhi);
 
     VPBasicBlock *VPBBNew = Plan.createVPBasicBlock("VPBBNew");
@@ -693,7 +693,7 @@ TEST_F(VPBasicBlockTest, reassociateBlocks) {
     auto *WidenPhi = new VPWidenPHIRecipe(nullptr);
     IntegerType *Int32 = IntegerType::get(C, 32);
     VPValue *Val = Plan.getOrAddLiveIn(ConstantInt::get(Int32, 1));
-    WidenPhi->addIncoming(Val, VPBB1);
+    WidenPhi->addOperand(Val);
     VPBB2->appendRecipe(WidenPhi);
 
     VPBasicBlock *VPBBNew = Plan.createVPBasicBlock("VPBBNew");

fhahn · 2025-02-08T21:15:14Z

#125481 made me think if tracking the incoming blocks separately is actually needed and it appears we can use the same approach as all other phi recipes I think

lukel97

LGTM, makes sense to me!

ayalz

Some post-approval comments and thoughts.

ayalz · 2025-02-09T06:53:12Z

llvm/lib/Transforms/Vectorize/VPlan.h

+/// exactly 2 incoming values, from from the predecessors of the region and one
+/// from the exiting block of the region.


Suggested change

/// exactly 2 incoming values, from from the predecessors of the region and one

/// from the exiting block of the region.

/// exactly 2 incoming values, the first from the predecessors of the region and the second

/// from the exiting block of the region.

Done thanks!

ayalz · 2025-02-09T07:06:27Z

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

+  VPBasicBlock *Parent = getParent();
+  VPBlockBase *Pred = nullptr;
+  if (Parent->getNumPredecessors() == 0) {
+    auto *R = Parent->getParent();


nit:

Suggested change

auto *R = Parent->getParent();

auto *Region = Parent->getParent();

R is often used for Recipe.

Done thanks

ayalz · 2025-02-09T07:11:45Z

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

+    assert(R && R->getEntry() == Parent);
+    assert(I < 2);


Error messages.
VPlans holding VPWidenPHIRecipes have only loop regions, which have a single predecessor - the preheader, even when nested?
Worth asserting R is not a replicating region.

Added error messages and updated assert thanks.

VPlans holding VPWidenPHIRecipes have only loop regions, which have a single predecessor - the preheader, even when nested?

Yes at the moment (getSinglePredecessor will assert that)

ayalz · 2025-02-09T07:18:41Z

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

+    auto *R = Parent->getParent();
+    assert(R && R->getEntry() == Parent);
+    assert(I < 2);
+    Pred = I == 0 ? R->getSinglePredecessor() : R;


If I == 1 then the enclosing region is returned, whose exiting block feeds the VPWidenPHIRecipe across the backedge? Worth a comment.

Added a comment, thanks!

ayalz · 2025-02-09T09:19:29Z

llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp

@@ -136,19 +136,22 @@ void PlainCFGBuilder::fixPhiNodes() {
      // predecessor is the first operand of the recipe.
      assert(Phi->getNumOperands() == 2);


(independent) Error message.

Done in 620a515

ayalz · 2025-02-09T09:21:04Z

llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp

-          getOrCreateVPOperand(Phi->getIncomingValueForBlock(LoopPred)),
-          BB2VPBB[LoopPred]);
+      VPPhi->addOperand(
+          getOrCreateVPOperand(Phi->getIncomingValueForBlock(LoopPred)));


(independent) This first operand can be set when creating the VPWidenPHIRecipe, only the second operand requires backpatching.

ayalz · 2025-02-09T09:22:10Z

llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp

-    for (unsigned I = 0; I != Phi->getNumOperands(); ++I)
-      VPPhi->addIncoming(getOrCreateVPOperand(Phi->getIncomingValue(I)),
-                         BB2VPBB[Phi->getIncomingBlock(I)]);
+    // Add operands for VPPhi in the order matching its predecessors in VPlan.


(independent) The operands of non-header VPWidenPHIRecipes can be set when creating it, rather than here.

