diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h b/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
index 5d03b66b0ce33..ebca2d855a467 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
@@ -175,7 +175,10 @@ class VPBuilder {
 
   VPValue *createOr(VPValue *LHS, VPValue *RHS, DebugLoc DL = {},
                     const Twine &Name = "") {
-    return createInstruction(Instruction::BinaryOps::Or, {LHS, RHS}, DL, Name);
+
+    return tryInsertInstruction(new VPInstruction(
+        Instruction::BinaryOps::Or, {LHS, RHS},
+        VPRecipeWithIRFlags::DisjointFlagsTy(false), DL, Name));
   }
 
   VPValue *createSelect(VPValue *Cond, VPValue *TrueVal, VPValue *FalseVal,
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 3baca43f72767..707a826ecdc25 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -913,6 +913,11 @@ class VPRecipeWithIRFlags : public VPSingleDefRecipe {
     WrapFlagsTy(bool HasNUW, bool HasNSW) : HasNUW(HasNUW), HasNSW(HasNSW) {}
   };
 
+  struct DisjointFlagsTy {
+    char IsDisjoint : 1;
+    DisjointFlagsTy(bool IsDisjoint) : IsDisjoint(IsDisjoint) {}
+  };
+
 protected:
   struct GEPFlagsTy {
     char IsInBounds : 1;
@@ -920,9 +925,6 @@ class VPRecipeWithIRFlags : public VPSingleDefRecipe {
   };
 
 private:
-  struct DisjointFlagsTy {
-    char IsDisjoint : 1;
-  };
   struct ExactFlagsTy {
     char IsExact : 1;
   };
@@ -1016,6 +1018,12 @@ class VPRecipeWithIRFlags : public VPSingleDefRecipe {
       : VPSingleDefRecipe(SC, Operands, DL), OpType(OperationType::FPMathOp),
         FMFs(FMFs) {}
 
+  template <typename IterT>
+  VPRecipeWithIRFlags(const unsigned char SC, IterT Operands,
+                      DisjointFlagsTy DisjointFlags, DebugLoc DL = {})
+      : VPSingleDefRecipe(SC, Operands, DL), OpType(OperationType::DisjointOp),
+        DisjointFlags(DisjointFlags) {}
+
 protected:
   template <typename IterT>
   VPRecipeWithIRFlags(const unsigned char SC, IterT Operands,
@@ -1221,6 +1229,14 @@ class VPInstruction : public VPRecipeWithIRFlags {
       : VPRecipeWithIRFlags(VPDef::VPInstructionSC, Operands, WrapFlags, DL),
         Opcode(Opcode), Name(Name.str()) {}
 
+  VPInstruction(unsigned Opcode, std::initializer_list<VPValue *> Operands,
+                DisjointFlagsTy DisjointFlag, DebugLoc DL = {},
+                const Twine &Name = "")
+      : VPRecipeWithIRFlags(VPDef::VPInstructionSC, Operands, DisjointFlag, DL),
+        Opcode(Opcode), Name(Name.str()) {
+    assert(Opcode == Instruction::Or && "only OR opcodes can be disjoint");
+  }
+
   VPInstruction(unsigned Opcode, std::initializer_list<VPValue *> Operands,
                 FastMathFlags FMFs, DebugLoc DL = {}, const Twine &Name = "");
 
