[Polly] Allow the IslExprBuilder to compare pointers

[jdoerfert]

ping

[jdoerfert]

Will be part of the alias checks commit

lib/CodeGen/IslExprBuilder.cpp

Value *IslExprBuilder::createOpICmp(__isl_take isl_ast_expr *Expr) {
   assert(isl_ast_expr_get_type(Expr) == isl_ast_expr_op &&
          "Expected an isl_ast_expr_op expression");
 
   Value *LHS, *RHS, *Res;
 
   LHS = create(isl_ast_expr_get_op_arg(Expr, 0));
   RHS = create(isl_ast_expr_get_op_arg(Expr, 1));
 
+  bool IsPtrType = LHS->getType()->isPointerTy();
+  assert((!IsPtrType || RHS->getType()->isPointerTy()) &&
+         "Both ICmp operators should be pointer types or none of them");
+
+  if (!IsPtrType) {
     Type *MaxType = LHS->getType();
     MaxType = getWidestType(MaxType, RHS->getType());
 
     if (MaxType != RHS->getType())
       RHS = Builder.CreateSExt(RHS, MaxType);
 
     if (MaxType != LHS->getType())
       LHS = Builder.CreateSExt(LHS, MaxType);
-
-  switch (isl_ast_expr_get_op_type(Expr)) {
-  default:
-    llvm_unreachable("Unsupported ICmp isl ast expression");
-  case isl_ast_op_eq:
-    Res = Builder.CreateICmpEQ(LHS, RHS);
-    break;
-  case isl_ast_op_le:
-    Res = Builder.CreateICmpSLE(LHS, RHS);
-    break;
-  case isl_ast_op_lt:
-    Res = Builder.CreateICmpSLT(LHS, RHS);
-    break;
-  case isl_ast_op_ge:
-    Res = Builder.CreateICmpSGE(LHS, RHS);
-    break;
-  case isl_ast_op_gt:
-    Res = Builder.CreateICmpSGT(LHS, RHS);
-    break;
   }
 
+  isl_ast_op_type OpType = isl_ast_expr_get_op_type(Expr);
+  assert(OpType >= isl_ast_op_eq && OpType <= isl_ast_op_gt &&
+         "Unsupported ICmp isl ast expression");
+  assert(isl_ast_op_eq + 5 == isl_ast_op_gt &&
+         "Isl ast op type interface changed");
+
+  CmpInst::Predicate Predicates[5][2] = {
+      {CmpInst::ICMP_EQ, CmpInst::ICMP_EQ},
+      {CmpInst::ICMP_SLE, CmpInst::ICMP_ULE},
+      {CmpInst::ICMP_SLT, CmpInst::ICMP_ULT},
+      {CmpInst::ICMP_SGE, CmpInst::ICMP_UGE},
+      {CmpInst::ICMP_SGT, CmpInst::ICMP_UGT},
+  };
+
+  Res = Builder.CreateICmp(Predicates[OpType][IsPtrType], LHS, RHS);
+
   isl_ast_expr_free(Expr);
   return Res;
 }
 
 Value *IslExprBuilder::createOpBoolean(__isl_take isl_ast_expr *Expr) {
   assert(isl_ast_expr_get_type(Expr) == isl_ast_expr_op &&
          "Expected an isl_ast_expr_op expression");