Index: lib/Analysis/ScopDetection.cpp
===================================================================
--- lib/Analysis/ScopDetection.cpp
+++ lib/Analysis/ScopDetection.cpp
@@ -192,6 +192,12 @@
                    cl::Hidden, cl::init(false), cl::ZeroOrMore,
                    cl::cat(PollyCategory));
 
+static cl::opt<bool>
+    AllowNonAffineRead("polly-allow-nonaffine-read",
+                       cl::desc("Allow non-affine read functions in arrays"),
+                       cl::Hidden, cl::init(true), cl::ZeroOrMore,
+                       cl::cat(PollyCategory));
+
 static cl::opt<bool>
     AllowModrefCall("polly-allow-modref-calls",
                     cl::desc("Allow functions with known modref behavior"),
@@ -958,7 +964,8 @@
       const Instruction *Insn = Pair.first;
       const SCEV *AF = Pair.second;
 
-      if (!isAffine(AF, Scope, Context)) {
+      if (!isAffine(AF, Scope, Context) &&
+          (Insn->mayWriteToMemory() || !AllowNonAffineRead)) {
         invalid<ReportNonAffineAccess>(Context, /*Assert=*/true, AF, Insn,
                                        BaseValue);
         if (!KeepGoing)
@@ -1013,10 +1020,13 @@
     // (Possibly) report non affine access
     if (IsNonAffine) {
       BasePtrHasNonAffine = true;
-      if (!AllowNonAffine)
+      bool AllowThisNonAffine =
+          AllowNonAffine || (!Insn->mayWriteToMemory() && AllowNonAffineRead);
+
+      if (!AllowThisNonAffine)
         invalid<ReportNonAffineAccess>(Context, /*Assert=*/true, Pair.second,
                                        Insn, BaseValue);
-      if (!KeepGoing && !AllowNonAffine)
+      if (!KeepGoing && !AllowThisNonAffine)
         return false;
     }
   }
@@ -1124,7 +1134,8 @@
     if (!IsAffine || hasIVParams(AF))
       Context.NonAffineAccesses.insert(
           std::make_pair(BP, LI.getLoopFor(Inst->getParent())));
-  } else if (!AllowNonAffine && !IsAffine) {
+  } else if (!IsAffine && !AllowNonAffine &&
+             (Inst->mayWriteToMemory() || !AllowNonAffineRead)) {
     return invalid<ReportNonAffineAccess>(Context, /*Assert=*/true, AF, Inst,
                                           BV);
   }
Index: test/Isl/CodeGen/two-loops-right-after-each-other-2.ll
===================================================================
--- test/Isl/CodeGen/two-loops-right-after-each-other-2.ll
+++ test/Isl/CodeGen/two-loops-right-after-each-other-2.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-codegen -polly-allow-nonaffine-read=0 -S < %s | FileCheck %s
 
