src/compiler/nir/tests/opt_if_tests.cpp - third_party/mesa - Git at Google

 /*
  * Copyright © 2020 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  */

 #include "nir_test.h"

 class nir_opt_if_test : public nir_test {
 protected:
    nir_opt_if_test();

    nir_builder bld;

    nir_def *in_def;
    nir_variable *out_var;
 };

 nir_opt_if_test::nir_opt_if_test()
    : nir_test::nir_test("nir_opt_if_test")
 {
    nir_variable *var = nir_variable_create(b->shader, nir_var_shader_in, glsl_int_type(), "in");
    in_def = nir_load_var(b, var);

    out_var = nir_variable_create(b->shader, nir_var_shader_out, glsl_int_type(), "out");
 }

 TEST_F(nir_opt_if_test, opt_if_simplification)
 {
    /* Tests that opt_if_simplification correctly optimizes a simple case:
     *
     * vec1 1 ssa_2 = ieq ssa_0, ssa_1
     * if ssa_2 {
     *    block block_2:
     * } else {
     *    block block_3:
     *    do_work()
     * }
     */

    nir_def *one = nir_imm_int(b, 1);

    nir_def *cmp_result = nir_ieq(b, in_def, one);
    nir_if *nif = nir_push_if(b, cmp_result);

    nir_push_else(b, NULL);

    // do_work
    nir_store_var(b, out_var, one, 1);

    nir_pop_if(b, NULL);

    ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));

    nir_validate_shader(b->shader, NULL);

    ASSERT_TRUE(!exec_list_is_empty((&nir_if_first_then_block(nif)->instr_list)));
    ASSERT_TRUE(exec_list_is_empty((&nir_if_first_else_block(nif)->instr_list)));
 }

 TEST_F(nir_opt_if_test, opt_if_simplification_single_source_phi_after_if)
 {
    /* Tests that opt_if_simplification correctly handles single-source
     * phis after the if.
     *
     * vec1 1 ssa_2 = ieq ssa_0, ssa_1
     * if ssa_2 {
     *    block block_2:
     * } else {
     *    block block_3:
     *    do_work()
     *    return
     * }
     * block block_4:
     * vec1 32 ssa_3 = phi block_2: ssa_0
     */

    nir_def *one = nir_imm_int(b, 1);

    nir_def *cmp_result = nir_ieq(b, in_def, one);
    nir_if *nif = nir_push_if(b, cmp_result);

    nir_push_else(b, NULL);

    // do_work
    nir_store_var(b, out_var, one, 1);

    nir_jump_instr *jump = nir_jump_instr_create(b->shader, nir_jump_return);
    nir_builder_instr_insert(b, &jump->instr);

    nir_pop_if(b, NULL);

    nir_block *then_block = nir_if_last_then_block(nif);

    nir_phi_instr *const phi = nir_phi_instr_create(b->shader);

    nir_phi_instr_add_src(phi, then_block, one);

    nir_def_init(&phi->instr, &phi->def,
                 one->num_components, one->bit_size);

    nir_builder_instr_insert(b, &phi->instr);

    ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));

    nir_validate_shader(b->shader, NULL);

    ASSERT_TRUE(nir_block_ends_in_jump(nir_if_last_then_block(nif)));
    ASSERT_TRUE(exec_list_is_empty((&nir_if_first_else_block(nif)->instr_list)));
 }

 TEST_F(nir_opt_if_test, opt_if_alu_of_phi_progress)
 {
    nir_def *two = nir_imm_int(b, 2);
    nir_def *x = nir_imm_int(b, 0);

    nir_phi_instr *phi = nir_phi_instr_create(b->shader);

    nir_loop *loop = nir_push_loop(b);
    {
       nir_def_init(&phi->instr, &phi->def,
                    x->num_components, x->bit_size);

       nir_phi_instr_add_src(phi, x->parent_instr->block, x);

       nir_def *y = nir_iadd(b, &phi->def, two);
       nir_store_var(b, out_var,
                     nir_imul(b, &phi->def, two), 1);

       nir_phi_instr_add_src(phi, nir_cursor_current_block(b->cursor), y);
    }
    nir_pop_loop(b, loop);

    b->cursor = nir_before_block(nir_loop_first_block(loop));
    nir_builder_instr_insert(b, &phi->instr);

    nir_validate_shader(b->shader, "input");

    bool progress;

    int progress_count = 0;
    for (int i = 0; i < 10; i++) {
       progress = nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false);
       if (progress)
          progress_count++;
       else
          break;
       nir_opt_constant_folding(b->shader);
    }

