2 files changed, 75 insertions, 9 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index c295f599a37..370155873c0 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -7617,6 +7617,15 @@ QualType ASTContext::mergeTypes(QualType LHS, QualType RHS,
   Qualifiers LQuals = LHSCan.getLocalQualifiers();
   Qualifiers RQuals = RHSCan.getLocalQualifiers();
   if (LQuals != RQuals) {
+    if (getLangOpts().OpenCL) {
+      if (LHS.getUnqualifiedType() != RHS.getUnqualifiedType() ||
+          LQuals.getCVRQualifiers() != RQuals.getCVRQualifiers())
+        return QualType();
+      if (LQuals.isAddressSpaceSupersetOf(RQuals))
+        return LHS;
+      if (RQuals.isAddressSpaceSupersetOf(LQuals))
+        return RHS;
+    }
     // If any of these qualifiers are different, we have a type
     // mismatch.
     if (LQuals.getCVRQualifiers() != RQuals.getCVRQualifiers() ||
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 32e189a843e..561e4777e6a 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6193,30 +6193,87 @@ static QualType checkConditionalPointerCompatibility(Sema &S, ExprResult &LHS,
   lhptee = S.Context.getQualifiedType(lhptee.getUnqualifiedType(), lhQual);
   rhptee = S.Context.getQualifiedType(rhptee.getUnqualifiedType(), rhQual);
 
+  // For OpenCL:
+  // 1. If LHS and RHS types match exactly and:
+  //  (a) AS match => use standard C rules, no bitcast or addrspacecast
+  //  (b) AS overlap => generate addrspacecast
+  //  (c) AS don't overlap => give an error
+  // 2. if LHS and RHS types don't match:
+  //  (a) AS match => use standard C rules, generate bitcast
+  //  (b) AS overlap => generate addrspacecast instead of bitcast
+  //  (c) AS don't overlap => give an error
+
+  // For OpenCL, non-null composite type is returned only for cases 1a and 1b.
   QualType CompositeTy = S.Context.mergeTypes(lhptee, rhptee);
 
+  // OpenCL cases 1c, 2a, 2b, and 2c.
   if (CompositeTy.isNull()) {
-    S.Diag(Loc, diag::ext_typecheck_cond_incompatible_pointers)
-      << LHSTy << RHSTy << LHS.get()->getSourceRange()
-      << RHS.get()->getSourceRange();
     // In this situation, we assume void* type. No especially good
     // reason, but this is what gcc does, and we do have to pick
     // to get a consistent AST.
-    QualType incompatTy = S.Context.getPointerType(S.Context.VoidTy);
-    LHS = S.ImpCastExprToType(LHS.get(), incompatTy, CK_BitCast);
-    RHS = S.ImpCastExprToType(RHS.get(), incompatTy, CK_BitCast);
+    QualType incompatTy;
+    if (S.getLangOpts().OpenCL) {
+      // OpenCL v1.1 s6.5 - Conversion between pointers to distinct address
+      // spaces is disallowed.
+      unsigned ResultAddrSpace;
+      if (lhQual.isAddressSpaceSupersetOf(rhQual)) {
+        // Cases 2a and 2b.
+        ResultAddrSpace = lhQual.getAddressSpace();
+      } else if (rhQual.isAddressSpaceSupersetOf(lhQual)) {
+        // Cases 2a and 2b.
+        ResultAddrSpace = rhQual.getAddressSpace();
+      } else {
+        // Cases 1c and 2c.
+        S.Diag(Loc,
+               diag::err_typecheck_op_on_nonoverlapping_address_space_pointers)
+            << LHSTy << RHSTy << 2 << LHS.get()->getSourceRange()
+            << RHS.get()->getSourceRange();
+        return QualType();
+      }
+
+      // Continue handling cases 2a and 2b.
+      incompatTy = S.Context.getPointerType(
+          S.Context.getAddrSpaceQualType(S.Context.VoidTy, ResultAddrSpace));
+      LHS = S.ImpCastExprToType(LHS.get(), incompatTy,
+                                (lhQual.getAddressSpace() != ResultAddrSpace)
+                                    ? CK_AddressSpaceConversion /* 2b */
+                                    : CK_BitCast /* 2a */);
+      RHS = S.ImpCastExprToType(RHS.get(), incompatTy,
+                                (rhQual.getAddressSpace() != ResultAddrSpace)
+                                    ? CK_AddressSpaceConversion /* 2b */
+                                    : CK_BitCast /* 2a */);
+    } else {
+      S.Diag(Loc, diag::ext_typecheck_cond_incompatible_pointers)
+          << LHSTy << RHSTy << LHS.get()->getSourceRange()
+          << RHS.get()->getSourceRange();
+      incompatTy = S.Context.getPointerType(S.Context.VoidTy);
+      LHS = S.ImpCastExprToType(LHS.get(), incompatTy, CK_BitCast);
+      RHS = S.ImpCastExprToType(RHS.get(), incompatTy, CK_BitCast);
+    }
     return incompatTy;
   }
 
   // The pointer types are compatible.
   QualType ResultTy = CompositeTy.withCVRQualifiers(MergedCVRQual);
+  auto LHSCastKind = CK_BitCast, RHSCastKind = CK_BitCast;
   if (IsBlockPointer)
     ResultTy = S.Context.getBlockPointerType(ResultTy);
-  else
+  else {
+    // Cases 1a and 1b for OpenCL.
+    auto ResultAddrSpace = ResultTy.getQualifiers().getAddressSpace();
+    LHSCastKind = lhQual.getAddressSpace() == ResultAddrSpace
+                      ? CK_BitCast /* 1a */
+                      : CK_AddressSpaceConversion /* 1b */;
+    RHSCastKind = rhQual.getAddressSpace() == ResultAddrSpace
+                      ? CK_BitCast /* 1a */
+                      : CK_AddressSpaceConversion /* 1b */;
     ResultTy = S.Context.getPointerType(ResultTy);
+  }
 
-  LHS = S.ImpCastExprToType(LHS.get(), ResultTy, CK_BitCast);
-  RHS = S.ImpCastExprToType(RHS.get(), ResultTy, CK_BitCast);
+  // For case 1a of OpenCL, S.ImpCastExprToType will not insert bitcast
+  // if the target type does not change.
+  LHS = S.ImpCastExprToType(LHS.get(), ResultTy, LHSCastKind);
+  RHS = S.ImpCastExprToType(RHS.get(), ResultTy, RHSCastKind);
   return ResultTy;
 }