diff --git a/llvm/docs/AliasAnalysis.rst b/llvm/docs/AliasAnalysis.rst
--- a/llvm/docs/AliasAnalysis.rst
+++ b/llvm/docs/AliasAnalysis.rst
@@ -166,9 +166,25 @@
 
 The ``pointsToConstantMemory`` method returns true if and only if the analysis
 can prove that the pointer only points to unchanging memory locations
-(functions, constant global variables, and the null pointer).  This information
-can be used to refine mod/ref information: it is impossible for an unchanging
-memory location to be modified.
+(functions, constant global variables, and the null pointer). The
+``getModRefInfoMask`` function uses this to refine mod/ref information: it is
+impossible for an unchanging memory location to be modified.
+
+The ``getModRefInfoMask`` method
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The ``getModRefInfoMask`` method returns a bound on Mod/Ref information for
+the supplied pointer, based on knowledge about whether the pointer points to
+globally-constant memory (for which it returns ``NoModRef``) or
+locally-invariant memory (for which it returns ``Ref``). Locally-invariant
+memory is memory that we know is invariant for the lifetime of its SSA value,
+but not necessarily for the life of the program: for example, the memory
+pointed to by ``readonly`` ``noalias`` parameters is known-invariant for the
+duration of the corresponding function call. Given Mod/Ref information
+``MRI`` for a memory location ``Loc``, ``MRI`` can be refined with a
+statement like ``MRI &= AA.getModRefInfoMask(Loc);``. Another useful idiom is
+``isModSet(AA.getModRefInfoMask(Loc))``; this checks to see if the given
+location can be modified at all.
 
 .. _never access memory or only read memory:
 
diff --git a/llvm/include/llvm/Analysis/AliasAnalysis.h b/llvm/include/llvm/Analysis/AliasAnalysis.h
--- a/llvm/include/llvm/Analysis/AliasAnalysis.h
+++ b/llvm/include/llvm/Analysis/AliasAnalysis.h
@@ -375,6 +375,18 @@
   /// \name Simple mod/ref information
   /// @{
 
+  /// Returns a bitmask that should be unconditionally applied to the ModRef
+  /// info of a memory location. This allows us to eliminate Mod and/or Ref
+  /// from the ModRef info based on the knowledge that the memory location
+  /// points to constant and/or locally-invariant memory.
+  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc);
+
+  /// A convenience wrapper around the primary \c getModRefInfoMask
+  /// interface.
+  ModRefInfo getModRefInfoMask(const Value *P) {
+    return getModRefInfoMask(MemoryLocation::getBeforeOrAfter(P));
+  }
+
   /// Get the ModRef info associated with a pointer argument of a call. The
   /// result's bits are set to indicate the allowed aliasing ModRef kinds. Note
   /// that these bits do not necessarily account for the overall behavior of
@@ -617,6 +629,7 @@
                     AAQueryInfo &AAQI);
   bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
                               bool OrLocal = false);
+  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI);
   ModRefInfo getModRefInfo(Instruction *I, const CallBase *Call2,
                            AAQueryInfo &AAQIP);
   ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
@@ -684,6 +697,9 @@
   bool pointsToConstantMemory(const MemoryLocation &Loc, bool OrLocal = false) {
     return AA.pointsToConstantMemory(Loc, AAQI, OrLocal);
   }
+  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc) {
+    return AA.getModRefInfoMask(Loc, AAQI);
+  }
   ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc) {
     return AA.getModRefInfo(Call, Loc, AAQI);
   }
@@ -756,6 +772,13 @@
   /// \name Simple mod/ref information
   /// @{
 
+  /// Returns a bitmask that should be unconditionally applied to the ModRef
+  /// info of a memory location. This allows us to eliminate Mod and/or Ref from
+  /// the ModRef info based on the knowledge that the memory location points to
+  /// constant and/or locally-invariant memory.
+  virtual ModRefInfo getModRefInfoMask(const MemoryLocation &Loc,
+                                       AAQueryInfo &AAQI) = 0;
+
   /// Get the ModRef info associated with a pointer argument of a callsite. The
   /// result's bits are set to indicate the allowed aliasing ModRef kinds. Note
   /// that these bits do not necessarily account for the overall behavior of
@@ -809,6 +832,11 @@
     return Result.pointsToConstantMemory(Loc, AAQI, OrLocal);
   }
 
