diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -148,6 +148,7 @@
   Instruction *SliceUpIllegalIntegerPHI(PHINode &PN);
   Instruction *visitPHINode(PHINode &PN);
   Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
+  Value *splitConstantGEP(Value *Src);
   Instruction *visitGEPOfGEP(GetElementPtrInst &GEP, GEPOperator *Src);
   Instruction *visitGEPOfBitcast(BitCastInst *BCI, GetElementPtrInst &GEP);
   Instruction *visitAllocaInst(AllocaInst &AI);
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1935,6 +1935,28 @@
   return SelectInst::Create(Cond, NewTrueC, NewFalseC, "", nullptr, Sel);
 }
 
+// For a chain of GEP in the form GEP (GEP ... (GEP (GEP p C1) X1) ... Xn) C2
+// where C1 and C2 are constants, and GEP X1 ... Xn each has no other uses,
+// we can split GEP p C1 from the use-def chain so that it can be reassociated
+// and merged with the outermost GEP by visitGEPofGEP.
+Value *InstCombinerImpl::splitConstantGEP(Value *Src) {
+  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) {
+    APInt Offset(DL.getIndexTypeSizeInBits(GEP->getType()), 0);
+    if (GEP->hasAllConstantIndices() &&
+        GEP->accumulateConstantOffset(DL, Offset))
+      return Builder.CreateGEP(GEP->getSourceElementType(),
+                               GEP->getPointerOperand(),
+                               SmallVector<Value *>(GEP->indices()),
+                               GEP->getName(), GEP->isInBounds());
+    if (Src->hasOneUse())
+      if (Value *NewV = splitConstantGEP(GEP->getPointerOperand()))
+        return Builder.CreateGEP(GEP->getSourceElementType(), NewV,
+                                 SmallVector<Value *>(GEP->indices()),
+                                 GEP->getName(), GEP->isInBounds());
+  }
+  return nullptr;
+}
+
 Instruction *InstCombinerImpl::visitGEPOfGEP(GetElementPtrInst &GEP,
                                              GEPOperator *Src) {
   // Combine Indices - If the source pointer to this getelementptr instruction
@@ -2444,6 +2466,19 @@
     if (Instruction *I = visitGEPOfGEP(GEP, Src))
       return I;
 
+  // This check must be after visitGEPOfGEP, since GEP (GEP p C1) C2 can be
+  // merged by it. If GEP has zero offset, do not transform because it is a zero
+  // cost bitcast.
+  APInt Offset(DL.getIndexTypeSizeInBits(GEP.getType()), 0);
+  if (GEP.hasAllConstantIndices() && !GEP.hasAllZeroIndices() &&
+      GEP.accumulateConstantOffset(DL, Offset) && !Offset.isZero())
+    if (Value *V = splitConstantGEP(GEP.getPointerOperand())) {
+      GetElementPtrInst *NewGEP = GetElementPtrInst::Create(
+          GEP.getSourceElementType(), V, SmallVector<Value *>(GEP.indices()));
+      NewGEP->setIsInBounds(GEP.isInBounds());
+      return NewGEP;
+    }
+
   // Skip if GEP source element type is scalable. The type alloc size is unknown
   // at compile-time.
   if (GEP.getNumIndices() == 1 && !IsGEPSrcEleScalable) {
diff --git a/llvm/test/Transforms/InstCombine/gep-merge-constant-indices.ll b/llvm/test/Transforms/InstCombine/gep-merge-constant-indices.ll
--- a/llvm/test/Transforms/InstCombine/gep-merge-constant-indices.ll
+++ b/llvm/test/Transforms/InstCombine/gep-merge-constant-indices.ll
@@ -9,6 +9,8 @@
 %struct.B = type { i8, [3 x i16], %struct.A, float }
 %struct.C = type { i8, i32, i32 }
 
