Index: llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
+++ llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
@@ -312,13 +312,8 @@
 InductiveRangeCheck::parseRangeCheckICmp(Loop *L, ICmpInst *ICI,
                                          ScalarEvolution &SE, Value *&Index,
                                          Value *&Length, bool &IsSigned) {
-  auto IsNonNegativeAndNotLoopVarying = [&SE, L](Value *V) {
-    const SCEV *S = SE.getSCEV(V);
-    if (isa<SCEVCouldNotCompute>(S))
-      return false;
-
-    return SE.getLoopDisposition(S, L) == ScalarEvolution::LoopInvariant &&
-           SE.isKnownNonNegative(S);
+  auto IsLoopInvariant = [&SE, L](Value *V) {
+    return SE.isLoopInvariant(SE.getSCEV(V), L);
   };
 
   ICmpInst::Predicate Pred = ICI->getPredicate();
@@ -350,7 +345,7 @@
       return RANGE_CHECK_LOWER;
     }
 
-    if (IsNonNegativeAndNotLoopVarying(LHS)) {
+    if (IsLoopInvariant(LHS)) {
       Index = RHS;
       Length = LHS;
       return RANGE_CHECK_UPPER;
@@ -362,7 +357,7 @@
     LLVM_FALLTHROUGH;
   case ICmpInst::ICMP_UGT:
     IsSigned = false;
-    if (IsNonNegativeAndNotLoopVarying(LHS)) {
+    if (IsLoopInvariant(LHS)) {
       Index = RHS;
       Length = LHS;
       return RANGE_CHECK_BOTH;
Index: llvm/trunk/test/Transforms/IRCE/non_known_positive_end.ll
===================================================================
--- llvm/trunk/test/Transforms/IRCE/non_known_positive_end.ll
+++ llvm/trunk/test/Transforms/IRCE/non_known_positive_end.ll
@@ -0,0 +1,139 @@
+; RUN: opt -verify-loop-info -irce -irce-print-range-checks -irce-print-changed-loops %s -S 2>&1 | FileCheck %s
+; RUN: opt -verify-loop-info -passes='require<branch-prob>,loop(irce)' -irce-print-range-checks -irce-print-changed-loops %s -S 2>&1 | FileCheck %s
+
+; Make sure that we can pick up both range checks.
+define void @test_01(i32 *%arr, i32* %a_len_ptr, i32* %size_ptr) {
+
+; CHECK-LABEL: @test_01(
+
+entry:
+  %len = load i32, i32* %a_len_ptr, !range !0
+  %size = load i32, i32* %size_ptr
+  %first_iter_check = icmp sle i32 %size, 0
+  br i1 %first_iter_check, label %exit, label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
+  %rc1 = icmp slt i32 %iv, %len
+  %rc2 = icmp slt i32 %iv, %size
+  ; CHECK: %rc = and i1 true, true
+  %rc = and i1 %rc1, %rc2
+  br i1 %rc, label %backedge, label %out_of_bounds
+
+
+backedge:
+  %iv.next = add i32 %iv, 1
+  %arr_el_ptr = getelementptr i32, i32* %arr, i32 %iv
+  %el = load i32, i32* %arr_el_ptr
+  %loopcond = icmp ne i32 %iv, %size
+  br i1 %loopcond, label %loop, label %exit
+
+exit:
+  ret void
+
+out_of_bounds:
+  ret void
+}
+
+; Same as test_01, unsigned predicates.
+define void @test_02(i32 *%arr, i32* %a_len_ptr, i32* %size_ptr) {
+
+; CHECK-LABEL: @test_02(
+
+entry:
+  %len = load i32, i32* %a_len_ptr, !range !0
+  %size = load i32, i32* %size_ptr
+  %first_iter_check = icmp sle i32 %size, 0
+  br i1 %first_iter_check, label %exit, label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
+  %rc1 = icmp ult i32 %iv, %len
+  %rc2 = icmp ult i32 %iv, %size
+  ; CHECK: %rc = and i1 true, true
+  %rc = and i1 %rc1, %rc2
+  br i1 %rc, label %backedge, label %out_of_bounds
+
+
+backedge:
+  %iv.next = add i32 %iv, 1
+  %arr_el_ptr = getelementptr i32, i32* %arr, i32 %iv
+  %el = load i32, i32* %arr_el_ptr
+  %loopcond = icmp ne i32 %iv, %size
+  br i1 %loopcond, label %loop, label %exit
+
+exit:
+  ret void
+
+out_of_bounds:
+  ret void
+}
+
+define void @test_03(i32 *%arr, i32* %a_len_ptr, i32* %size_ptr) {
+
+; CHECK-LABEL: @test_03(
+
+entry:
+  %len = load i32, i32* %a_len_ptr, !range !0
+  %size = load i32, i32* %size_ptr
+  %first_iter_check = icmp eq i32 %size, 0
+  br i1 %first_iter_check, label %exit, label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
+  %rc1 = icmp slt i32 %iv, %len
+  %rc2 = icmp slt i32 %iv, %size
+  ; CHECK: %rc = and i1 true, true
+  %rc = and i1 %rc1, %rc2
+  br i1 %rc, label %backedge, label %out_of_bounds
+
+
+backedge:
+  %iv.next = add i32 %iv, 1
+  %arr_el_ptr = getelementptr i32, i32* %arr, i32 %iv
+  %el = load i32, i32* %arr_el_ptr
+  %loopcond = icmp ne i32 %iv, %len
+  br i1 %loopcond, label %loop, label %exit
+
+exit:
+  ret void
+
+out_of_bounds:
+  ret void
+}
+
+define void @test_04(i32 *%arr, i32* %a_len_ptr, i32* %size_ptr) {
+
+; CHECK-LABEL: @test_04(
+
+entry:
+  %len = load i32, i32* %a_len_ptr, !range !0
+  %size = load i32, i32* %size_ptr
+  %first_iter_check = icmp eq i32 %size, 0
+  br i1 %first_iter_check, label %exit, label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
+  %rc1 = icmp ult i32 %iv, %len
+  %rc2 = icmp ult i32 %iv, %size
+  ; CHECK: %rc = and i1 true, true
+  %rc = and i1 %rc1, %rc2
+  br i1 %rc, label %backedge, label %out_of_bounds
+
+
+backedge:
+  %iv.next = add i32 %iv, 1
+  %arr_el_ptr = getelementptr i32, i32* %arr, i32 %iv
+  %el = load i32, i32* %arr_el_ptr
+  %loopcond = icmp ne i32 %iv, %len
+  br i1 %loopcond, label %loop, label %exit
+
+exit:
+  ret void
+
+out_of_bounds:
+  ret void
+}
+
+!0 = !{i32 0, i32 2147483647}
+!1 = !{!"branch_weights", i32 64, i32 4}
Index: llvm/trunk/test/Transforms/IRCE/range_intersect_miscompile.ll
===================================================================
--- llvm/trunk/test/Transforms/IRCE/range_intersect_miscompile.ll
+++ llvm/trunk/test/Transforms/IRCE/range_intersect_miscompile.ll
@@ -168,20 +168,20 @@
   ret void
 }
 
