Index: llvm/lib/Analysis/BasicAliasAnalysis.cpp
===================================================================
--- llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -1666,8 +1666,10 @@
           // result of this PHI node (e.g. in a loop). If this is the case, we
           // would recurse and always get a MayAlias. Handle this case specially
           // below.
-          if (PV1GEP->getPointerOperand() == PN && PV1GEP->getNumIndices() == 1 &&
-              isa<ConstantInt>(PV1GEP->idx_begin())) {
+          if (PV1GEP->getPointerOperand() == PN &&
+              PV1GEP->getNumIndices() == 1 &&
+              isa<ConstantInt>(PV1GEP->idx_begin()) &&
+              cast<ConstantInt>(PV1GEP->idx_begin())->getSExtValue() >= 0) {
             isRecursive = true;
             continue;
           }
@@ -1693,8 +1695,10 @@
           // result of this PHI node (e.g. in a loop). If this is the case, we
           // would recurse and always get a MayAlias. Handle this case specially
           // below.
-          if (PV1GEP->getPointerOperand() == PN && PV1GEP->getNumIndices() == 1 &&
-              isa<ConstantInt>(PV1GEP->idx_begin())) {
+          if (PV1GEP->getPointerOperand() == PN &&
+              PV1GEP->getNumIndices() == 1 &&
+              isa<ConstantInt>(PV1GEP->idx_begin()) &&
+              cast<ConstantInt>(PV1GEP->idx_begin())->getSExtValue() >= 0) {
             isRecursive = true;
             continue;
           }
Index: llvm/test/Analysis/BasicAA/recphi.ll
===================================================================
--- llvm/test/Analysis/BasicAA/recphi.ll
+++ llvm/test/Analysis/BasicAA/recphi.ll
@@ -92,8 +92,8 @@
 ; CHECK:         NoAlias:      i32* %arrayidx1, i8* %0
 ; CHECK:         NoAlias:      i32* %arrayidx, i32* %arrayidx1
 ; CHECK:         MayAlias:     [10 x i32]* %tab, i32* %p.addr.05.i
-; CHECK:         NoAlias:      i32* %p.addr.05.i, i8* %0
-; CHECK:         NoAlias:      i32* %arrayidx, i32* %p.addr.05.i
+; CHECK:         MayAlias:     i32* %p.addr.05.i, i8* %0
+; CHECK:         MayAlias:     i32* %arrayidx, i32* %p.addr.05.i
 ; CHECK:         MayAlias:     i32* %arrayidx1, i32* %p.addr.05.i
 ; CHECK:         MayAlias:     [10 x i32]* %tab, i32* %incdec.ptr.i
 ; CHECK:         MayAlias:     i32* %incdec.ptr.i, i8* %0
@@ -141,17 +141,17 @@
 ; CHECK:         NoAlias:      [3 x i16]* %int_arr.10, i16** %argv.6.par
 ; CHECK:         NoAlias:      i16* %_tmp1, i16** %argv.6.par
 ; CHECK:         PartialAlias: [3 x i16]* %int_arr.10, i16* %_tmp1
-; CHECK:         NoAlias:      i16* %ls1.9.0, i16** %argv.6.par
+; CHECK:         MayAlias:     i16* %ls1.9.0, i16** %argv.6.par
 ; CHECK:         MayAlias:     [3 x i16]* %int_arr.10, i16* %ls1.9.0
 ; CHECK:         MayAlias:     i16* %_tmp1, i16* %ls1.9.0
-; CHECK:         NoAlias:      i16* %_tmp7, i16** %argv.6.par
+; CHECK:         MayAlias:     i16* %_tmp7, i16** %argv.6.par
 ; CHECK:         MayAlias:     [3 x i16]* %int_arr.10, i16* %_tmp7
 ; CHECK:         MayAlias:     i16* %_tmp1, i16* %_tmp7
 ; CHECK:         NoAlias:      i16* %_tmp7, i16* %ls1.9.0
 ; CHECK:         NoAlias:      i16* %_tmp11, i16** %argv.6.par
 ; CHECK:         PartialAlias: [3 x i16]* %int_arr.10, i16* %_tmp11
 ; CHECK:         NoAlias:      i16* %_tmp1, i16* %_tmp11
-; CHECK:         NoAlias:      i16* %_tmp11, i16* %ls1.9.0
+; CHECK:         MayAlias:     i16* %_tmp11, i16* %ls1.9.0
 ; CHECK:         MayAlias:     i16* %_tmp11, i16* %_tmp7
 ; CHECK:         Both ModRef:  Ptr: i16** %argv.6.par  <->  %_tmp16 = call i16 @call(i32 %_tmp13)
 ; CHECK:         NoModRef:  Ptr: [3 x i16]* %int_arr.10        <->  %_tmp16 = call i16 @call(i32 %_tmp13)