nir: Add tests for copy propagation of derefs

Also tests for removal of redundant loads, that we currently handle as
part of the copy propagation.

Note some tests involve multiple blocks and are currently DISABLED
because they (expectedly) fail.

v2: Add missing DISABLED prefix to "multi block" tests. (Jason)

Reviewed-by: Jason Ekstrand <[email protected]>

1 files changed, 300 insertions, 0 deletions

diff --git a/src/compiler/nir/tests/vars_tests.cpp b/src/compiler/nir/tests/vars_tests.cpp
index eee3ad9ca52..d06f41d02e9 100644
--- a/src/compiler/nir/tests/vars_tests.cpp
+++ b/src/compiler/nir/tests/vars_tests.cpp
@@ -131,11 +131,131 @@ nir_vars_test::find_next_intrinsic(nir_intrinsic_op intrinsic,
 }
 
 /* Allow grouping the tests while still sharing the helpers. */
+class nir_redundant_load_vars_test : public nir_vars_test {};
 class nir_copy_prop_vars_test : public nir_vars_test {};
 class nir_dead_write_vars_test : public nir_vars_test {};
 
 } // namespace
 
+TEST_F(nir_redundant_load_vars_test, duplicated_load)
+{
+   /* Load a variable twice in the same block.  One should be removed. */
+
+   nir_variable *in = create_int(nir_var_shader_in, "in");
+   nir_variable **out = create_many_int(nir_var_shader_out, "out", 2);
+
+   nir_store_var(b, out[0], nir_load_var(b, in), 1);
+   nir_store_var(b, out[1], nir_load_var(b, in), 1);
+
+   nir_validate_shader(b->shader);
+
+   ASSERT_EQ(count_intrinsics(nir_intrinsic_load_deref), 2);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   EXPECT_TRUE(progress);
+
+   nir_validate_shader(b->shader);
+
+   ASSERT_EQ(count_intrinsics(nir_intrinsic_load_deref), 1);
+}
+
+TEST_F(nir_redundant_load_vars_test, DISABLED_duplicated_load_in_two_blocks)
+{
+   /* Load a variable twice in different blocks.  One should be removed. */
+
+   nir_variable *in = create_int(nir_var_shader_in, "in");
+   nir_variable **out = create_many_int(nir_var_shader_out, "out", 2);
+
+   nir_store_var(b, out[0], nir_load_var(b, in), 1);
+
+   /* Forces the stores to be in different blocks. */
+   nir_pop_if(b, nir_push_if(b, nir_imm_int(b, 0)));
+
+   nir_store_var(b, out[1], nir_load_var(b, in), 1);
+
+   nir_validate_shader(b->shader);
+
+   ASSERT_EQ(count_intrinsics(nir_intrinsic_load_deref), 2);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   EXPECT_TRUE(progress);
+
+   nir_validate_shader(b->shader);
+
+   ASSERT_EQ(count_intrinsics(nir_intrinsic_load_deref), 1);
+}
+
+TEST_F(nir_redundant_load_vars_test, DISABLED_invalidate_inside_if_block)
+{
+   /* Load variables, then write to some of then in different branches of the
+    * if statement.  They should be invalidated accordingly.
+    */
+
+   nir_variable **g = create_many_int(nir_var_global, "g", 3);
+   nir_variable **out = create_many_int(nir_var_shader_out, "out", 3);
+
+   nir_load_var(b, g[0]);
+   nir_load_var(b, g[1]);
+   nir_load_var(b, g[2]);
+
+   nir_if *if_stmt = nir_push_if(b, nir_imm_int(b, 0));
+   nir_store_var(b, g[0], nir_imm_int(b, 10), 1);
+
+   nir_push_else(b, if_stmt);
+   nir_store_var(b, g[1], nir_imm_int(b, 20), 1);
+
+   nir_pop_if(b, if_stmt);
+
+   nir_store_var(b, out[0], nir_load_var(b, g[0]), 1);
+   nir_store_var(b, out[1], nir_load_var(b, g[1]), 1);
+   nir_store_var(b, out[2], nir_load_var(b, g[2]), 1);
+
+   nir_validate_shader(b->shader);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   EXPECT_TRUE(progress);
+
+   /* There are 3 initial loads, plus 2 loads for the values invalidated
+    * inside the if statement.
+    */
+   ASSERT_EQ(count_intrinsics(nir_intrinsic_load_deref), 5);
+
+   /* We only load g[2] once. */
+   unsigned g2_load_count = 0;
+   nir_intrinsic_instr *load = NULL;
+   for (int i = 0; i < 5; i++) {
+      load = find_next_intrinsic(nir_intrinsic_load_deref, load);
+      if (nir_intrinsic_get_var(load, 0) == g[2])
+         g2_load_count++;
+   }
+   EXPECT_EQ(g2_load_count, 1);
+}
+
+TEST_F(nir_redundant_load_vars_test, invalidate_live_load_in_the_end_of_loop)
+{
+   /* Invalidating a load in the end of loop body will apply to the whole loop
+    * body.
+    */
+
+   nir_variable *v = create_int(nir_var_shader_storage, "v");
+
+   nir_load_var(b, v);
+
+   nir_loop *loop = nir_push_loop(b);
+
+   nir_if *if_stmt = nir_push_if(b, nir_imm_int(b, 0));
+   nir_jump(b, nir_jump_break);
+   nir_pop_if(b, if_stmt);
+
+   nir_load_var(b, v);
+   nir_store_var(b, v, nir_imm_int(b, 10), 1);
+
+   nir_pop_loop(b, loop);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   ASSERT_FALSE(progress);
+}
+
 TEST_F(nir_copy_prop_vars_test, simple_copies)
 {
    nir_variable *in   = create_int(nir_var_shader_in,  "in");
@@ -190,6 +310,186 @@ TEST_F(nir_copy_prop_vars_test, simple_store_load)
    }
 }
 