-; We do not know whether %n is positive or negative, so we prohibit IRCE in
-; order to avoid incorrect intersection of signed and unsigned ranges.
-; The condition %tmp2 can be eliminated.
+; We can also properly eliminate range check against %n which is not always
+; known positive.
 
 define void @test_04(i32* %p) {
 
 ; CHECK-LABEL: test_04
+; CHECK:       entry
 ; CHECK-NOT:   preloop
-; CHECK-NOT:   postloop
 ; CHECK:         %tmp2 = icmp sgt i32 %iv.prev, -1
 ; CHECK-NEXT:    br i1 true, label %loop_header.split.us, label %exit
 ; CHECK:       range_check_block:
 ; CHECK-NEXT:    %range_check = icmp slt i32 %iv, %n
-; CHECK-NEXT:    br i1 %range_check, label %loop_latch, label %deopt
+; CHECK-NEXT:    br i1 true, label %loop_latch, label %deopt
+; CHECK:       postloop:
 
 entry:
   %n = load i32, i32* %p
@@ -226,7 +226,7 @@
 ; CHECK-LABEL: test_05
 ; CHECK-NOT:     preloop
 ; CHECK:         entry:
-; CHECK-NEXT:      %n = load i32, i32* %p, !range !6
+; CHECK-NEXT:      %n = load i32, i32* %p, !range !
 ; CHECK-NEXT:      [[CMP_1:%[^ ]+]] = icmp ugt i32 %n, 2
 ; CHECK-NEXT:      %exit.mainloop.at = select i1 [[CMP_1]], i32 %n, i32 2
 ; CHECK-NEXT:      [[CMP_2:%[^ ]+]] = icmp ult i32 2, %exit.mainloop.at