    EXPECT_LE(progress_count, 2);
    ASSERT_FALSE(progress);
 }

 static const struct nir_opt_if_merge_test_config {
    template <class ParamType>
    std::string
    operator()(const ::testing::TestParamInfo<ParamType> &info) const
    {
       return info.param.name;
    }

    const char *name;

    /* Test parameter: Location of a return statement within the control flow */
    enum return_location {
       NO_RETURN,
       RETURN_IN_1ST_THEN,
       RETURN_IN_1ST_ELSE,
       RETURN_IN_2ND_THEN,
       RETURN_IN_2ND_ELSE,
    } return_location;
 } nir_opt_if_merge_test_configs [] = {
    { "no_return",          nir_opt_if_merge_test_config::NO_RETURN, },
    { "return_in_1st_then", nir_opt_if_merge_test_config::RETURN_IN_1ST_THEN, },
    { "return_in_1st_else", nir_opt_if_merge_test_config::RETURN_IN_1ST_ELSE, },
    { "return_in_2nd_then", nir_opt_if_merge_test_config::RETURN_IN_2ND_THEN, },
    { "return_in_2nd_else", nir_opt_if_merge_test_config::RETURN_IN_2ND_ELSE, },
 };

 class nir_opt_if_merge_test
    : public nir_opt_if_test
    , public ::testing::WithParamInterface<struct nir_opt_if_merge_test_config>
 {
 protected:
    virtual void SetUp();

    enum nir_opt_if_merge_test_config::return_location return_location;
 };

 void
 nir_opt_if_merge_test::SetUp()
 {
    struct nir_opt_if_merge_test_config config = GetParam();
    return_location = config.return_location;
 }

 INSTANTIATE_TEST_SUITE_P(
    nir_opt_if, nir_opt_if_merge_test,
    ::testing::ValuesIn(nir_opt_if_merge_test_configs),
    nir_opt_if_merge_test_config()
 );

 TEST_P(nir_opt_if_merge_test, opt_if_merge)
 {
    /* Tests that opt_if_merge correctly merges if statements with the same
     * condition, parameterized on the location of a return statement added
     * within the control-flow.
     *
     * block b0:   // preds:
     * 32     %0 = deref_var &in (shader_in int)
     * 32     %1 = @load_deref (%0) (access=none)
     * 32     %2 = load_const (0x00000001)
     * 32     %3 = load_const (0x00000002)
     * 32     %4 = load_const (0x00000006)
     * 1      %5 = ige %1, %2 (0x1)
     *             // succs: b1 b2
     * if %5 {
     *     block b1:   // preds: b0
     *     32     %6 = iadd %1, %2 (0x1)
     *     32     %7 = deref_var &out (shader_out int)
     *                 @store_deref (%7, %6) (wrmask=x, access=none)
     *                 // succs: b3
     * } else {
     *     block b2:   // preds: b0
     *     32     %8 = iadd %1, %3 (0x2)
     *     32     %9 = deref_var &out (shader_out int)
     *                 @store_deref (%9, %8) (wrmask=x, access=none)
     *                 // succs: b3
     * }
     * block b3:  // preds: b1 b2, succs: b4 b5
     * if %5 {
     *     block b4:   // preds: b3
     *     32    %10 = imul %1, %3 (0x2)
     *                 // succs: b6
     * } else {
     *     block b5:   // preds: b3
     *     32    %11 = imul %1, %4 (0x6)
     *                 // succs: b6
     * }
     * block b6:   // preds: b4 b5
     * 32    %12 = phi b4: %10, b5: %11
     * 32    %13 = deref_var &out (shader_out int)
     *             @store_deref (%13, %12) (wrmask=x, access=none)
     *             // succs: b7
     * block b7:
     */

    int instr_in_1st_then = 3, instr_in_1st_else = 3;
    int instr_in_2nd_then = 1, instr_in_2nd_else = 1;

    nir_def *one = nir_imm_int(b, 1);
    nir_def *two = nir_imm_int(b, 2);
    nir_def *six = nir_imm_int(b, 6);

    nir_def *cmp_result = nir_ige(b, in_def, one);

    nir_if *nif = nir_push_if(b, cmp_result);

    nir_store_var(b, out_var, nir_iadd(b, in_def, one), 1);
    if (return_location == nir_opt_if_merge_test_config::RETURN_IN_1ST_THEN) {
       nir_jump(b, nir_jump_return);
       instr_in_1st_then++;
    }

    nir_push_else(b, NULL);