+  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc,
+                               AAQueryInfo &AAQI) override {
+    return Result.getModRefInfoMask(Loc, AAQI);
+  }
+
   ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) override {
     return Result.getArgModRefInfo(Call, ArgIdx);
   }
@@ -864,6 +892,10 @@
     return false;
   }
 
+  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI) {
+    return ModRefInfo::ModRef;
+  }
+
   ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) {
     return ModRefInfo::ModRef;
   }
diff --git a/llvm/include/llvm/Analysis/BasicAliasAnalysis.h b/llvm/include/llvm/Analysis/BasicAliasAnalysis.h
--- a/llvm/include/llvm/Analysis/BasicAliasAnalysis.h
+++ b/llvm/include/llvm/Analysis/BasicAliasAnalysis.h
@@ -79,6 +79,12 @@
   bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
                               bool OrLocal);
 
+  /// Returns a bitmask that should be unconditionally applied to the ModRef
+  /// info of a memory location. This allows us to eliminate Mod and/or Ref
+  /// from the ModRef info based on the knowledge that the memory location
+  /// points to constant and/or locally-invariant memory.
+  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI);
+
   /// Get the location associated with a pointer argument of a callsite.
   ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx);
 
diff --git a/llvm/include/llvm/Analysis/TypeBasedAliasAnalysis.h b/llvm/include/llvm/Analysis/TypeBasedAliasAnalysis.h
--- a/llvm/include/llvm/Analysis/TypeBasedAliasAnalysis.h
+++ b/llvm/include/llvm/Analysis/TypeBasedAliasAnalysis.h
@@ -42,6 +42,7 @@
                     AAQueryInfo &AAQI);
   bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
                               bool OrLocal);
+  ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI);
   MemoryEffects getMemoryEffects(const CallBase *Call, AAQueryInfo &AAQI);
   MemoryEffects getMemoryEffects(const Function *F);
   ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -162,6 +162,26 @@
   return false;
 }
 
+ModRefInfo AAResults::getModRefInfoMask(const MemoryLocation &Loc) {
+  SimpleAAQueryInfo AAQIP(*this);
+  return getModRefInfoMask(Loc, AAQIP);
+}
+
+ModRefInfo AAResults::getModRefInfoMask(const MemoryLocation &Loc,
+                                        AAQueryInfo &AAQI) {
+  ModRefInfo Result = ModRefInfo::ModRef;
+
+  for (const auto &AA : AAs) {
+    Result &= AA->getModRefInfoMask(Loc, AAQI);
+
+    // Early-exit the moment we reach the bottom of the lattice.
+    if (isNoModRef(Result))
+      return ModRefInfo::NoModRef;
+  }
+
+  return Result;
+}
+
 ModRefInfo AAResults::getArgModRefInfo(const CallBase *Call, unsigned ArgIdx) {
   ModRefInfo Result = ModRefInfo::ModRef;
 
@@ -253,10 +273,11 @@
 
   Result &= ArgMR | OtherMR;
 
-  // If Loc is a constant memory location, the call definitely could not
+  // Apply the ModRef mask. This ensures that if Loc is a constant memory
+  // location, we take into account the fact that the call definitely could not
   // modify the memory location.
-  if (isModSet(Result) && pointsToConstantMemory(Loc, AAQI, /*OrLocal*/ false))
-    Result &= ModRefInfo::Ref;
+  if (!isNoModRef(Result))
+    Result &= getModRefInfoMask(Loc);
 
   return Result;
 }
@@ -510,9 +531,11 @@
     if (AR == AliasResult::NoAlias)
       return ModRefInfo::NoModRef;
 
-    // If the pointer is a pointer to constant memory, then it could not have
-    // been modified by this store.
-    if (pointsToConstantMemory(Loc, AAQI))
+    // Examine the ModRef mask. If Mod isn't present, then return NoModRef.
+    // This ensures that if Loc is a constant memory location, we take into
+    // account the fact that the store definitely could not modify the memory
+    // location.
+    if (!isModSet(getModRefInfoMask(Loc)))
       return ModRefInfo::NoModRef;
   }
 
