r300/compiler/radeon_program_alu.c

/*
 * Copyright (C) 2008 Nicolai Haehnle.
 *
 * 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
 *
 * Shareable transformations that transform "special" ALU instructions
 * into ALU instructions that are supported by hardware.
 *
 */

#include "radeon_program_alu.h"

#include "radeon_compiler.h"
#include "radeon_compiler_util.h"


static struct rc_instruction *emit1(
	struct radeon_compiler * c, struct rc_instruction * after,
	rc_opcode Opcode, struct rc_sub_instruction * base,
	struct rc_dst_register DstReg, struct rc_src_register SrcReg)
{
	struct rc_instruction *fpi = rc_insert_new_instruction(c, after);

	if (base) {
		memcpy(&fpi->U.I, base, sizeof(struct rc_sub_instruction));
	}

	fpi->U.I.Opcode = Opcode;
	fpi->U.I.DstReg = DstReg;
	fpi->U.I.SrcReg[0] = SrcReg;
	return fpi;
}

static struct rc_instruction *emit2(
	struct radeon_compiler * c, struct rc_instruction * after,
	rc_opcode Opcode, struct rc_sub_instruction * base,
	struct rc_dst_register DstReg,
	struct rc_src_register SrcReg0, struct rc_src_register SrcReg1)
{
	struct rc_instruction *fpi = rc_insert_new_instruction(c, after);

	if (base) {
		memcpy(&fpi->U.I, base, sizeof(struct rc_sub_instruction));
	}

	fpi->U.I.Opcode = Opcode;
	fpi->U.I.DstReg = DstReg;
	fpi->U.I.SrcReg[0] = SrcReg0;
	fpi->U.I.SrcReg[1] = SrcReg1;
	return fpi;
}

static struct rc_instruction *emit3(
	struct radeon_compiler * c, struct rc_instruction * after,
	rc_opcode Opcode, struct rc_sub_instruction * base,
	struct rc_dst_register DstReg,
	struct rc_src_register SrcReg0, struct rc_src_register SrcReg1,
	struct rc_src_register SrcReg2)
{
	struct rc_instruction *fpi = rc_insert_new_instruction(c, after);

	if (base) {
		memcpy(&fpi->U.I, base, sizeof(struct rc_sub_instruction));
	}

	fpi->U.I.Opcode = Opcode;
	fpi->U.I.DstReg = DstReg;
	fpi->U.I.SrcReg[0] = SrcReg0;
	fpi->U.I.SrcReg[1] = SrcReg1;
	fpi->U.I.SrcReg[2] = SrcReg2;
	return fpi;
}

static struct rc_dst_register dstregtmpmask(int index, int mask)
{
	struct rc_dst_register dst = {0, 0, 0};
	dst.File = RC_FILE_TEMPORARY;
	dst.Index = index;
	dst.WriteMask = mask;
	return dst;
}

static const struct rc_src_register builtin_zero = {
	.File = RC_FILE_NONE,
	.Index = 0,
	.Swizzle = RC_SWIZZLE_0000
};
static const struct rc_src_register builtin_one = {
	.File = RC_FILE_NONE,
	.Index = 0,
	.Swizzle = RC_SWIZZLE_1111
};

static const struct rc_src_register builtin_half = {
	.File = RC_FILE_NONE,
	.Index = 0,
	.Swizzle = RC_SWIZZLE_HHHH
};

static const struct rc_src_register srcreg_undefined = {
	.File = RC_FILE_NONE,
	.Index = 0,
	.Swizzle = RC_SWIZZLE_XYZW
};

static struct rc_src_register srcreg(int file, int index)
{
	struct rc_src_register src = srcreg_undefined;
	src.File = file;
	src.Index = index;
	return src;
}

static struct rc_src_register srcregswz(int file, int index, int swz)
{
	struct rc_src_register src = srcreg_undefined;
	src.File = file;
	src.Index = index;
	src.Swizzle = swz;
	return src;
}

static struct rc_src_register absolute(struct rc_src_register reg)
{
	struct rc_src_register newreg = reg;
	newreg.Abs = 1;
	newreg.Negate = RC_MASK_NONE;
	return newreg;
}

static struct rc_src_register negate(struct rc_src_register reg)
{
	struct rc_src_register newreg = reg;
	newreg.Negate = newreg.Negate ^ RC_MASK_XYZW;
	return newreg;
}

static struct rc_src_register swizzle(struct rc_src_register reg,
		rc_swizzle x, rc_swizzle y, rc_swizzle z, rc_swizzle w)
{
	struct rc_src_register swizzled = reg;
	swizzled.Swizzle = combine_swizzles4(reg.Swizzle, x, y, z, w);
	return swizzled;
}

static struct rc_src_register swizzle_smear(struct rc_src_register reg,
		rc_swizzle x)
{
	return swizzle(reg, x, x, x, x);
}

static struct rc_src_register swizzle_xxxx(struct rc_src_register reg)
{
	return swizzle_smear(reg, RC_SWIZZLE_X);
}

static struct rc_src_register swizzle_yyyy(struct rc_src_register reg)
{
	return swizzle_smear(reg, RC_SWIZZLE_Y);
}