    nir_store_var(b, out_var, nir_iadd(b, in_def, two), 1);
    if (return_location == nir_opt_if_merge_test_config::RETURN_IN_1ST_ELSE) {
       nir_jump(b, nir_jump_return);
       instr_in_1st_else++;
    }

    nir_pop_if(b, NULL);

    nir_phi_instr *phi = nir_phi_instr_create(b->shader);
    nir_def_init(&phi->instr, &phi->def,
                 one->num_components, one->bit_size);

    nir_if *next_if = nir_push_if(b, cmp_result);

    nir_def *y1 = nir_imul(b, in_def, two);
    if (return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_THEN) {
       nir_jump(b, nir_jump_return);
       instr_in_2nd_then++;
    } else {
       nir_phi_instr_add_src(phi, nir_cursor_current_block(b->cursor), y1);
    }

    nir_push_else(b, NULL);

    nir_def *y2 = nir_imul(b, in_def, six);
    if (return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_ELSE) {
       nir_jump(b, nir_jump_return);
       instr_in_2nd_else++;
    } else {
       nir_phi_instr_add_src(phi, nir_cursor_current_block(b->cursor), y2);
    }

    nir_pop_if(b, NULL);

    nir_builder_instr_insert(b, &phi->instr);

    // do_work
    nir_store_var(b, out_var, &phi->def, 1);

    if (return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_THEN ||
        return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_ELSE) {
       ASSERT_FALSE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));
    } else if (return_location == nir_opt_if_merge_test_config::NO_RETURN) {
       ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));
       instr_in_1st_then += instr_in_2nd_then;
       instr_in_1st_else += instr_in_2nd_else;
       instr_in_2nd_then = 0;
       instr_in_2nd_else = 0;
    } else {
       ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));
    }

    nir_validate_shader(b->shader, NULL);

    ASSERT_EQ(exec_list_length((&nir_if_first_then_block(nif)->instr_list)), instr_in_1st_then);
    ASSERT_EQ(exec_list_length((&nir_if_first_else_block(nif)->instr_list)), instr_in_1st_else);
    ASSERT_EQ(exec_list_length((&nir_if_first_then_block(next_if)->instr_list)), instr_in_2nd_then);
    ASSERT_EQ(exec_list_length((&nir_if_first_else_block(next_if)->instr_list)), instr_in_2nd_else);
 }
	/*
	* Copyright © 2020 Intel Corporation
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	* DEALINGS IN THE SOFTWARE.
	*/

	#include "nir_test.h"

	class nir_opt_if_test : public nir_test {
	protected:
	nir_opt_if_test();

	nir_builder bld;

	nir_def *in_def;
	nir_variable *out_var;
	};

	nir_opt_if_test::nir_opt_if_test()
	: nir_test::nir_test("nir_opt_if_test")
	{
	nir_variable *var = nir_variable_create(b->shader, nir_var_shader_in, glsl_int_type(), "in");
	in_def = nir_load_var(b, var);

	out_var = nir_variable_create(b->shader, nir_var_shader_out, glsl_int_type(), "out");
	}

	TEST_F(nir_opt_if_test, opt_if_simplification)
	{
	/* Tests that opt_if_simplification correctly optimizes a simple case:
	*
	* vec1 1 ssa_2 = ieq ssa_0, ssa_1
	* if ssa_2 {
	* block block_2:
	* } else {
	* block block_3:
	* do_work()
	* }
	*/

	nir_def *one = nir_imm_int(b, 1);

	nir_def *cmp_result = nir_ieq(b, in_def, one);
	nir_if *nif = nir_push_if(b, cmp_result);

	nir_push_else(b, NULL);

	// do_work
	nir_store_var(b, out_var, one, 1);

	nir_pop_if(b, NULL);

	ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));

	nir_validate_shader(b->shader, NULL);

	ASSERT_TRUE(!exec_list_is_empty((&nir_if_first_then_block(nif)->instr_list)));
	ASSERT_TRUE(exec_list_is_empty((&nir_if_first_else_block(nif)->instr_list)));
	}

	TEST_F(nir_opt_if_test, opt_if_simplification_single_source_phi_after_if)
	{
	/* Tests that opt_if_simplification correctly handles single-source
	* phis after the if.
	*
	* vec1 1 ssa_2 = ieq ssa_0, ssa_1
	* if ssa_2 {
	* block block_2:
	* } else {
	* block block_3:
	* do_work()
	* return
	* }
	* block block_4:
	* vec1 32 ssa_3 = phi block_2: ssa_0
	*/

	nir_def *one = nir_imm_int(b, 1);

	nir_def *cmp_result = nir_ieq(b, in_def, one);
	nir_if *nif = nir_push_if(b, cmp_result);

	nir_push_else(b, NULL);