@@ -529,11 +552,10 @@
 ModRefInfo AAResults::getModRefInfo(const FenceInst *S,
                                     const MemoryLocation &Loc,
                                     AAQueryInfo &AAQI) {
-  // If we know that the location is a constant memory location, the fence
-  // cannot modify this location.
-  if (Loc.Ptr && pointsToConstantMemory(Loc, AAQI))
-    return ModRefInfo::Ref;
-  return ModRefInfo::ModRef;
+  // All we know about a fence instruction is what we get from the ModRef
+  // mask: if Loc is a constant memory location, the fence definitely could
+  // not modify it.
+  return getModRefInfoMask(Loc);
 }
 
 ModRefInfo AAResults::getModRefInfo(const VAArgInst *V,
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -820,6 +820,31 @@
   return false;
 }
 
+ModRefInfo BasicAAResult::getModRefInfoMask(const MemoryLocation &Loc,
+                                            AAQueryInfo &AAQI) {
+  if (Loc.Ptr) {
+    // If the location points to globally-constant memory, there can be no
+    // visible memory effects.
+    if (pointsToConstantMemory(Loc, AAQI, false))
+      return ModRefInfo::NoModRef;
+
+    // If the location points to memory that is known to be invariant for
+    // the life of the underlying SSA value, then we can exclude Mod from
+    // the set of valid memory effects.
+    //
+    // An argument that is marked readonly and noalias is known to be
+    // invariant while that function is executing.
+    if (const Argument *Arg =
+            dyn_cast<Argument>(getUnderlyingObject(Loc.Ptr))) {
+      if (Arg->hasNoAliasAttr() && Arg->hasAttribute(Attribute::ReadOnly))
+        return ModRefInfo::Ref;
+    }
+  }
+
+  // Otherwise, forward to the base AAResult.
+  return AAResultBase::getModRefInfoMask(Loc, AAQI);
+}
+
 ModRefInfo BasicAAResult::getArgModRefInfo(const CallBase *Call,
                                            unsigned ArgIdx) {
   // Checking for known builtin intrinsics and target library functions.
diff --git a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
--- a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -525,7 +525,7 @@
       }
 
       // Stores don't alias loads from read-only memory.
-      if (BatchAA.pointsToConstantMemory(LoadLoc))
+      if (!isModSet(BatchAA.getModRefInfoMask(LoadLoc)))
         continue;
 
       // Stores depend on may/must aliased loads.
diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp
--- a/llvm/lib/Analysis/MemorySSA.cpp
+++ b/llvm/lib/Analysis/MemorySSA.cpp
@@ -378,9 +378,10 @@
                                                    const Instruction *I) {
   // If the memory can't be changed, then loads of the memory can't be
   // clobbered.
-  if (auto *LI = dyn_cast<LoadInst>(I))
+  if (auto *LI = dyn_cast<LoadInst>(I)) {
     return I->hasMetadata(LLVMContext::MD_invariant_load) ||
-           AA.pointsToConstantMemory(MemoryLocation::get(LI));
+           !isModSet(AA.getModRefInfoMask(MemoryLocation::get(LI)));
+  }
   return false;
 }
 
diff --git a/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp b/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
--- a/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/TypeBasedAliasAnalysis.cpp
@@ -404,6 +404,17 @@
   return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
 }
 
+ModRefInfo TypeBasedAAResult::getModRefInfoMask(const MemoryLocation &Loc,
+                                                AAQueryInfo &AAQI) {
+  // If the location points to globally-constant memory, there can be no
+  // visible memory effects.
+  if (Loc.Ptr && pointsToConstantMemory(Loc, AAQI, false))
+    return ModRefInfo::NoModRef;
+
+  // Otherwise, forward to the base.
+  return AAResultBase::getModRefInfoMask(Loc, AAQI);
+}
+
 MemoryEffects TypeBasedAAResult::getMemoryEffects(const CallBase *Call,
                                                   AAQueryInfo &AAQI) {
   if (!EnableTBAA)
diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -143,6 +143,9 @@
     // Ignore accesses to local memory.
     if (AAR.pointsToConstantMemory(Loc, /*OrLocal=*/true))
       return;
+    // Ignore accesses to memory that we know is invariant.
+    if (!isModSet(AAR.getModRefInfoMask(Loc)))
+      return;
 
