[llvm] [LV] Align debug location of the widen-phi to the original phi. (PR #120338)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Elvis Wang (ElvisWang123)

<details>
<summary>Changes</summary>

This patch align the debug location of the widen-phi to the debug location of original phi.

Split from: #<!-- -->120054 

---
Full diff: https://github.com/llvm/llvm-project/pull/120338.diff


4 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/VPlan.h (+4-3) 
- (modified) llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp (+1-1) 
- (modified) llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp (+1) 
- (modified) llvm/test/Transforms/LoopVectorize/dbg-outer-loop-vect.ll (+2-2) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 12208a7968338b..2f1f3f5745c8ae 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -2311,9 +2311,10 @@ class VPWidenPHIRecipe : public VPSingleDefRecipe {
   SmallVector<VPBasicBlock *, 2> IncomingBlocks;
 
 public:
-  /// Create a new VPWidenPHIRecipe for \p Phi with start value \p Start.
-  VPWidenPHIRecipe(PHINode *Phi, VPValue *Start = nullptr)
-      : VPSingleDefRecipe(VPDef::VPWidenPHISC, ArrayRef<VPValue *>(), Phi) {
+  /// Create a new VPWidenPHIRecipe for \p Phi with start value \p Start and
+  /// debug location \p DL.
+  VPWidenPHIRecipe(PHINode *Phi, VPValue *Start = nullptr, DebugLoc DL = {})
+      : VPSingleDefRecipe(VPDef::VPWidenPHISC, ArrayRef<VPValue *>(), Phi, DL) {
     if (Start)
       addOperand(Start);
   }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp b/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp
index 6e633739fcc3dd..140cea3c700d87 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanHCFGBuilder.cpp
@@ -308,7 +308,7 @@ void PlainCFGBuilder::createVPInstructionsForVPBB(VPBasicBlock *VPBB,
       // Phi node's operands may have not been visited at this point. We create
       // an empty VPInstruction that we will fix once the whole plain CFG has
       // been built.
-      NewVPV = new VPWidenPHIRecipe(Phi);
+      NewVPV = new VPWidenPHIRecipe(Phi, nullptr, Phi->getDebugLoc());
       VPBB->appendRecipe(cast<VPWidenPHIRecipe>(NewVPV));
       PhisToFix.push_back(Phi);
     } else {
diff --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index ab95b647f211b7..b695d1419ca4e7 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -3456,6 +3456,7 @@ void VPWidenPHIRecipe::execute(VPTransformState &State) {
   assert(EnableVPlanNativePath &&
          "Non-native vplans are not expected to have VPWidenPHIRecipes.");
 
+  State.setDebugLocFrom(getDebugLoc());
   Value *Op0 = State.get(getOperand(0));
   Type *VecTy = Op0->getType();
   Value *VecPhi = State.Builder.CreatePHI(VecTy, 2, "vec.phi");
diff --git a/llvm/test/Transforms/LoopVectorize/dbg-outer-loop-vect.ll b/llvm/test/Transforms/LoopVectorize/dbg-outer-loop-vect.ll
index 66aceab9fb27c8..44afa34100c299 100644
--- a/llvm/test/Transforms/LoopVectorize/dbg-outer-loop-vect.ll
+++ b/llvm/test/Transforms/LoopVectorize/dbg-outer-loop-vect.ll
@@ -15,8 +15,8 @@ define void @foo(ptr %h) !dbg !4 {
 ; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[FOR_COND_CLEANUP32:%.*]] ]
 ; CHECK-NEXT:    br label [[FOR_COND5_PREHEADER1:%.*]], !dbg [[DBG21]]
 ; CHECK:       for.cond5.preheader1:
-; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ zeroinitializer, [[VECTOR_BODY]] ], [ [[TMP4:%.*]], [[FOR_COND5_PREHEADER1]] ], !dbg [[DBG21]]
-; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr i32, ptr [[H]], <4 x i64> [[VEC_PHI]], !dbg [[DBG21]]
+; CHECK-NEXT:    [[VEC_PHI:%.*]] = phi <4 x i64> [ zeroinitializer, [[VECTOR_BODY]] ], [ [[TMP4:%.*]], [[FOR_COND5_PREHEADER1]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr i32, ptr [[H]], <4 x i64> [[VEC_PHI]]
 ; CHECK-NEXT:    call void @llvm.masked.scatter.v4i32.v4p0(<4 x i32> zeroinitializer, <4 x ptr> [[TMP0]], i32 4, <4 x i1> splat (i1 true)), !dbg [[DBG22:![0-9]+]]
 ; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr i32, <4 x ptr> [[TMP0]], i64 1, !dbg [[DBG22]]
 ; CHECK-NEXT:    call void @llvm.masked.scatter.v4i32.v4p0(<4 x i32> splat (i32 1), <4 x ptr> [[TMP1]], i32 4, <4 x i1> splat (i1 true)), !dbg [[DBG22]]

``````````

</details>


https://github.com/llvm/llvm-project/pull/120338