diff --git a/llvm/test/Transforms/LoopVectorize/pr87378-vpinstruction-or-drop-poison-generating-flags.ll b/llvm/test/Transforms/LoopVectorize/pr87378-vpinstruction-or-drop-poison-generating-flags.ll
new file mode 100644
index 0000000000000..4e38630209b2d
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/pr87378-vpinstruction-or-drop-poison-generating-flags.ll
@@ -0,0 +1,132 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -p loop-vectorize -mattr="+v" -S %s | FileCheck %s
+
+target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128"
+target triple = "riscv64-unknown-linux-gnu"
+
+; Test case for https://github.com/llvm/llvm-project/issues/87378.
+define void @pr87378_vpinstruction_or_drop_poison_generating_flags(ptr %arg, i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: define void @pr87378_vpinstruction_or_drop_poison_generating_flags(
+; CHECK-SAME: ptr [[ARG:%.*]], i64 [[A:%.*]], i64 [[B:%.*]], i64 [[C:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP1:%.*]] = mul i64 [[TMP0]], 8
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1001, [[TMP1]]
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP3:%.*]] = mul i64 [[TMP2]], 8
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1001, [[TMP3]]
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 1001, [[N_MOD_VF]]
+; CHECK-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP5:%.*]] = mul i64 [[TMP4]], 8
+; CHECK-NEXT:    [[TMP6:%.*]] = call <vscale x 8 x i64> @llvm.experimental.stepvector.nxv8i64()
+; CHECK-NEXT:    [[TMP7:%.*]] = add <vscale x 8 x i64> [[TMP6]], zeroinitializer
+; CHECK-NEXT:    [[TMP8:%.*]] = mul <vscale x 8 x i64> [[TMP7]], shufflevector (<vscale x 8 x i64> insertelement (<vscale x 8 x i64> poison, i64 1, i64 0), <vscale x 8 x i64> poison, <vscale x 8 x i32> zeroinitializer)
+; CHECK-NEXT:    [[INDUCTION:%.*]] = add <vscale x 8 x i64> zeroinitializer, [[TMP8]]
+; CHECK-NEXT:    [[TMP9:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP10:%.*]] = mul i64 [[TMP9]], 8
+; CHECK-NEXT:    [[TMP11:%.*]] = mul i64 1, [[TMP10]]
+; CHECK-NEXT:    [[DOTSPLATINSERT:%.*]] = insertelement <vscale x 8 x i64> poison, i64 [[TMP11]], i64 0
+; CHECK-NEXT:    [[DOTSPLAT:%.*]] = shufflevector <vscale x 8 x i64> [[DOTSPLATINSERT]], <vscale x 8 x i64> poison, <vscale x 8 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 8 x i64> poison, i64 [[A]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 8 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 8 x i64> poison, <vscale x 8 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 8 x i64> poison, i64 [[B]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT2:%.*]] = shufflevector <vscale x 8 x i64> [[BROADCAST_SPLATINSERT1]], <vscale x 8 x i64> poison, <vscale x 8 x i32> zeroinitializer
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <vscale x 8 x i64> poison, i64 [[C]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT4:%.*]] = shufflevector <vscale x 8 x i64> [[BROADCAST_SPLATINSERT3]], <vscale x 8 x i64> poison, <vscale x 8 x i32> zeroinitializer
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <vscale x 8 x i64> [ [[INDUCTION]], [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP12:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT5:%.*]] = insertelement <vscale x 8 x i64> poison, i64 [[TMP12]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT6:%.*]] = shufflevector <vscale x 8 x i64> [[BROADCAST_SPLATINSERT5]], <vscale x 8 x i64> poison, <vscale x 8 x i32> zeroinitializer
+; CHECK-NEXT:    [[TMP13:%.*]] = icmp ule <vscale x 8 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[TMP14:%.*]] = icmp ule <vscale x 8 x i64> [[VEC_IND]], [[BROADCAST_SPLAT2]]
+; CHECK-NEXT:    [[TMP15:%.*]] = select <vscale x 8 x i1> [[TMP13]], <vscale x 8 x i1> [[TMP14]], <vscale x 8 x i1> zeroinitializer