     const Value *UO = getUnderlyingObject(Loc.Ptr);
     assert(!isa<AllocaInst>(UO) &&
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -135,7 +135,7 @@
   // If we have a store to a location which is known constant, we can conclude
   // that the store must be storing the constant value (else the memory
   // wouldn't be constant), and this must be a noop.
-  if (AA->pointsToConstantMemory(MI->getDest())) {
+  if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) {
     // Set the size of the copy to 0, it will be deleted on the next iteration.
     MI->setLength(Constant::getNullValue(MI->getLength()->getType()));
     return MI;
@@ -252,7 +252,7 @@
   // If we have a store to a location which is known constant, we can conclude
   // that the store must be storing the constant value (else the memory
   // wouldn't be constant), and this must be a noop.
-  if (AA->pointsToConstantMemory(MI->getDest())) {
+  if (!isModSet(AA->getModRefInfoMask(MI->getDest()))) {
     // Set the size of the copy to 0, it will be deleted on the next iteration.
     MI->setLength(Constant::getNullValue(MI->getLength()->getType()));
     return MI;
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -128,8 +128,8 @@
       // If the memintrinsic isn't using the alloca as the dest, reject it.
       if (U.getOperandNo() != 0) return false;
 
-      // If the source of the memcpy/move is not a constant global, reject it.
-      if (!AA->pointsToConstantMemory(MI->getSource()))
+      // If the source of the memcpy/move is not constant, reject it.
+      if (isModSet(AA->getModRefInfoMask(MI->getSource())))
         return false;
 
       // Otherwise, the transform is safe.  Remember the copy instruction.
@@ -1372,7 +1372,7 @@
   // If we have a store to a location which is known constant, we can conclude
   // that the store must be storing the constant value (else the memory
   // wouldn't be constant), and this must be a noop.
-  if (AA->pointsToConstantMemory(Ptr))
+  if (!isModSet(AA->getModRefInfoMask(Ptr)))
     return eraseInstFromFunction(SI);
 
   // Do really simple DSE, to catch cases where there are several consecutive
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -1161,7 +1161,7 @@
 
     // Loads from constant memory are always safe to move, even if they end up
     // in the same alias set as something that ends up being modified.
-    if (AA->pointsToConstantMemory(LI->getOperand(0)))
+    if (!isModSet(AA->getModRefInfoMask(LI->getOperand(0))))
       return true;
     if (LI->hasMetadata(LLVMContext::MD_invariant_load))
       return true;
diff --git a/llvm/lib/Transforms/Scalar/LoopPredication.cpp b/llvm/lib/Transforms/Scalar/LoopPredication.cpp
--- a/llvm/lib/Transforms/Scalar/LoopPredication.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopPredication.cpp
@@ -569,7 +569,7 @@
   if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S))
     if (const auto *LI = dyn_cast<LoadInst>(U->getValue()))
       if (LI->isUnordered() && L->hasLoopInvariantOperands(LI))
-        if (AA->pointsToConstantMemory(LI->getOperand(0)) ||
+        if (!isModSet(AA->getModRefInfoMask(LI->getOperand(0))) ||
             LI->hasMetadata(LLVMContext::MD_invariant_load))
           return true;
   return false;
diff --git a/llvm/test/Analysis/BasicAA/constant-memory.ll b/llvm/test/Analysis/BasicAA/constant-memory.ll
--- a/llvm/test/Analysis/BasicAA/constant-memory.ll
+++ b/llvm/test/Analysis/BasicAA/constant-memory.ll
@@ -4,18 +4,16 @@
 
 declare void @dummy()
 
-; FIXME: This could be NoModRef
 ; CHECK-LABEL: Function: basic
-; CHECK: Just Ref: Ptr: i32* @c	<->  call void @dummy()
+; CHECK: NoModRef: Ptr: i32* @c	<->  call void @dummy()
 define void @basic(ptr %p) {
   call void @dummy()
   load i32, ptr @c
   ret void
 }
 