+TEST_F(nir_copy_prop_vars_test, store_store_load)
+{
+   nir_variable **v = create_many_ivec2(nir_var_local, "v", 2);
+   unsigned mask = 1 | 2;
+
+   nir_ssa_def *first_value = nir_imm_ivec2(b, 10, 20);
+   nir_store_var(b, v[0], first_value, mask);
+
+   nir_ssa_def *second_value = nir_imm_ivec2(b, 30, 40);
+   nir_store_var(b, v[0], second_value, mask);
+
+   nir_ssa_def *read_value = nir_load_var(b, v[0]);
+   nir_store_var(b, v[1], read_value, mask);
+
+   nir_validate_shader(b->shader);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   EXPECT_TRUE(progress);
+
+   nir_validate_shader(b->shader);
+
+   /* Store to v[1] should use second_value directly. */
+   nir_intrinsic_instr *store_to_v1 = NULL;
+   while ((store_to_v1 = find_next_intrinsic(nir_intrinsic_store_deref, store_to_v1)) != NULL) {
+      if (nir_intrinsic_get_var(store_to_v1, 0) == v[1]) {
+         ASSERT_TRUE(store_to_v1->src[1].is_ssa);
+         EXPECT_EQ(store_to_v1->src[1].ssa, second_value);
+         break;
+      }
+   }
+   EXPECT_TRUE(store_to_v1);
+}
+
+TEST_F(nir_copy_prop_vars_test, store_store_load_different_components)
+{
+   nir_variable **v = create_many_ivec2(nir_var_local, "v", 2);
+
+   nir_ssa_def *first_value = nir_imm_ivec2(b, 10, 20);
+   nir_store_var(b, v[0], first_value, 1 << 1);
+
+   nir_ssa_def *second_value = nir_imm_ivec2(b, 30, 40);
+   nir_store_var(b, v[0], second_value, 1 << 0);
+
+   nir_ssa_def *read_value = nir_load_var(b, v[0]);
+   nir_store_var(b, v[1], read_value, 1 << 1);
+
+   nir_validate_shader(b->shader);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   EXPECT_TRUE(progress);
+
+   nir_validate_shader(b->shader);
+
+   nir_opt_constant_folding(b->shader);
+   nir_validate_shader(b->shader);
+
+   /* Store to v[1] should use first_value directly.  The write of
+    * second_value did not overwrite the component it uses.
+    */
+   nir_intrinsic_instr *store_to_v1 = NULL;
+   while ((store_to_v1 = find_next_intrinsic(nir_intrinsic_store_deref, store_to_v1)) != NULL) {
+      if (nir_intrinsic_get_var(store_to_v1, 0) == v[1]) {
+         ASSERT_TRUE(store_to_v1->src[1].is_ssa);
+
+         nir_const_value *const_index = nir_src_as_const_value(store_to_v1->src[1]);
+         ASSERT_TRUE(const_index);
+         ASSERT_EQ(const_index->u32[1], 20);
+         break;
+      }
+   }
+   EXPECT_TRUE(store_to_v1);
+}
+
+TEST_F(nir_copy_prop_vars_test, DISABLED_store_store_load_different_components_in_many_blocks)
+{
+   nir_variable **v = create_many_ivec2(nir_var_local, "v", 2);
+
+   nir_ssa_def *first_value = nir_imm_ivec2(b, 10, 20);
+   nir_store_var(b, v[0], first_value, 1 << 1);
+
+   /* Adding an if statement will cause blocks to be created. */
+   nir_pop_if(b, nir_push_if(b, nir_imm_int(b, 0)));
+
+   nir_ssa_def *second_value = nir_imm_ivec2(b, 30, 40);
+   nir_store_var(b, v[0], second_value, 1 << 0);
+
+   /* Adding an if statement will cause blocks to be created. */
+   nir_pop_if(b, nir_push_if(b, nir_imm_int(b, 0)));
+
+   nir_ssa_def *read_value = nir_load_var(b, v[0]);