Done in 30f44c9

ayalz · 2025-02-09T09:53:01Z

llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp

-      VPPhi->addIncoming(getOrCreateVPOperand(Phi->getIncomingValue(I)),
-                         BB2VPBB[Phi->getIncomingBlock(I)]);
+    // Add operands for VPPhi in the order matching its predecessors in VPlan.
+    DenseMap<const VPBasicBlock *, VPValue *> IncomingValues;


Suggested change

DenseMap<const VPBasicBlock *, VPValue *> IncomingValues;

DenseMap<const VPBasicBlock *, VPValue *> VPPredToIncomingValue;

Done thanks!

ayalz · 2025-02-09T09:58:05Z

llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp

+          getOrCreateVPOperand(Phi->getIncomingValue(I));
+    }
+    for (VPBlockBase *Pred : VPPhi->getParent()->getPredecessors())
+      VPPhi->addOperand(IncomingValues.lookup(Pred->getExitingBasicBlock()));


Note: if/when the reverse mapping VPBB2BB is available, this could be done by

VPPhi->addOperand(Phi->getIncomingValueForBlock(VPBB2BB[Pred->getExitingBasicBlock()]));

ayalz · 2025-02-09T10:07:21Z

llvm/lib/Transforms/Vectorize/VPlan.h

-  void setIncomingBlock(unsigned I, VPBasicBlock *IncomingBlock) {
-    IncomingBlocks[I] = IncomingBlock;
-  }
+  VPBasicBlock *getIncomingBlock(unsigned I);


Follow-up: make VPWidenPHIRecipe a VPInstruction by inlining both getIncomingValue() and getIncomingBlock() (in VPlan the latter fits a VPBB rather than a phi recipe) into their only user - fixNonInductionPHIs().

I am not sure if VPInstruction is the best place, as it may be beneficial to have an easier/more direct way to check if the node is phi-like. But it can probably share most of the logic with VPScalarPhiRecipe eventually.

Making VPWidenPHIRecipe be a VPInstruction would simplify "buildLoop" VPlan produced by HCFGBuilder, making it more consistent ("Widen"? All recipes are scalar at this point) and aligned with "wrapInput" VPlan/Region/Blocks which consist of VPIRInstructions - for phi's and non-phi's alike (with the option of introducing other recipes between them).

fhahn

Thanks, I'll take care of the independent suggestions separately.

fhahn · 2025-02-12T20:07:12Z

llvm/lib/Transforms/Vectorize/VPlan.h

+/// exactly 2 incoming values, from from the predecessors of the region and one
+/// from the exiting block of the region.


Done thanks!

fhahn · 2025-02-12T20:08:47Z

llvm/lib/Transforms/Vectorize/VPlan.h

-  void setIncomingBlock(unsigned I, VPBasicBlock *IncomingBlock) {
-    IncomingBlocks[I] = IncomingBlock;
-  }
+  VPBasicBlock *getIncomingBlock(unsigned I);


I am not sure if VPInstruction is the best place, as it may be beneficial to have an easier/more direct way to check if the node is phi-like. But it can probably share most of the logic with VPScalarPhiRecipe eventually.

fhahn · 2025-02-12T20:10:16Z

llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp

-      VPPhi->addIncoming(getOrCreateVPOperand(Phi->getIncomingValue(I)),
-                         BB2VPBB[Phi->getIncomingBlock(I)]);
+    // Add operands for VPPhi in the order matching its predecessors in VPlan.
+    DenseMap<const VPBasicBlock *, VPValue *> IncomingValues;


Done thanks!

fhahn · 2025-02-12T20:12:21Z

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

+  VPBasicBlock *Parent = getParent();
+  VPBlockBase *Pred = nullptr;
+  if (Parent->getNumPredecessors() == 0) {
+    auto *R = Parent->getParent();


Done thanks

fhahn · 2025-02-12T20:14:05Z

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

+    assert(R && R->getEntry() == Parent);
+    assert(I < 2);


Added error messages and updated assert thanks.

VPlans holding VPWidenPHIRecipes have only loop regions, which have a single predecessor - the preheader, even when nested?

Yes at the moment (getSinglePredecessor will assert that)

fhahn · 2025-02-12T20:15:18Z

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

+    auto *R = Parent->getParent();
+    assert(R && R->getEntry() == Parent);
+    assert(I < 2);
+    Pred = I == 0 ? R->getSinglePredecessor() : R;


Added a comment, thanks!

ayalz

Last minor nits, LGTM too.

ayalz · 2025-02-12T21:47:52Z

llvm/lib/Transforms/Vectorize/VPlan.h

-/// In the VPlan native path, all incoming VPValues & VPBasicBlock pairs are
-/// managed in the recipe directly.
+/// A recipe for widened phis. Incoming values are operands of the recipe and
+/// their operand index corresponds to the incoming predeocessor block. If the