	// do_work
	nir_store_var(b, out_var, one, 1);

	nir_jump_instr *jump = nir_jump_instr_create(b->shader, nir_jump_return);
	nir_builder_instr_insert(b, &jump->instr);

	nir_pop_if(b, NULL);

	nir_block *then_block = nir_if_last_then_block(nif);

	nir_phi_instr *const phi = nir_phi_instr_create(b->shader);

	nir_phi_instr_add_src(phi, then_block, one);

	nir_def_init(&phi->instr, &phi->def,
	one->num_components, one->bit_size);

	nir_builder_instr_insert(b, &phi->instr);

	ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));

	nir_validate_shader(b->shader, NULL);

	ASSERT_TRUE(nir_block_ends_in_jump(nir_if_last_then_block(nif)));
	ASSERT_TRUE(exec_list_is_empty((&nir_if_first_else_block(nif)->instr_list)));
	}

	TEST_F(nir_opt_if_test, opt_if_alu_of_phi_progress)
	{
	nir_def *two = nir_imm_int(b, 2);
	nir_def *x = nir_imm_int(b, 0);

	nir_phi_instr *phi = nir_phi_instr_create(b->shader);

	nir_loop *loop = nir_push_loop(b);
	{
	nir_def_init(&phi->instr, &phi->def,
	x->num_components, x->bit_size);

	nir_phi_instr_add_src(phi, x->parent_instr->block, x);

	nir_def *y = nir_iadd(b, &phi->def, two);
	nir_store_var(b, out_var,
	nir_imul(b, &phi->def, two), 1);

	nir_phi_instr_add_src(phi, nir_cursor_current_block(b->cursor), y);
	}
	nir_pop_loop(b, loop);

	b->cursor = nir_before_block(nir_loop_first_block(loop));
	nir_builder_instr_insert(b, &phi->instr);

	nir_validate_shader(b->shader, "input");

	bool progress;

	int progress_count = 0;
	for (int i = 0; i < 10; i++) {
	progress = nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false);
	if (progress)
	progress_count++;
	else
	break;
	nir_opt_constant_folding(b->shader);
	}

	EXPECT_LE(progress_count, 2);
	ASSERT_FALSE(progress);
	}

	static const struct nir_opt_if_merge_test_config {
	template <class ParamType>
	std::string
	operator()(const ::testing::TestParamInfo<ParamType> &info) const
	{
	return info.param.name;
	}

	const char *name;

	/* Test parameter: Location of a return statement within the control flow */
	enum return_location {
	NO_RETURN,
	RETURN_IN_1ST_THEN,
	RETURN_IN_1ST_ELSE,
	RETURN_IN_2ND_THEN,
	RETURN_IN_2ND_ELSE,
	} return_location;
	} nir_opt_if_merge_test_configs [] = {
	{ "no_return", nir_opt_if_merge_test_config::NO_RETURN, },
	{ "return_in_1st_then", nir_opt_if_merge_test_config::RETURN_IN_1ST_THEN, },
	{ "return_in_1st_else", nir_opt_if_merge_test_config::RETURN_IN_1ST_ELSE, },
	{ "return_in_2nd_then", nir_opt_if_merge_test_config::RETURN_IN_2ND_THEN, },
	{ "return_in_2nd_else", nir_opt_if_merge_test_config::RETURN_IN_2ND_ELSE, },
	};

	class nir_opt_if_merge_test
	: public nir_opt_if_test
	, public ::testing::WithParamInterface<struct nir_opt_if_merge_test_config>
	{
	protected:
	virtual void SetUp();

	enum nir_opt_if_merge_test_config::return_location return_location;
	};

	void
	nir_opt_if_merge_test::SetUp()
	{
	struct nir_opt_if_merge_test_config config = GetParam();
	return_location = config.return_location;
	}

	INSTANTIATE_TEST_SUITE_P(
	nir_opt_if, nir_opt_if_merge_test,
	::testing::ValuesIn(nir_opt_if_merge_test_configs),
	nir_opt_if_merge_test_config()
	);

