Index: lib/Transforms/InstCombine/InstructionCombining.cpp
===================================================================
--- lib/Transforms/InstCombine/InstructionCombining.cpp
+++ lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1544,6 +1544,28 @@
     if (!shouldMergeGEPs(*cast<GEPOperator>(&GEP), *Src))
       return nullptr;
 
+    SmallVector<Value *, 8> Indices;
+
+    auto createGEPWithIndices = [&]() {
+      return GEP.isInBounds() && Src->isInBounds()
+                 ? GetElementPtrInst::CreateInBounds(
+                       Src->getSourceElementType(), Src->getOperand(0), Indices,
+                       GEP.getName())
+                 : GetElementPtrInst::Create(Src->getSourceElementType(),
+                                             Src->getOperand(0), Indices,
+                                             GEP.getName());
+    };
+
+    // Fold Src into GEP if the first index of GEP is zero. We perform this
+    // simplification regardless of whether Src is also in a GEP chain.
+    if (isa<Constant>(*GEP.idx_begin()) &&
+        cast<Constant>(*GEP.idx_begin())->isNullValue() &&
+        Src->getNumOperands() != 1) {
+      Indices.append(Src->op_begin() + 1, Src->op_end());
+      Indices.append(GEP.idx_begin() + 1, GEP.idx_end());
+      return createGEPWithIndices();
+    }
+
     // Note that if our source is a gep chain itself then we wait for that
     // chain to be resolved before we perform this transformation.  This
     // avoids us creating a TON of code in some cases.
@@ -1552,8 +1574,6 @@
       if (SrcGEP->getNumOperands() == 2 && shouldMergeGEPs(*Src, *SrcGEP))
         return nullptr;   // Wait until our source is folded to completion.
 
-    SmallVector<Value*, 8> Indices;
-
     // Find out whether the last index in the source GEP is a sequential idx.
     bool EndsWithSequential = false;
     for (gep_type_iterator I = gep_type_begin(*Src), E = gep_type_end(*Src);
@@ -1590,22 +1610,8 @@
       Indices.append(Src->op_begin()+1, Src->op_end()-1);
       Indices.push_back(Sum);
       Indices.append(GEP.op_begin()+2, GEP.op_end());
-    } else if (isa<Constant>(*GEP.idx_begin()) &&
-               cast<Constant>(*GEP.idx_begin())->isNullValue() &&
-               Src->getNumOperands() != 1) {
-      // Otherwise we can do the fold if the first index of the GEP is a zero
-      Indices.append(Src->op_begin()+1, Src->op_end());
-      Indices.append(GEP.idx_begin()+1, GEP.idx_end());
+      return createGEPWithIndices();
     }
-
-    if (!Indices.empty())
-      return GEP.isInBounds() && Src->isInBounds()
-                 ? GetElementPtrInst::CreateInBounds(
-                       Src->getSourceElementType(), Src->getOperand(0), Indices,
-                       GEP.getName())
-                 : GetElementPtrInst::Create(Src->getSourceElementType(),
-                                             Src->getOperand(0), Indices,
-                                             GEP.getName());
   }
 
   if (GEP.getNumIndices() == 1) {
Index: test/Transforms/InstCombine/getelementptr.ll
===================================================================
--- test/Transforms/InstCombine/getelementptr.ll
+++ test/Transforms/InstCombine/getelementptr.ll
@@ -931,4 +931,16 @@
   ret i32 addrspace(1)* %x
 }
 
+define i32* @resolve_gep_chains(%pair* %p, i64 %i) {
+; CHECK-LABEL: @resolve_gep_chains(
+; CHECK-NEXT:    [[TMP0:%.*]] = getelementptr %pair, %pair* %p, i64 %i
+; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr %pair, %pair* [[TMP0]], i64 1, i32 1
+; CHECK-NEXT:    ret i32* [[TMP2]]
+;
+  %tmp0 = getelementptr %pair, %pair* %p, i64 %i
+  %tmp1 = getelementptr %pair, %pair* %tmp0, i64 1
+  %tmp2 = getelementptr %pair, %pair* %tmp1, i64 0, i32 1
+  ret i32* %tmp2
+}
+
 ; CHECK: attributes [[NUW]] = { nounwind }