 ; CHECK:       polly.merge_new_and_old:
 ; CHECK-NEXT:    merge = phi
Index: test/ScopDetect/allow-nonaffine-read.ll
===================================================================
--- /dev/null
+++ test/ScopDetect/allow-nonaffine-read.ll
@@ -0,0 +1,40 @@
+; RUN: opt %loadPolly -polly-detect -polly-allow-nonaffine-read=1 -analyze < %s | FileCheck %s -match-full-lines
+;
+; The non-affine lookup in the loop body must be allowed.
+;
+; for (int j = 0; j < n; j += 1) {
+;   int idx = A[j];
+;   double val = B[idx];
+;   C[0] = val;
+; }
+;
+define void @func(i32 %n, i32* noalias nonnull %A, double* noalias nonnull %B, double* noalias nonnull %C) {
+entry:
+  br label %for
+
+for:
+  %j = phi i32 [0, %entry], [%j.inc, %inc]
+  %j.cmp = icmp slt i32 %j, %n
+  br i1 %j.cmp, label %body, label %exit
+
+    body:
+      %idxidx = getelementptr inbounds i32, i32* %A, i32 %j
+      %idx = load i32, i32* %idxidx
+      %validx = getelementptr inbounds double, double* %B, i32 %idx
+      %val = load double, double* %validx
+      store double %val, double* %C
+      br label %inc
+
+inc:
+  %j.inc = add nuw nsw i32 %j, 1
+  br label %for
+
+exit:
+  br label %return
+
+return:
+  ret void
+}
+
+
+; CHECK: Valid Region for Scop: for => return
Index: test/ScopDetect/multidim.ll
===================================================================
--- test/ScopDetect/multidim.ll
+++ test/ScopDetect/multidim.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-detect -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-detect -polly-allow-nonaffine-read=0 -analyze < %s | FileCheck %s
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 
 ; CHECK: Valid Region for Scop: bb19 => bb20
Index: test/ScopDetect/non-affine-loop.ll
===================================================================
--- test/ScopDetect/non-affine-loop.ll
+++ test/ScopDetect/non-affine-loop.ll
@@ -2,7 +2,7 @@
 ; RUN:     -polly-allow-nonaffine-loops=false \
 ; RUN:     -analyze < %s | FileCheck %s --check-prefix=REJECTNONAFFINELOOPS
 ; RUN: opt %loadPolly -polly-detect -polly-allow-nonaffine-branches \
-; RUN:     -polly-allow-nonaffine-loops=true \
+; RUN:     -polly-allow-nonaffine-loops=true -polly-allow-nonaffine-read=0 \
 ; RUN:     -analyze < %s | FileCheck %s --check-prefix=ALLOWNONAFFINELOOPS
 ; RUN: opt %loadPolly -polly-detect -polly-allow-nonaffine-branches \
 ; RUN:     -polly-allow-nonaffine-loops=false -polly-allow-nonaffine \
Index: test/ScopDetect/parametric-multiply-in-scev-2.ll
===================================================================
--- test/ScopDetect/parametric-multiply-in-scev-2.ll
+++ test/ScopDetect/parametric-multiply-in-scev-2.ll
@@ -1,4 +1,4 @@
-; RUN: opt %loadPolly -polly-detect -analyze < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-detect -polly-allow-nonaffine-read=0 -analyze < %s | FileCheck %s
 
 
 ; CHECK-NOT: Valid Region
Index: test/ScopDetectionDiagnostics/ReportMultipleNonAffineAccesses.ll
===================================================================
--- test/ScopDetectionDiagnostics/ReportMultipleNonAffineAccesses.ll
+++ test/ScopDetectionDiagnostics/ReportMultipleNonAffineAccesses.ll
@@ -1,9 +1,9 @@
-; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-detect-track-failures -polly-detect -analyze < %s 2>&1| FileCheck %s
-; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-detect-track-failures -polly-detect -polly-delinearize=false -polly-detect-keep-going -analyze < %s 2>&1| FileCheck %s -check-prefix=ALL
-; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-detect-track-failures -polly-detect -analyze < %s 2>&1| FileCheck %s -check-prefix=DELIN
-; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-detect-track-failures -polly-detect -polly-detect-keep-going -analyze < %s 2>&1| FileCheck %s -check-prefix=DELIN-ALL
-; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-detect-track-failures -polly-detect -polly-allow-nonaffine -analyze < %s 2>&1| FileCheck %s -check-prefix=NONAFFINE
-; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-detect-track-failures -polly-detect -polly-allow-nonaffine -analyze < %s 2>&1| FileCheck %s -check-prefix=NONAFFINE
+; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-allow-nonaffine-read=0 -polly-detect-track-failures -polly-detect -analyze < %s 2>&1| FileCheck %s
+; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-allow-nonaffine-read=0 -polly-detect-track-failures -polly-detect -polly-delinearize=false -polly-detect-keep-going -analyze < %s 2>&1| FileCheck %s -check-prefix=ALL
+; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-allow-nonaffine-read=0 -polly-detect-track-failures -polly-detect -analyze < %s 2>&1| FileCheck %s -check-prefix=DELIN
+; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-allow-nonaffine-read=0 -polly-detect-track-failures -polly-detect -polly-detect-keep-going -analyze < %s 2>&1| FileCheck %s -check-prefix=DELIN-ALL
+; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-allow-nonaffine-read=0 -polly-detect-track-failures -polly-detect -polly-allow-nonaffine -analyze < %s 2>&1| FileCheck %s -check-prefix=NONAFFINE
+; RUN: opt %loadPolly -basicaa -pass-remarks-missed="polly-detect" -polly-allow-nonaffine-read=0 -polly-detect-track-failures -polly-detect -polly-allow-nonaffine -analyze < %s 2>&1| FileCheck %s -check-prefix=NONAFFINE
 
 ;  1 void manyaccesses(float A[restrict], long n, float B[restrict][n])
 ;  2 {