	TEST_P(nir_opt_if_merge_test, opt_if_merge)
	{
	/* Tests that opt_if_merge correctly merges if statements with the same
	* condition, parameterized on the location of a return statement added
	* within the control-flow.
	*
	* block b0: // preds:
	* 32 %0 = deref_var &in (shader_in int)
	* 32 %1 = @load_deref (%0) (access=none)
	* 32 %2 = load_const (0x00000001)
	* 32 %3 = load_const (0x00000002)
	* 32 %4 = load_const (0x00000006)
	* 1 %5 = ige %1, %2 (0x1)
	* // succs: b1 b2
	* if %5 {
	* block b1: // preds: b0
	* 32 %6 = iadd %1, %2 (0x1)
	* 32 %7 = deref_var &out (shader_out int)
	* @store_deref (%7, %6) (wrmask=x, access=none)
	* // succs: b3
	* } else {
	* block b2: // preds: b0
	* 32 %8 = iadd %1, %3 (0x2)
	* 32 %9 = deref_var &out (shader_out int)
	* @store_deref (%9, %8) (wrmask=x, access=none)
	* // succs: b3
	* }
	* block b3: // preds: b1 b2, succs: b4 b5
	* if %5 {
	* block b4: // preds: b3
	* 32 %10 = imul %1, %3 (0x2)
	* // succs: b6
	* } else {
	* block b5: // preds: b3
	* 32 %11 = imul %1, %4 (0x6)
	* // succs: b6
	* }
	* block b6: // preds: b4 b5
	* 32 %12 = phi b4: %10, b5: %11
	* 32 %13 = deref_var &out (shader_out int)
	* @store_deref (%13, %12) (wrmask=x, access=none)
	* // succs: b7
	* block b7:
	*/

	int instr_in_1st_then = 3, instr_in_1st_else = 3;
	int instr_in_2nd_then = 1, instr_in_2nd_else = 1;

	nir_def *one = nir_imm_int(b, 1);
	nir_def *two = nir_imm_int(b, 2);
	nir_def *six = nir_imm_int(b, 6);

	nir_def *cmp_result = nir_ige(b, in_def, one);

	nir_if *nif = nir_push_if(b, cmp_result);

	nir_store_var(b, out_var, nir_iadd(b, in_def, one), 1);
	if (return_location == nir_opt_if_merge_test_config::RETURN_IN_1ST_THEN) {
	nir_jump(b, nir_jump_return);
	instr_in_1st_then++;
	}

	nir_push_else(b, NULL);

	nir_store_var(b, out_var, nir_iadd(b, in_def, two), 1);
	if (return_location == nir_opt_if_merge_test_config::RETURN_IN_1ST_ELSE) {
	nir_jump(b, nir_jump_return);
	instr_in_1st_else++;
	}

	nir_pop_if(b, NULL);

	nir_phi_instr *phi = nir_phi_instr_create(b->shader);
	nir_def_init(&phi->instr, &phi->def,
	one->num_components, one->bit_size);

	nir_if *next_if = nir_push_if(b, cmp_result);

	nir_def *y1 = nir_imul(b, in_def, two);
	if (return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_THEN) {
	nir_jump(b, nir_jump_return);
	instr_in_2nd_then++;
	} else {
	nir_phi_instr_add_src(phi, nir_cursor_current_block(b->cursor), y1);
	}

	nir_push_else(b, NULL);

	nir_def *y2 = nir_imul(b, in_def, six);
	if (return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_ELSE) {
	nir_jump(b, nir_jump_return);
	instr_in_2nd_else++;
	} else {
	nir_phi_instr_add_src(phi, nir_cursor_current_block(b->cursor), y2);
	}

	nir_pop_if(b, NULL);

	nir_builder_instr_insert(b, &phi->instr);

	// do_work
	nir_store_var(b, out_var, &phi->def, 1);

	if (return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_THEN \|\|
	return_location == nir_opt_if_merge_test_config::RETURN_IN_2ND_ELSE) {
	ASSERT_FALSE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));
	} else if (return_location == nir_opt_if_merge_test_config::NO_RETURN) {
	ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));
	instr_in_1st_then += instr_in_2nd_then;
	instr_in_1st_else += instr_in_2nd_else;
	instr_in_2nd_then = 0;
	instr_in_2nd_else = 0;
	} else {
	ASSERT_TRUE(nir_opt_if(b->shader, nir_opt_if_optimize_phi_true_false));
	}

	nir_validate_shader(b->shader, NULL);

	ASSERT_EQ(exec_list_length((&nir_if_first_then_block(nif)->instr_list)), instr_in_1st_then);
	ASSERT_EQ(exec_list_length((&nir_if_first_else_block(nif)->instr_list)), instr_in_1st_else);
	ASSERT_EQ(exec_list_length((&nir_if_first_then_block(next_if)->instr_list)), instr_in_2nd_then);
	ASSERT_EQ(exec_list_length((&nir_if_first_else_block(next_if)->instr_list)), instr_in_2nd_else);
	}