+   nir_store_var(b, v[1], read_value, 1 << 1);
+
+   nir_validate_shader(b->shader);
+
+   nir_print_shader(b->shader, stdout);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   EXPECT_TRUE(progress);
+
+   nir_print_shader(b->shader, stdout);
+
+   nir_validate_shader(b->shader);
+
+   nir_opt_constant_folding(b->shader);
+   nir_validate_shader(b->shader);
+
+   /* Store to v[1] should use first_value directly.  The write of
+    * second_value did not overwrite the component it uses.
+    */
+   nir_intrinsic_instr *store_to_v1 = NULL;
+   while ((store_to_v1 = find_next_intrinsic(nir_intrinsic_store_deref, store_to_v1)) != NULL) {
+      if (nir_intrinsic_get_var(store_to_v1, 0) == v[1]) {
+         ASSERT_TRUE(store_to_v1->src[1].is_ssa);
+
+         nir_const_value *const_index = nir_src_as_const_value(store_to_v1->src[1]);
+         ASSERT_TRUE(const_index);
+         ASSERT_EQ(const_index->u32[1], 20);
+         break;
+      }
+   }
+   EXPECT_TRUE(store_to_v1);
+}
+
+TEST_F(nir_copy_prop_vars_test, DISABLED_memory_barrier_in_two_blocks)
+{
+   nir_variable **v = create_many_int(nir_var_shader_storage, "v", 4);
+
+   nir_store_var(b, v[0], nir_imm_int(b, 1), 1);
+   nir_store_var(b, v[1], nir_imm_int(b, 2), 1);
+
+   /* Split into many blocks. */
+   nir_pop_if(b, nir_push_if(b, nir_imm_int(b, 0)));
+
+   nir_store_var(b, v[2], nir_load_var(b, v[0]), 1);
+
+   nir_builder_instr_insert(b, &nir_intrinsic_instr_create(b->shader, nir_intrinsic_memory_barrier)->instr);
+
+   nir_store_var(b, v[3], nir_load_var(b, v[1]), 1);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   ASSERT_TRUE(progress);
+
+   /* Only the second load will remain after the optimization. */
+   ASSERT_EQ(1, count_intrinsics(nir_intrinsic_load_deref));
+   nir_intrinsic_instr *load = NULL;
+   load = find_next_intrinsic(nir_intrinsic_load_deref, load);
+   ASSERT_EQ(nir_intrinsic_get_var(load, 0), v[1]);
+}
+
+TEST_F(nir_copy_prop_vars_test, DISABLED_simple_store_load_in_two_blocks)
+{
+   nir_variable **v = create_many_ivec2(nir_var_local, "v", 2);
+   unsigned mask = 1 | 2;
+
+   nir_ssa_def *stored_value = nir_imm_ivec2(b, 10, 20);
+   nir_store_var(b, v[0], stored_value, mask);
+
+   /* Adding an if statement will cause blocks to be created. */
+   nir_pop_if(b, nir_push_if(b, nir_imm_int(b, 0)));
+
+   nir_ssa_def *read_value = nir_load_var(b, v[0]);
+   nir_store_var(b, v[1], read_value, mask);
+
+   nir_validate_shader(b->shader);
+
+   bool progress = nir_opt_copy_prop_vars(b->shader);
+   EXPECT_TRUE(progress);
+
+   nir_validate_shader(b->shader);
+
+   ASSERT_EQ(count_intrinsics(nir_intrinsic_store_deref), 2);
+
+   nir_intrinsic_instr *store = NULL;
+   for (int i = 0; i < 2; i++) {
+      store = find_next_intrinsic(nir_intrinsic_store_deref, store);
+      ASSERT_TRUE(store->src[1].is_ssa);
+      EXPECT_EQ(store->src[1].ssa, stored_value);
+   }
+}
+
 TEST_F(nir_dead_write_vars_test, no_dead_writes_in_block)
 {
    nir_variable **v = create_many_int(nir_var_shader_storage, "v", 2);