[llvm] [VectorCombine] Drop invariant.group from scalarized stores (PR #212473)

[via llvm-commits]

https://github.com/ParkHanbum created https://github.com/llvm/llvm-project/pull/212473

!invariant.group is tied to a pointer SSA value, so it cannot be copied
from a vector store to a scalar store that uses a newly created GEP.
Drop the metadata after copying the remaining store metadata and update
the regression expectations.

Fixes https://github.com/llvm/llvm-project/issues/212472

>From bd0d4ac9e7d3c407e8f4538bfd083c2d1fbfe98b Mon Sep 17 00:00:00 2001
From: hanbeom <kese111 at gmail.com>
Date: Tue, 28 Jul 2026 19:31:36 +0900
Subject: [PATCH 1/2] Add scalarized-store invariant.group coverage

---
 .../VectorCombine/load-insert-store.ll         | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/llvm/test/Transforms/VectorCombine/load-insert-store.ll b/llvm/test/Transforms/VectorCombine/load-insert-store.ll
index 897b113c197cf..563880d8c73a5 100644
--- a/llvm/test/Transforms/VectorCombine/load-insert-store.ll
+++ b/llvm/test/Transforms/VectorCombine/load-insert-store.ll
@@ -30,6 +30,20 @@ entry:
   ret void
 }
 
+; Record the current propagation of !invariant.group from the vector store to
+; the scalar store, even though the latter uses a new GEP.
+define void @insert_store_invariant_group(ptr %p, i16 %x) {
+; CHECK-LABEL: @insert_store_invariant_group(
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds <8 x i16>, ptr [[P:%.*]], i32 0, i32 1
+; CHECK-NEXT:    store i16 [[X:%.*]], ptr [[GEP]], align 2, !invariant.group [[META0:![0-9]+]]
+; CHECK-NEXT:    ret void
+;
+  %v = load <8 x i16>, ptr %p, align 2
+  %v1 = insertelement <8 x i16> %v, i16 %x, i32 1
+  store <8 x i16> %v1, ptr %p, align 2, !invariant.group !0
+  ret void
+}
+
 ; To verify case when index is out of bounds
 define void @insert_store_outofbounds(ptr %q, i16 zeroext %s) {
 ; CHECK-LABEL: @insert_store_outofbounds(
@@ -847,3 +861,7 @@ bb:
 
 declare i32 @bar(i32, i1) readonly
 declare double @llvm.log2.f64(double)
+
+; CHECK: [[META0]] = !{}
+
+!0 = !{}

>From b3775a2cc4a005a9f9deb6948d2045987780d5c8 Mon Sep 17 00:00:00 2001
From: hanbeom <kese111 at gmail.com>
Date: Tue, 28 Jul 2026 19:32:49 +0900
Subject: [PATCH 2/2] [VectorCombine] Drop invariant.group from scalarized
 stores

!invariant.group is tied to a pointer SSA value, so it cannot be copied
from a vector store to a scalar store that uses a newly created GEP.
Drop the metadata after copying the remaining store metadata and update
the regression expectations.

Fixes #212472
---
 llvm/lib/Transforms/Vectorize/VectorCombine.cpp         | 3 +++
 llvm/test/Transforms/VectorCombine/load-insert-store.ll | 8 +++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
index 726f564b1aad9..38bebefa3bc79 100644
--- a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
+++ b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
@@ -2009,6 +2009,9 @@ bool VectorCombine::foldSingleElementStore(Instruction &I) {
         {ConstantInt::get(Idx->getType(), 0), Idx});
     StoreInst *NSI = Builder.CreateStore(NewElement, GEP);
     NSI->copyMetadata(*SI);
+    // !invariant.group is tied to the pointer SSA value and cannot be
+    // transferred from the vector store to a scalar store through a new GEP.
+    NSI->setMetadata(LLVMContext::MD_invariant_group, nullptr);
     Align ScalarOpAlignment = computeAlignmentAfterScalarization(
         std::max(SI->getAlign(), Load->getAlign()), NewElement->getType(), Idx,
         *DL);
diff --git a/llvm/test/Transforms/VectorCombine/load-insert-store.ll b/llvm/test/Transforms/VectorCombine/load-insert-store.ll
index 563880d8c73a5..fd5e78db5fa9a 100644
--- a/llvm/test/Transforms/VectorCombine/load-insert-store.ll
+++ b/llvm/test/Transforms/VectorCombine/load-insert-store.ll
@@ -30,12 +30,12 @@ entry:
   ret void
 }
 
-; Record the current propagation of !invariant.group from the vector store to
-; the scalar store, even though the latter uses a new GEP.
+; !invariant.group is tied to the pointer SSA value. The scalar store uses a
+; new GEP and must not inherit the metadata from the vector store.
 define void @insert_store_invariant_group(ptr %p, i16 %x) {
 ; CHECK-LABEL: @insert_store_invariant_group(
 ; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds <8 x i16>, ptr [[P:%.*]], i32 0, i32 1
-; CHECK-NEXT:    store i16 [[X:%.*]], ptr [[GEP]], align 2, !invariant.group [[META0:![0-9]+]]
+; CHECK-NEXT:    store i16 [[X:%.*]], ptr [[GEP]], align 2
 ; CHECK-NEXT:    ret void
 ;
   %v = load <8 x i16>, ptr %p, align 2
@@ -862,6 +862,4 @@ bb:
 declare i32 @bar(i32, i1) readonly
 declare double @llvm.log2.f64(double)
 
-; CHECK: [[META0]] = !{}
-
 !0 = !{}