Suggested change

/// their operand index corresponds to the incoming predeocessor block. If the

/// their operand index corresponds to the incoming predecessor block. If the

Done thanks

ayalz · 2025-02-12T21:48:13Z

llvm/lib/Transforms/Vectorize/VPlan.h

+/// A recipe for widened phis. Incoming values are operands of the recipe and
+/// their operand index corresponds to the incoming predeocessor block. If the
+/// recipe is placed in an entry block to a (non-replicate) region, it must have
+/// exactly 2 incoming values, the first from the predecessors of the region and


Suggested change

/// exactly 2 incoming values, the first from the predecessors of the region and

/// exactly 2 incoming values, the first from the predecessor of the region and

Done thanks

ayalz · 2025-02-12T21:54:20Z

llvm/lib/Transforms/Vectorize/VPlan.h

-  void setIncomingBlock(unsigned I, VPBasicBlock *IncomingBlock) {
-    IncomingBlocks[I] = IncomingBlock;
-  }
+  VPBasicBlock *getIncomingBlock(unsigned I);


Making VPWidenPHIRecipe be a VPInstruction would simplify "buildLoop" VPlan produced by HCFGBuilder, making it more consistent ("Widen"? All recipes are scalar at this point) and aligned with "wrapInput" VPlan/Region/Blocks which consist of VPIRInstructions - for phi's and non-phi's alike (with the option of introducing other recipes between them).

ayalz · 2025-02-12T21:59:45Z

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

+  if (Parent->getNumPredecessors() == 0) {
+    auto *Region = Parent->getParent();
+    assert(Region && !Region->isReplicator() && Region->getEntry() == Parent &&
+           "must be in the entry block of a non-replicate region");
+    assert(
+        I < 2 && getNumOperands() == 2 &&
+        "when placed in an entry block, only 2 incoming blocks are available");
+
+    // I ==  0 selects the predecessor of the region, I == 1 selects the region
+    // itself whose exiting block feeds the phi across the backedge.
+    Pred = I == 0 ? Region->getSinglePredecessor() : Region;
+  } else {
+    Pred = Parent->getPredecessors()[I];
+  }


nit: better start with the 1-liner case first

Suggested change

if (Parent->getNumPredecessors() == 0) {

auto *Region = Parent->getParent();

assert(Region && !Region->isReplicator() && Region->getEntry() == Parent &&

"must be in the entry block of a non-replicate region");

assert(

I < 2 && getNumOperands() == 2 &&

"when placed in an entry block, only 2 incoming blocks are available");

// I == 0 selects the predecessor of the region, I == 1 selects the region

// itself whose exiting block feeds the phi across the backedge.

Pred = I == 0 ? Region->getSinglePredecessor() : Region;

} else {

Pred = Parent->getPredecessors()[I];

}

if (Parent->getNumPredecessors() > 0) {

Pred = Parent->getPredecessors()[I];

} else {

auto *Region = Parent->getParent();

assert(Region && !Region->isReplicator() && Region->getEntry() == Parent &&

"must be in the entry block of a non-replicate region");

assert(

I < 2 && getNumOperands() == 2 &&

"when placed in an entry block, only 2 incoming blocks are available");

// I == 0 selects the predecessor of the region, I == 1 selects the region

// itself whose exiting block feeds the phi across the backedge.

Pred = I == 0 ? Region->getSinglePredecessor() : Region;

}

Done thanks

Update VPWidenPHIRecipe to use the predecessors in VPlan to determine the incoming blocks instead of tracking them separately. This brings VPWidenPHIrecipe in line with the other phi recipes.

…(#126388) Update VPWidenPHIRecipe to use the predecessors in VPlan to determine the incoming blocks instead of tracking them separately. This brings VPWidenPHIRecipe in line with the other phi recipes. PR: llvm/llvm-project#126388

Suggested in #126388.

Suggested in llvm/llvm-project#126388.

Update HCFG builder to set the incoming values directly at construction for non-header phis. Simplification/clarification as suggested independently in #126388.

Update HCFG builder to set the incoming values directly at construction for non-header phis. Simplification/clarification as suggested independently in llvm/llvm-project#126388.

Update HCFG builder to set the incoming values directly at construction for non-header phis. Simplification/clarification as suggested independently in llvm#126388.

