r300g/compiler: Fix bug in OMOD folding

The OMOD value was only being folded to one instruction in cases where
the MUL instruction was reading a value written by more than one
instruction.

NOTE: This is a candidate for the stable branches.

Reviewed-by: Marek Olšák <maraeo@gmail.com>
(cherry picked from commit 10bcc843f8898c2466b610d08edc27516e10cc51)

3 files changed, 77 insertions, 1 deletions

diff --git a/src/gallium/drivers/r300/Makefile.am b/src/gallium/drivers/r300/Makefile.am
index 020134985b..c98dbfa22d 100644
--- a/src/gallium/drivers/r300/Makefile.am
+++ b/src/gallium/drivers/r300/Makefile.am
@@ -29,6 +29,7 @@ r300_compiler_tests_CPPFLAGS = \
 	-I$(top_srcdir)/src/gallium/drivers/r300/compiler
 r300_compiler_tests_SOURCES = \
 	$(testdir)/r300_compiler_tests.c \
+	$(testdir)/radeon_compiler_optimize_tests.c \
 	$(testdir)/radeon_compiler_util_tests.c \
 	$(testdir)/rc_test_helpers.c \
 	$(testdir)/unit_test.c
diff --git a/src/gallium/drivers/r300/compiler/radeon_optimize.c b/src/gallium/drivers/r300/compiler/radeon_optimize.c
index 0714d79418..734c7f2348 100644
--- a/src/gallium/drivers/r300/compiler/radeon_optimize.c
+++ b/src/gallium/drivers/r300/compiler/radeon_optimize.c
@@ -816,7 +816,7 @@ static int peephole_mul_omod(
 
 	/* Rewrite the instructions */
 	for (var = writer_list->Item; var; var = var->Friend) {
-		struct rc_variable * writer = writer_list->Item;
+		struct rc_variable * writer = var;
 		unsigned conversion_swizzle = rc_make_conversion_swizzle(
 					writer->Inst->U.I.DstReg.WriteMask,
 					inst_mul->U.I.DstReg.WriteMask);
diff --git a/src/gallium/drivers/r300/compiler/tests/radeon_compiler_optimize_tests.c b/src/gallium/drivers/r300/compiler/tests/radeon_compiler_optimize_tests.c
new file mode 100644
index 0000000000..600228e83b
--- /dev/null
+++ b/src/gallium/drivers/r300/compiler/tests/radeon_compiler_optimize_tests.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2013 Advanced Micro Devices, Inc.
+ *
+ * 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
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHOR(S) AND/OR THEIR SUPPLIERS 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.
+ *
+ * Author: Tom Stellard <thomas.stellard@amd.com>
+ */
+
+#include "radeon_compiler.h"
+#include "radeon_dataflow.h"
+
+#include "r300_compiler_tests.h"
+#include "rc_test_helpers.h"
+#include "unit_test.h"
+
+static void test_runner_rc_optimize(struct test_result * result)
+{
+	struct radeon_compiler c;
+	struct rc_instruction *inst;
+	struct rc_instruction *inst_list[3];
+	unsigned inst_count = 0;
+	float const0[4] = {2.0f, 0.0f, 0.0f, 0.0f};
+	unsigned pass = 1;
+
+	test_begin(result);
+	init_compiler(&c, RC_FRAGMENT_PROGRAM, 1, 0);
+
+	rc_constants_add_immediate_vec4(&c.Program.Constants, const0);
+
+	add_instruction(&c, "RCP temp[0].x, const[1].x___;");
+	add_instruction(&c, "RCP temp[0].y, const[1]._y__;");
+	add_instruction(&c, "MUL temp[1].xy, const[0].xx__, temp[0].xy__;");
+	add_instruction(&c, "MOV output[0].xy, temp[1].xy;" );
+
+	rc_optimize(&c, NULL);
+
+	for(inst = c.Program.Instructions.Next;
+					inst != &c.Program.Instructions;
+					inst = inst->Next, inst_count++) {
+		inst_list[inst_count] = inst;
+	}
+
+	if (inst_list[0]->U.I.Omod != RC_OMOD_MUL_2 ||
+			inst_list[1]->U.I.Omod != RC_OMOD_MUL_2 ||
+			inst_list[2]->U.I.Opcode != RC_OPCODE_MOV) {
+		pass = 0;
+	}
+	test_check(result, pass);
+}
+
+unsigned radeon_compiler_optimize_run_tests()
+{
+	struct test tests[] = {
+		{"rc_optimize() => peephole_mul_omod()", test_runner_rc_optimize},
+		{NULL, NULL}
+	};
+	return run_tests(tests);
+}