-; FIXME: This could be NoModRef
 ; CHECK-LABEL: Function: recphi
-; CHECK: Just Ref: Ptr: i32* %p	<->  call void @dummy()
+; CHECK: NoModRef: Ptr: i32* %p	<->  call void @dummy()
 define void @recphi() {
 entry:
   br label %loop
diff --git a/llvm/test/Analysis/BasicAA/pr18573.ll b/llvm/test/Analysis/BasicAA/pr18573.ll
--- a/llvm/test/Analysis/BasicAA/pr18573.ll
+++ b/llvm/test/Analysis/BasicAA/pr18573.ll
@@ -8,7 +8,7 @@
 declare <8 x float> @llvm.x86.avx2.gather.d.ps.256(<8 x float>, i8*, <8 x i32>, <8 x float>, i8) #0
 
 ; Function Attrs: nounwind
-define <8 x float> @foo1(i8* noalias readonly %arr.ptr, <8 x i32>* noalias readonly %vix.ptr, i8* noalias %t2.ptr) #1 {
+define <8 x float> @foo1(i8* readonly %arr.ptr, <8 x i32>* noalias readonly %vix.ptr, i8* noalias %t2.ptr) #1 {
 allocas:
   %vix = load <8 x i32>, <8 x i32>* %vix.ptr, align 4
   %t1.ptr = getelementptr i8, i8* %arr.ptr, i8 4
diff --git a/llvm/test/Analysis/BasicAA/readonly-noalias.ll b/llvm/test/Analysis/BasicAA/readonly-noalias.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Analysis/BasicAA/readonly-noalias.ll
@@ -0,0 +1,13 @@
+; Tests that readonly noalias implies !Mod.
+;
+; RUN: opt < %s -passes=aa-eval -print-all-alias-modref-info 2>&1 | FileCheck %s
+
+declare void @foo()
+
+; CHECK-LABEL: Function: basic
+; CHECK: NoModRef: Ptr: i32* %p <->  call void @foo()
+define void @basic(ptr readonly noalias %p) {
+    call void @foo()
+    load i32, ptr %p
+    ret void
+}
diff --git a/llvm/test/Transforms/InstCombine/store.ll b/llvm/test/Transforms/InstCombine/store.ll
--- a/llvm/test/Transforms/InstCombine/store.ll
+++ b/llvm/test/Transforms/InstCombine/store.ll
@@ -336,6 +336,14 @@
   ret void
 }
 
+; Delete stores to readonly noalias pointers.
+define void @store_to_readonly_noalias(ptr readonly noalias %0) {
+; CHECK-LABEL: @store_to_readonly_noalias(
+; CHECK-NEXT:    ret void
+  store i32 3, ptr %0, align 4
+  ret void
+}
+
 !0 = !{!4, !4, i64 0}
 !1 = !{!"omnipotent char", !2}
 !2 = !{!"Simple C/C++ TBAA"}
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll b/llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll
--- a/llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/sve-gather-scatter.ll
@@ -292,7 +292,7 @@
 
 
 
-define void @gather_nxv4i32_ind64_stride2(float* noalias nocapture readonly %a, float* noalias nocapture readonly %b, i64 %n) #0 {
+define void @gather_nxv4i32_ind64_stride2(float* noalias nocapture %a, float* noalias nocapture readonly %b, i64 %n) #0 {
 ; CHECK-LABEL: @gather_nxv4i32_ind64_stride2(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
diff --git a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
--- a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
+++ b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
@@ -572,15 +572,15 @@
 ; void load_gap_reverse(struct pair *P1, struct pair *P2, int X) {
 ;   for (int i = 1023; i >= 0; i--) {
 ;     int a = X + i;
-;     int b = A[i].y - i;
-;     B[i].x = a;
+;     int b = B[i].y - i;
+;     A[i].x = a;
 ;     B[i].y = b;
 ;   }
 ; }
 
 
 %pair = type { i64, i64 }
-define void @load_gap_reverse(%pair* noalias nocapture readonly %P1, %pair* noalias nocapture readonly %P2, i64 %X) {
+define void @load_gap_reverse(%pair* noalias nocapture %P1, %pair* noalias nocapture %P2, i64 %X) {
 ; CHECK-LABEL: @load_gap_reverse(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]