Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -2794,11 +2794,13 @@
       }(LHS);
       Opts.NullIsUnknownSize = F ? NullPointerIsDefined(F) : true;
       if (getObjectSize(LHS, LHSSize, DL, TLI, Opts) &&
-          getObjectSize(RHS, RHSSize, DL, TLI, Opts) &&
-          !LHSOffset.isNegative() && !RHSOffset.isNegative() &&
-          LHSOffset.ult(LHSSize) && RHSOffset.ult(RHSSize)) {
-        return ConstantInt::get(getCompareTy(LHS),
-                                !CmpInst::isTrueWhenEqual(Pred));
+          getObjectSize(RHS, RHSSize, DL, TLI, Opts)) {
+        APInt dist;
+        dist = LHSOffset - RHSOffset;
+        dist = dist.abs();
+        if (dist.ult(LHSSize) && dist.ult(RHSSize))
+          return ConstantInt::get(getCompareTy(LHS),
+                                  !CmpInst::isTrueWhenEqual(Pred));
       }
     }
 
Index: llvm/test/Transforms/InstSimplify/cmp-alloca-offsets.ll
===================================================================
--- llvm/test/Transforms/InstSimplify/cmp-alloca-offsets.ll
+++ llvm/test/Transforms/InstSimplify/cmp-alloca-offsets.ll
@@ -40,15 +40,9 @@
   ret i1 %res
 }
 
-; FIXME: Can't be equal
 define i1 @positive_non_equal_end() {
 ; CHECK-LABEL: @positive_non_equal_end(
-; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, ptr [[A]], i64 4
-; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, ptr [[B]], i64 4
-; CHECK-NEXT:    [[RES:%.*]] = icmp ne ptr [[A_OFF]], [[B_OFF]]
-; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK-NEXT:    ret i1 true
 ;
   %a = alloca i8, i32 4
   %b = alloca i8, i32 4
@@ -142,15 +136,9 @@
   ret i1 %res
 }
 
-; FIXME: Can't be equal
 define i1 @mixed_offsets1() {
 ; CHECK-LABEL: @mixed_offsets1(
-; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, ptr [[A]], i64 -1
-; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, ptr [[B]], i64 2
-; CHECK-NEXT:    [[RES:%.*]] = icmp ne ptr [[A_OFF]], [[B_OFF]]
-; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK-NEXT:    ret i1 true
 ;
   %a = alloca i8, i32 4
   %b = alloca i8, i32 4
@@ -160,15 +148,9 @@
   ret i1 %res
 }
 
-; FIXME: Can't be equal
 define i1 @mixed_offsets2() {
 ; CHECK-LABEL: @mixed_offsets2(
-; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, ptr [[A]], i64 1
-; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, ptr [[B]], i64 -2
-; CHECK-NEXT:    [[RES:%.*]] = icmp ne ptr [[A_OFF]], [[B_OFF]]
-; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK-NEXT:    ret i1 true
 ;
   %a = alloca i8, i32 4
   %b = alloca i8, i32 4
@@ -178,15 +160,9 @@
   ret i1 %res
 }
 
-; FIXME: Can't be equal
 define i1 @negative_in_other() {
 ; CHECK-LABEL: @negative_in_other(
-; CHECK-NEXT:    [[A:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[B:%.*]] = alloca i8, i32 4, align 1
-; CHECK-NEXT:    [[A_OFF:%.*]] = getelementptr i8, ptr [[A]], i64 -3
-; CHECK-NEXT:    [[B_OFF:%.*]] = getelementptr i8, ptr [[B]], i64 -2
-; CHECK-NEXT:    [[RES:%.*]] = icmp ne ptr [[A_OFF]], [[B_OFF]]
-; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK-NEXT:    ret i1 true
 ;
   %a = alloca i8, i32 4
   %b = alloca i8, i32 4
Index: llvm/test/Transforms/InstSimplify/past-the-end.ll
===================================================================
--- llvm/test/Transforms/InstSimplify/past-the-end.ll
+++ llvm/test/Transforms/InstSimplify/past-the-end.ll
@@ -57,12 +57,7 @@
 
 define zeroext i1 @both_past_the_end_alloca() {
 ; CHECK-LABEL: @both_past_the_end_alloca(
-; CHECK:         [[M:%.*]] = alloca i32
-; CHECK-NEXT:    [[N:%.*]] = alloca i32
-; CHECK-NEXT:    [[X:%.*]] = getelementptr i32, ptr [[M]], i32 1
-; CHECK-NEXT:    [[Y:%.*]] = getelementptr i32, ptr [[N]], i32 1
-; CHECK-NEXT:    [[T:%.*]] = icmp eq ptr [[X]], [[Y]]
-; CHECK-NEXT:    ret i1 [[T]]
+; CHECK-NEXT:    ret i1 false
 ;
   %m = alloca i32
   %n = alloca i32
@@ -70,7 +65,6 @@
   %y = getelementptr i32, ptr %n, i32 1
   %t = icmp eq ptr %x, %y
   ret i1 %t
-  ; TODO: refine this
 }
 
 ; Comparing past-the-end addresses of one alloca to the base address