diff --git a/lib/Transforms/Scalar/GuardWidening.cpp b/lib/Transforms/Scalar/GuardWidening.cpp
index f407a32bf05..e6b2c472b28 100644
--- a/lib/Transforms/Scalar/GuardWidening.cpp
+++ b/lib/Transforms/Scalar/GuardWidening.cpp
@@ -551,26 +551,33 @@ bool GuardWideningImpl::combineRangeChecks(
     SmallVectorImpl<GuardWideningImpl::RangeCheck> &RangeChecksOut) {
   unsigned OldCount = Checks.size();
   while (!Checks.empty()) {
-    Value *Base = Checks[0].Base;
-    Value *Length = Checks[0].Length;
-    auto ChecksStart =
-        remove_if(Checks, [&](GuardWideningImpl::RangeCheck &RC) {
-          return RC.Base == Base && RC.Length == Length;
-        });
+    // Pick all of the range checks with a specific base and length, and try to
+    // merge them.
+    Value *CurrentBase = Checks.front().Base;
+    Value *CurrentLength = Checks.front().Length;
 
-    unsigned CheckCount = std::distance(ChecksStart, Checks.end());
-    assert(CheckCount != 0 && "We know we have at least one!");
+    SmallVector<GuardWideningImpl::RangeCheck, 3> CurrentChecks;
 
-    if (CheckCount < 3) {
-      RangeChecksOut.insert(RangeChecksOut.end(), ChecksStart, Checks.end());
-      Checks.erase(ChecksStart, Checks.end());
+    auto IsCurrentCheck = [&](GuardWideningImpl::RangeCheck &RC) {
+      return RC.Base == CurrentBase && RC.Length == CurrentLength;
+    };
+
+    std::copy_if(Checks.begin(), Checks.end(),
+                 std::back_inserter(CurrentChecks), IsCurrentCheck);
+    Checks.erase(remove_if(Checks, IsCurrentCheck), Checks.end());
+
+    assert(CurrentChecks.size() != 0 && "We know we have at least one!");
+
+    if (CurrentChecks.size() < 3) {
+      RangeChecksOut.insert(RangeChecksOut.end(), CurrentChecks.begin(),
+                            CurrentChecks.end());
       continue;
     }
 
-    // CheckCount will typically be 3 here, but so far there has been no need to
-    // hard-code that fact.
+    // CurrentChecks.size() will typically be 3 here, but so far there has been
+    // no need to hard-code that fact.
 
-    std::sort(ChecksStart, Checks.end(),
+    std::sort(CurrentChecks.begin(), CurrentChecks.end(),
               [&](const GuardWideningImpl::RangeCheck &LHS,
                   const GuardWideningImpl::RangeCheck &RHS) {
       return LHS.Offset->getValue().slt(RHS.Offset->getValue());
@@ -578,8 +585,8 @@ bool GuardWideningImpl::combineRangeChecks(
 
     // Note: std::sort should not invalidate the ChecksStart iterator.
 
-    ConstantInt *MinOffset = ChecksStart->Offset,
-                *MaxOffset = Checks.back().Offset;
+    ConstantInt *MinOffset = CurrentChecks.front().Offset,
+                *MaxOffset = CurrentChecks.back().Offset;
 
     unsigned BitWidth = MaxOffset->getValue().getBitWidth();
     if ((MaxOffset->getValue() - MinOffset->getValue())
@@ -593,7 +600,8 @@ bool GuardWideningImpl::combineRangeChecks(
     };
 
     if (MaxDiff.isMinValue() ||
-        !std::all_of(std::next(ChecksStart), Checks.end(), OffsetOK))
+        !std::all_of(std::next(CurrentChecks.begin()), CurrentChecks.end(),
+                     OffsetOK))
       return false;
 
     // We have a series of f+1 checks as:
@@ -631,12 +639,8 @@ bool GuardWideningImpl::combineRangeChecks(
     // For Chk_0 to succeed, we'd have to have k_f-k_0 (the range highlighted
     // with 'x' above) to be at least >u INT_MIN.
 
-    RangeChecksOut.emplace_back(Base, MinOffset, Length,
-                                ChecksStart->CheckInst);
-    RangeChecksOut.emplace_back(Base, MaxOffset, Length,
-                                Checks.back().CheckInst);
-
-    Checks.erase(ChecksStart, Checks.end());
+    RangeChecksOut.emplace_back(CurrentChecks.front());
+    RangeChecksOut.emplace_back(CurrentChecks.back());
   }
 
   assert(RangeChecksOut.size() <= OldCount && "We pessimized!");
diff --git a/test/Transforms/GuardWidening/range-check-merging.ll b/test/Transforms/GuardWidening/range-check-merging.ll
index 304eebc9b86..6440dadce1e 100644
--- a/test/Transforms/GuardWidening/range-check-merging.ll
+++ b/test/Transforms/GuardWidening/range-check-merging.ll
@@ -194,4 +194,42 @@ entry:
   ret void
 }
 
+
+define void @f_7(i32 %x, i32* %length_buf) {
+; CHECK-LABEL: @f_7(
+
+; CHECK:  [[COND_0:%[^ ]+]] = and i1 %chk3.b, %chk0.b
+; CHECK:  [[COND_1:%[^ ]+]] = and i1 %chk0.a, [[COND_0]]
+; CHECK:  [[COND_2:%[^ ]+]] = and i1 %chk3.a, [[COND_1]]
+; CHECK:  call void (i1, ...) @llvm.experimental.guard(i1 [[COND_2]]) [ "deopt"() ]
+
+entry:
+  %length_a = load volatile i32, i32* %length_buf, !range !0
+  %length_b = load volatile i32, i32* %length_buf, !range !0
+  %chk0.a = icmp ult i32 %x, %length_a
+  %chk0.b = icmp ult i32 %x, %length_b
+  %chk0 = and i1 %chk0.a, %chk0.b
+  call void(i1, ...) @llvm.experimental.guard(i1 %chk0) [ "deopt"() ]
+
+  %x.inc1 = add i32 %x, 1
+  %chk1.a = icmp ult i32 %x.inc1, %length_a
+  %chk1.b = icmp ult i32 %x.inc1, %length_b
+  %chk1 = and i1 %chk1.a, %chk1.b
+  call void(i1, ...) @llvm.experimental.guard(i1 %chk1) [ "deopt"() ]
+
+  %x.inc2 = add i32 %x, 2
+  %chk2.a = icmp ult i32 %x.inc2, %length_a
+  %chk2.b = icmp ult i32 %x.inc2, %length_b
+  %chk2 = and i1 %chk2.a, %chk2.b
+  call void(i1, ...) @llvm.experimental.guard(i1 %chk2) [ "deopt"() ]
+
+  %x.inc3 = add i32 %x, 3
+  %chk3.a = icmp ult i32 %x.inc3, %length_a
+  %chk3.b = icmp ult i32 %x.inc3, %length_b
+  %chk3 = and i1 %chk3.a, %chk3.b
+  call void(i1, ...) @llvm.experimental.guard(i1 %chk3) [ "deopt"() ]
+  ret void
+}
+
+
 !0 = !{i32 0, i32 2147483648}