Merge pull request #2802 from advikkabra/empty-membership

Prevent the hashing function being called when capacity is zero

Author: czgdp1807

integration_tests/test_membership_01.py

@@ -6,6 +6,9 @@ def test_int_dict():
     i = 4
     assert (i in a)
 
+    a = {}
+    assert (1 not in a)
+
 def test_str_dict():
     a: dict[str, str] = {'a':'1', 'b':'2', 'c':'3'}
     i: str
@@ -14,6 +17,9 @@ def test_str_dict():
     i = 'c'
     assert (i in a)
 
+    a = {}
+    assert ('a' not in a)
+
 def test_int_set():
     a: set[i32] = {1, 2, 3, 4}
     i: i32
@@ -22,6 +28,9 @@ def test_int_set():
     i = 4
     assert (i in a)
 
+    a = set()
+    assert (1 not in a)
+
 def test_str_set():
     a: set[str] = {'a', 'b', 'c', 'e', 'f'}
     i: str
@@ -30,6 +39,9 @@ def test_str_set():
     i = 'c'
     assert (i in a)
 
+    a = set()
+    assert ('a' not in a)
+
 test_int_dict()
 test_str_dict()
 test_int_set()

src/libasr/codegen/asr_to_llvm.cpp

@@ -1726,9 +1726,17 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
         ptr_loads = ptr_loads_copy;
         llvm::Value *capacity = LLVM::CreateLoad(*builder,
             llvm_utils->dict_api->get_pointer_to_capacity(right));
-        llvm::Value *key_hash = llvm_utils->dict_api->get_key_hash(capacity, left, dict_type->m_key_type, *module);
-
-        tmp = llvm_utils->dict_api->resolve_collision_for_read_with_bound_check(right, key_hash, left, *module, dict_type->m_key_type, dict_type->m_value_type, true);
+        get_builder0();
+        llvm::AllocaInst *res = builder0.CreateAlloca(llvm::Type::getInt1Ty(context), nullptr);
+        llvm_utils->create_if_else(builder->CreateICmpEQ(
+            capacity, llvm::ConstantInt::get(llvm::Type::getInt32Ty(context), llvm::APInt(32, 0))),
+        [&]() {
+            LLVM::CreateStore(*builder, llvm::ConstantInt::get(llvm::Type::getInt1Ty(context), llvm::APInt(1, 0)), res);
+        }, [&]() {
+            llvm::Value *key_hash = llvm_utils->dict_api->get_key_hash(capacity, left, dict_type->m_key_type, *module);
+            LLVM::CreateStore(*builder, llvm_utils->dict_api->resolve_collision_for_read_with_bound_check(right, key_hash, left, *module, dict_type->m_key_type, dict_type->m_value_type, true), res);
+        });
+        tmp = LLVM::CreateLoad(*builder, res);
     }
 
     void visit_SetContains(const ASR::SetContains_t &x) {
@@ -1748,9 +1756,17 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
         ptr_loads = ptr_loads_copy;
         llvm::Value *capacity = LLVM::CreateLoad(*builder,
             llvm_utils->set_api->get_pointer_to_capacity(right));
-        llvm::Value *el_hash = llvm_utils->set_api->get_el_hash(capacity, left, el_type, *module);
-
-        tmp = llvm_utils->set_api->resolve_collision_for_read_with_bound_check(right, el_hash, left, *module, el_type, false, true);
+        get_builder0();
+        llvm::AllocaInst *res = builder0.CreateAlloca(llvm::Type::getInt1Ty(context), nullptr);
+        llvm_utils->create_if_else(builder->CreateICmpEQ(
+            capacity, llvm::ConstantInt::get(llvm::Type::getInt32Ty(context), llvm::APInt(32, 0))),
+        [&]() {
+            LLVM::CreateStore(*builder, llvm::ConstantInt::get(llvm::Type::getInt1Ty(context), llvm::APInt(1, 0)), res);
+        }, [&]() {
+            llvm::Value *el_hash = llvm_utils->set_api->get_el_hash(capacity, left, el_type, *module);
+            LLVM::CreateStore(*builder, llvm_utils->set_api->resolve_collision_for_read_with_bound_check(right, el_hash, left, *module, el_type, false, true), res);
+        });
+        tmp = LLVM::CreateLoad(*builder, res);
     }
 
     void visit_DictLen(const ASR::DictLen_t& x) {