Index: lib/Analysis/BasicAliasAnalysis.cpp
===================================================================
--- lib/Analysis/BasicAliasAnalysis.cpp
+++ lib/Analysis/BasicAliasAnalysis.cpp
@@ -363,9 +363,12 @@
 /// particular for 32b programs with negative indices that rely on two's
 /// complement wrap-arounds for precise alias information.
 static int64_t adjustToPointerSize(int64_t Offset, unsigned PointerSize) {
-  assert(PointerSize <= 64 && "Invalid PointerSize!");
-  unsigned ShiftBits = 64 - PointerSize;
-  return (int64_t)((uint64_t)Offset << ShiftBits) >> ShiftBits;
+  if (PointerSize < 64) {
+    unsigned ShiftBits = 64 - PointerSize;
+    return (int64_t)((uint64_t)Offset << ShiftBits) >> ShiftBits;
+  } else {
+    return Offset;
+  }
 }
 
 /// If V is a symbolic pointer expression, decompose it into a base pointer
Index: test/Analysis/BasicAA/128-bit-ptr.ll
===================================================================
--- /dev/null
+++ test/Analysis/BasicAA/128-bit-ptr.ll
@@ -0,0 +1,19 @@
+; RUN: opt -S -basicaa -gvn < %s | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128-p100:128:64:64-p101:128:64:64"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i64 @test1(double addrspace(100)* addrspace(100)* %a) {
+  %p = load double addrspace(100)*, double addrspace(100)* addrspace(100)* %a
+  %e21 = getelementptr inbounds double, double addrspace(100)* %p, i128 1
+  %e2 = getelementptr inbounds double, double addrspace(100)* %e21, i128 1
+  %c2 = bitcast double addrspace(100)* %e2 to i64 addrspace(100)*
+  %d = load i64, i64 addrspace(100)* %c2
+  %sum = add i64 0, %d
+  ret i64 %sum
+; This test checks against an assertion in opt so is light on
+; checking the generated code.
+;
+; CHECK-LABEL: @test1(
+; CHECK: ret i64
+}