+; CHECK-NEXT:    [[TMP16:%.*]] = xor <vscale x 8 x i1> [[TMP13]], shufflevector (<vscale x 8 x i1> insertelement (<vscale x 8 x i1> poison, i1 true, i64 0), <vscale x 8 x i1> poison, <vscale x 8 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP17:%.*]] = or <vscale x 8 x i1> [[TMP15]], [[TMP16]]
+; CHECK-NEXT:    [[TMP18:%.*]] = icmp ule <vscale x 8 x i64> [[VEC_IND]], [[BROADCAST_SPLAT4]]
+; CHECK-NEXT:    [[TMP19:%.*]] = select <vscale x 8 x i1> [[TMP17]], <vscale x 8 x i1> [[TMP18]], <vscale x 8 x i1> zeroinitializer
+; CHECK-NEXT:    [[TMP20:%.*]] = xor <vscale x 8 x i1> [[TMP14]], shufflevector (<vscale x 8 x i1> insertelement (<vscale x 8 x i1> poison, i1 true, i64 0), <vscale x 8 x i1> poison, <vscale x 8 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP21:%.*]] = select <vscale x 8 x i1> [[TMP13]], <vscale x 8 x i1> [[TMP20]], <vscale x 8 x i1> zeroinitializer
+; CHECK-NEXT:    [[TMP22:%.*]] = or <vscale x 8 x i1> [[TMP19]], [[TMP21]]
+; CHECK-NEXT:    [[PREDPHI:%.*]] = select <vscale x 8 x i1> [[TMP19]], <vscale x 8 x i64> [[BROADCAST_SPLAT6]], <vscale x 8 x i64> shufflevector (<vscale x 8 x i64> insertelement (<vscale x 8 x i64> poison, i64 poison, i64 0), <vscale x 8 x i64> poison, <vscale x 8 x i32> zeroinitializer)
+; CHECK-NEXT:    [[TMP23:%.*]] = extractelement <vscale x 8 x i64> [[PREDPHI]], i32 0
+; CHECK-NEXT:    [[TMP24:%.*]] = getelementptr i16, ptr [[ARG]], i64 [[TMP23]]
+; CHECK-NEXT:    [[TMP25:%.*]] = getelementptr i16, ptr [[TMP24]], i32 0
+; CHECK-NEXT:    call void @llvm.masked.store.nxv8i16.p0(<vscale x 8 x i16> zeroinitializer, ptr [[TMP25]], i32 2, <vscale x 8 x i1> [[TMP22]])
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 8 x i64> [[VEC_IND]], [[DOTSPLAT]]
+; CHECK-NEXT:    [[TMP26:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP26]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1001, [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br label [[LOOP_HEADER:%.*]]
+; CHECK:       loop.header:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; CHECK-NEXT:    [[C_1:%.*]] = icmp ule i64 [[IV]], [[A]]
+; CHECK-NEXT:    br i1 [[C_1]], label [[THEN_1:%.*]], label [[ELSE_1:%.*]]
+; CHECK:       then.1:
+; CHECK-NEXT:    [[C_2:%.*]] = icmp ule i64 [[IV]], [[B]]
+; CHECK-NEXT:    br i1 [[C_2]], label [[ELSE_1]], label [[MERGE:%.*]]
+; CHECK:       else.1:
+; CHECK-NEXT:    [[C_3:%.*]] = icmp ule i64 [[IV]], [[C]]
+; CHECK-NEXT:    br i1 [[C_3]], label [[THEN_2:%.*]], label [[LOOP_LATCH]]
+; CHECK:       then.2:
+; CHECK-NEXT:    br label [[MERGE]]
+; CHECK:       merge:
+; CHECK-NEXT:    [[IDX:%.*]] = phi i64 [ poison, [[THEN_1]] ], [ [[IV]], [[THEN_2]] ]
+; CHECK-NEXT:    [[GETELEMENTPTR:%.*]] = getelementptr i16, ptr [[ARG]], i64 [[IDX]]
+; CHECK-NEXT:    store i16 0, ptr [[GETELEMENTPTR]], align 2
+; CHECK-NEXT:    br label [[LOOP_LATCH]]
+; CHECK:       loop.latch:
+; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; CHECK-NEXT:    [[ICMP:%.*]] = icmp eq i64 [[IV]], 1000
+; CHECK-NEXT:    br i1 [[ICMP]], label [[EXIT]], label [[LOOP_HEADER]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %c.1 = icmp ule i64 %iv, %a
+  br i1 %c.1, label %then.1, label %else.1
+
+then.1:
+  %c.2 = icmp ule i64 %iv, %b
+  br i1 %c.2, label %else.1, label %merge
+
+else.1:
+  %c.3 = icmp ule i64 %iv, %c
+  br i1 %c.3, label %then.2, label %loop.latch
+
+then.2:
+  br label %merge
+
+merge:
+  %idx = phi i64 [ poison, %then.1 ], [ %iv, %then.2 ]
+  %getelementptr = getelementptr i16, ptr %arg, i64 %idx
+  store i16 0, ptr %getelementptr, align 2
+  br label %loop.latch
+
+loop.latch:
+  %iv.next = add i64 %iv, 1
+  %icmp = icmp eq i64 %iv, 1000
+  br i1 %icmp, label %exit, label %loop.header
+
+exit:
+  ret void
+}
+;.
+; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
+; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
+; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META2]], [[META1]]}
+;.