r300/compiler: Add a register rename pass.

This pass renames register in order to make it easier for the pair
scheduler to group TEX instructions together.

This fixes fdo bug #28606

src/mesa/drivers/dri/r300/compiler/Makefile

@@ -23,6 +23,7 @@ C_SOURCES = \
 		radeon_dataflow_deadcode.c \
 		radeon_dataflow_swizzles.c \
 		radeon_optimize.c \
+		radeon_rename_regs.c \
 		r3xx_fragprog.c \
 		r300_fragprog.c \
 		r300_fragprog_swizzle.c \

src/mesa/drivers/dri/r300/compiler/SConscript

@@ -22,6 +22,7 @@ r300compiler = env.ConvenienceLibrary(
         'radeon_pair_schedule.c',
         'radeon_pair_regalloc.c',
         'radeon_optimize.c',
+        'radeon_rename_regs.c',
         'radeon_emulate_branches.c',
         'radeon_emulate_loops.c',
         'radeon_dataflow.c',

src/mesa/drivers/dri/r300/compiler/r3xx_fragprog.c

@@ -29,6 +29,7 @@
 #include "radeon_emulate_loops.h"
 #include "radeon_program_alu.h"
 #include "radeon_program_tex.h"
+#include "radeon_rename_regs.h"
 #include "r300_fragprog.h"
 #include "r300_fragprog_swizzle.h"
 #include "r500_fragprog.h"
@@ -179,6 +180,16 @@ void r3xx_compile_fragment_program(struct r300_fragment_program_compiler* c)
 
 	debug_program_log(c, "after dataflow passes");
 
+	if(!c->Base.is_r500) {
+		/* This pass makes it easier for the scheduler to group TEX
+		 * instructions and reduces the chances of creating too
+		 * many texture indirections.*/
+		rc_rename_regs(&c->Base);
+		if (c->Base.Error)
+			return;
+		debug_program_log(c, "after register rename");
+	}
+
 	rc_pair_translate(c);
 	if (c->Base.Error)
 		return;

src/mesa/drivers/dri/r300/compiler/radeon_rename_regs.c

@@ -0,0 +1,131 @@
+/*
+ * Copyright 2010 Tom Stellard <tstellar@gmail.com>
+ *
+ * All Rights Reserved.
+ *
+ * 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 COPYRIGHT OWNER(S) AND/OR ITS 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.
+ *
+ */
+
+/**
+ * \file
+ */
+
+#include "radeon_rename_regs.h"
+
+#include "radeon_compiler.h"
+#include "radeon_dataflow.h"
+
+struct reg_rename {
+	int old_index;
+	int new_index;
+	int temp_index;
+};
+
+static void rename_reg(void * data, struct rc_instruction * inst,
+			rc_register_file * file, unsigned int * index)
+{
+	struct reg_rename *r = data;
+
+	if(r->old_index == *index && *file == RC_FILE_TEMPORARY) {
+		*index = r->new_index;
+	}
+	else if(r->new_index == *index && *file == RC_FILE_TEMPORARY) {
+		*index = r->temp_index;
+	}
+}
+
+static void rename_all(
+	struct radeon_compiler *c,
+	struct rc_instruction * start,
+	unsigned int old,
+	unsigned int new,
+	unsigned int temp)
+{
+	struct rc_instruction * inst;
+	struct reg_rename r;
+	r.old_index = old;
+	r.new_index = new;
+	r.temp_index = temp;
+	for(inst = start; inst != &c->Program.Instructions;
+						inst = inst->Next) {
+		rc_remap_registers(inst, rename_reg, &r);
+	}
+}
+
+/**
+ * This function renames registers in an attempt to get the code close to
+ * SSA form.  After this function has completed, most of the register are only
+ * written to one time, with a few exceptions.  For example, this block of code
+ * will not be modified by this function:
+ * Mov Temp[0].x Const[0].x
+ * Mov Temp[0].y Const[0].y
+ * Basically, destination registers will be renamed if:
+ * 1. There have been no previous writes to that register
+ * or
+ * 2. If the instruction is writting to the exact components (no more, no less)
+ * of a register that has been written to by previous instructions.
+ *
+ * This function assumes all the instructions are still of type
+ * RC_INSTRUCTION_NORMAL.
+ */
+void rc_rename_regs(struct radeon_compiler * c)
+{
+	unsigned int cur_index = 0;
+	unsigned int icount;
+	struct rc_instruction * inst;
+	unsigned int * masks;
+
+	/* The number of instructions in the program is also the maximum
+	 * number of temp registers that could potentially be used. */
+	icount = rc_recompute_ips(c);
+	masks = memory_pool_malloc(&c->Pool, icount * sizeof(unsigned int));
+	memset(masks, 0, icount * sizeof(unsigned int));
+
+	for(inst = c->Program.Instructions.Next;
+					inst != &c->Program.Instructions;
+					inst = inst->Next) {
+		const struct rc_opcode_info * info;
+		if(inst->Type != RC_INSTRUCTION_NORMAL) {
+			rc_error(c, "%s only works with normal instructions.",
+								__FUNCTION__);
+			return;
+		}
+		unsigned int old_index, temp_index;
+		struct rc_dst_register * dst = &inst->U.I.DstReg;
+		info = rc_get_opcode_info(inst->U.I.Opcode);
+		if(!info->HasDstReg || dst->File != RC_FILE_TEMPORARY) {
+			continue;
+		}
+		if(dst->Index >= icount || !masks[dst->Index] ||
+					masks[dst->Index] == dst->WriteMask) {
+			old_index = dst->Index;
+			/* We need to set dst->Index here so get free temporary
+			 * will work. */
+			dst->Index = cur_index++;
+			temp_index = rc_find_free_temporary(c);
+			rename_all(c, inst->Next, old_index,
+						dst->Index, temp_index);
+		}
+		assert(dst->Index < icount);
+		masks[dst->Index] |= dst->WriteMask;
+	}
+}

src/mesa/drivers/dri/r300/compiler/radeon_rename_regs.h

@@ -0,0 +1,9 @@
+
+#ifndef RADEON_RENAME_REGS_H
+#define RADEON_RENAME_REGS_H
+
+struct radeon_compiler;
+
+void rc_rename_regs(struct radeon_compiler * c);
+
+#endif /* RADEON_RENAME_REGS_H */