Update VPWidenPHIRecipe to use the predecessors in VPlan to determine the incoming blocks instead of tracking them separately. This brings VPWidenPHIRecipe in line with the other phi recipes. PR: llvm#126388

Suggested in llvm#126388.

Update HCFG builder to set the incoming values directly at construction for non-header phis. Simplification/clarification as suggested independently in llvm#126388.

Update VPWidenPHIRecipe to use the predecessors in VPlan to determine the incoming blocks instead of tracking them separately. This brings VPWidenPHIRecipe in line with the other phi recipes. PR: llvm#126388

Suggested in llvm#126388.

Update HCFG builder to set the incoming values directly at construction for non-header phis. Simplification/clarification as suggested independently in llvm#126388.

fhahn requested review from lukel97, ayalz and aniragil February 8, 2025 21:13

llvmbot added vectorizers llvm:transforms labels Feb 8, 2025

lukel97 approved these changes Feb 9, 2025

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ayalz reviewed Feb 9, 2025

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fhahn force-pushed the vpwiden-phi-remove-incoming-blocks branch from 6047df3 to ecf91bc Compare February 12, 2025 20:16

fhahn commented Feb 12, 2025

View reviewed changes

ayalz reviewed Feb 12, 2025

View reviewed changes

fhahn added 4 commits February 13, 2025 13:08

[VPlan] Use VPlan predecessors in VPWidenPHIRecipe (NFC).

ebc7ac6

Update VPWidenPHIRecipe to use the predecessors in VPlan to determine the incoming blocks instead of tracking them separately. This brings VPWidenPHIrecipe in line with the other phi recipes.

!fixup address latest comments, thanks!

29a43e8

!fixup address latest comments, thanks!

e5c2270

!fixup address latest comments, thanks

25b218c

fhahn force-pushed the vpwiden-phi-remove-incoming-blocks branch from ecf91bc to 25b218c Compare February 13, 2025 12:30

Merge branch 'main' into vpwiden-phi-remove-incoming-blocks

4195c8b

fhahn merged commit 6c62783 into llvm:main Feb 17, 2025
8 checks passed

fhahn deleted the vpwiden-phi-remove-incoming-blocks branch February 17, 2025 15:40

fhahn added a commit that referenced this pull request Feb 17, 2025

[VPlan] Add message to assert in HCFGBuilder (NFC).

620a515

Suggested in #126388.

github-actions bot pushed a commit to arm/arm-toolchain that referenced this pull request Feb 17, 2025

Automerge: [VPlan] Add message to assert in HCFGBuilder (NFC).

e842f63

Suggested in llvm/llvm-project#126388.

lukel97 mentioned this pull request Feb 18, 2025

[VPlan] Expand VPWidenIntOrFpInductionRecipe into separate recipes #118638

Open

YutongZhuu pushed a commit to YutongZhuu/llvm-project that referenced this pull request Mar 8, 2025

[VPlan] Add message to assert in HCFGBuilder (NFC).

e1c4e93

Suggested in llvm#126388.

YutongZhuu pushed a commit to YutongZhuu/llvm-project that referenced this pull request Mar 8, 2025

[VPlan] Add message to assert in HCFGBuilder (NFC).

3e13c55

Suggested in llvm#126388.

		/// exactly 2 incoming values, from from the predecessors of the region and one
		/// from the exiting block of the region.

	auto *R = Parent->getParent();
	auto *Region = Parent->getParent();

		@@ -136,19 +136,22 @@ void PlainCFGBuilder::fixPhiNodes() {
		// predecessor is the first operand of the recipe.
		assert(Phi->getNumOperands() == 2);

	DenseMap<const VPBasicBlock , VPValue > IncomingValues;
	DenseMap<const VPBasicBlock , VPValue > VPPredToIncomingValue;

	/// their operand index corresponds to the incoming predeocessor block. If the
	/// their operand index corresponds to the incoming predecessor block. If the

	/// exactly 2 incoming values, the first from the predecessors of the region and
	/// exactly 2 incoming values, the first from the predecessor of the region and

[VPlan] Use VPlan predecessors in VPWidenPHIRecipe (NFC). #126388

[VPlan] Use VPlan predecessors in VPWidenPHIRecipe (NFC). #126388

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fhahn commented Feb 8, 2025

llvmbot commented Feb 8, 2025 • edited Loading

fhahn commented Feb 8, 2025

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llvmbot commented Feb 8, 2025 •

edited

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