+declare void @use(ptr %p)
+
 ; result = (i32*) p + 3
 define ptr @mergeBasic(ptr %p) {
 ; CHECK-LABEL: @mergeBasic(
@@ -220,3 +222,76 @@
   %2 = getelementptr inbounds i32, ptr %1, i64 1
   ret ptr %2
 }
+
+; If the first and last in a chain of GEP are constant indexed, they can be
+; merged, even if the first GEP has multiple uses.
+; result = (i8*) ((i32*) p + a + b) + 22
+define ptr @gepChain1(ptr %p, i64 %a, i64 %b) {
+; CHECK-LABEL: @gepChain1(
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i64, ptr [[P:%.*]], i64 2
+; CHECK-NEXT:    call void @use(ptr nonnull [[TMP1]])
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr i32, ptr [[P]], i64 [[A:%.*]]
+; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr i32, ptr [[TMP2]], i64 [[B:%.*]]
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i8, ptr [[TMP3]], i64 22
+; CHECK-NEXT:    ret ptr [[TMP4]]
+;
+  %1 = getelementptr inbounds i64, ptr %p, i64 2
+  call void @use(ptr %1)
+  %2 = getelementptr inbounds i32, ptr %1, i64 %a
+  %3 = getelementptr inbounds i32, ptr %2, i64 %b
+  %4 = getelementptr inbounds i16, ptr %3, i64 3
+  ret ptr %4
+}
+
+; Constant indexed GEP cancel out.
+; result = (i32*) p + a + b
+define ptr @gepChain2(ptr %p, i64 %a, i64 %b) {
+; CHECK-LABEL: @gepChain2(
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i64, ptr [[P:%.*]], i64 2
+; CHECK-NEXT:    call void @use(ptr nonnull [[TMP1]])
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr i32, ptr [[P]], i64 [[A:%.*]]
+; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr i32, ptr [[TMP2]], i64 [[B:%.*]]
+; CHECK-NEXT:    ret ptr [[TMP3]]
+;
+  %1 = getelementptr inbounds i64, ptr %p, i64 2
+  call void @use(ptr %1)
+  %2 = getelementptr inbounds i32, ptr %1, i64 %a
+  %3 = getelementptr inbounds i32, ptr %2, i64 %b
+  %4 = getelementptr inbounds i16, ptr %3, i64 -8
+  ret ptr %4
+}
+
+; Negative test. If the last GEP offset is zero, do not merge since it is a
+; bitcast with no cost.
+define ptr @gepChainZeroOffset(ptr %p, i64 %a) {
+; CHECK-LABEL: @gepChainZeroOffset(
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i64, ptr [[P:%.*]], i64 2
+; CHECK-NEXT:    call void @use(ptr nonnull [[TMP1]])
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i64 [[A:%.*]]
+; CHECK-NEXT:    ret ptr [[TMP2]]
+;
+  %1 = getelementptr inbounds i64, ptr %p, i64 2
+  call void @use(ptr %1)
+  %2 = getelementptr inbounds i32, ptr %1, i64 %a
+  %3 = getelementptr inbounds [4 x i16], ptr %2, i64 1, i64 -4
+  ret ptr %3
+}
+
+; Negative test. Do not merge if a GEP in the middle has multiple use, such that
+; the transform is invalid.
+define ptr @gepChainMultipleUse(ptr %p, i64 %a) {
+; CHECK-LABEL: @gepChainMultipleUse(
+; CHECK-NEXT:    [[TMP1:%.*]] = getelementptr inbounds i64, ptr [[P:%.*]], i64 2
+; CHECK-NEXT:    call void @use(ptr nonnull [[TMP1]])
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds i32, ptr [[TMP1]], i64 [[A:%.*]]
+; CHECK-NEXT:    call void @use(ptr nonnull [[TMP2]])
+; CHECK-NEXT:    [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[TMP2]], i64 3
+; CHECK-NEXT:    ret ptr [[TMP3]]
+;
+  %1 = getelementptr inbounds i64, ptr %p, i64 2
+  call void @use(ptr %1)
+  %2 = getelementptr inbounds i32, ptr %1, i64 %a
+  call void @use(ptr %2)
+  %3 = getelementptr inbounds i32, ptr %2, i64 3
+  ret ptr %3
+}