static struct rc_src_register swizzle_zzzz(struct rc_src_register reg)
{
	return swizzle_smear(reg, RC_SWIZZLE_Z);
}

static struct rc_src_register swizzle_wwww(struct rc_src_register reg)
{
	return swizzle_smear(reg, RC_SWIZZLE_W);
}

static int is_dst_safe_to_reuse(struct rc_instruction *inst)
{
	const struct rc_opcode_info *info = rc_get_opcode_info(inst->U.I.Opcode);
	unsigned i;

	assert(info->HasDstReg);

	if (inst->U.I.DstReg.File != RC_FILE_TEMPORARY)
		return 0;

	for (i = 0; i < info->NumSrcRegs; i++) {
		if (inst->U.I.SrcReg[i].File == RC_FILE_TEMPORARY &&
		    inst->U.I.SrcReg[i].Index == inst->U.I.DstReg.Index)
			return 0;
	}

	return 1;
}

static struct rc_dst_register try_to_reuse_dst(struct radeon_compiler *c,
					       struct rc_instruction *inst)
{
	unsigned tmp;

	if (is_dst_safe_to_reuse(inst))
		tmp = inst->U.I.DstReg.Index;
	else
		tmp = rc_find_free_temporary(c);

	return dstregtmpmask(tmp, inst->U.I.DstReg.WriteMask);
}

static void transform_CEIL(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	/* Assuming:
	 *     ceil(x) = -floor(-x)
	 *
	 * After inlining floor:
	 *     ceil(x) = -(-x-frac(-x))
	 *
	 * After simplification:
	 *     ceil(x) = x+frac(-x)
	 */

	struct rc_dst_register dst = try_to_reuse_dst(c, inst);
	emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dst, negate(inst->U.I.SrcReg[0]));
	emit2(c, inst->Prev, RC_OPCODE_ADD, &inst->U.I, inst->U.I.DstReg,
		inst->U.I.SrcReg[0], srcreg(RC_FILE_TEMPORARY, dst.Index));
	rc_remove_instruction(inst);
}

static void transform_DP2(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_src_register src0 = inst->U.I.SrcReg[0];
	struct rc_src_register src1 = inst->U.I.SrcReg[1];
	src0.Negate &= ~(RC_MASK_Z | RC_MASK_W);
	src0.Swizzle &= ~(63 << (3 * 2));
	src0.Swizzle |= (RC_SWIZZLE_ZERO << (3 * 2)) | (RC_SWIZZLE_ZERO << (3 * 3));
	src1.Negate &= ~(RC_MASK_Z | RC_MASK_W);
	src1.Swizzle &= ~(63 << (3 * 2));
	src1.Swizzle |= (RC_SWIZZLE_ZERO << (3 * 2)) | (RC_SWIZZLE_ZERO << (3 * 3));
	emit2(c, inst->Prev, RC_OPCODE_DP3, &inst->U.I, inst->U.I.DstReg, src0, src1);
	rc_remove_instruction(inst);
}

/**
 * [1, src0.y*src1.y, src0.z, src1.w]
 * So basically MUL with lotsa swizzling.
 */
static void transform_DST(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	emit2(c, inst->Prev, RC_OPCODE_MUL, &inst->U.I, inst->U.I.DstReg,
		swizzle(inst->U.I.SrcReg[0], RC_SWIZZLE_ONE, RC_SWIZZLE_Y, RC_SWIZZLE_Z, RC_SWIZZLE_ONE),
		swizzle(inst->U.I.SrcReg[1], RC_SWIZZLE_ONE, RC_SWIZZLE_Y, RC_SWIZZLE_ONE, RC_SWIZZLE_W));
	rc_remove_instruction(inst);
}

static void transform_FLR(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);
	emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dst, inst->U.I.SrcReg[0]);
	emit2(c, inst->Prev, RC_OPCODE_ADD, &inst->U.I, inst->U.I.DstReg,
		inst->U.I.SrcReg[0], negate(srcreg(RC_FILE_TEMPORARY, dst.Index)));
	rc_remove_instruction(inst);
}

static void transform_TRUNC(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	/* Definition of trunc:
	 *   trunc(x) = (abs(x) - fract(abs(x))) * sgn(x)
	 *
	 * The multiplication by sgn(x) can be simplified using CMP:
	 *   y * sgn(x) = (x < 0 ? -y : y)
	 */
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);
	emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dst, absolute(inst->U.I.SrcReg[0]));
	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, absolute(inst->U.I.SrcReg[0]),
	      negate(srcreg(RC_FILE_TEMPORARY, dst.Index)));
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg, inst->U.I.SrcReg[0],
	      negate(srcreg(RC_FILE_TEMPORARY, dst.Index)), srcreg(RC_FILE_TEMPORARY, dst.Index));
	rc_remove_instruction(inst);
}

/**
 * Definition of LIT (from ARB_fragment_program):
 *
 *  tmp = VectorLoad(op0);
 *  if (tmp.x < 0) tmp.x = 0;
 *  if (tmp.y < 0) tmp.y = 0;
 *  if (tmp.w < -(128.0-epsilon)) tmp.w = -(128.0-epsilon);
 *  else if (tmp.w > 128-epsilon) tmp.w = 128-epsilon;
 *  result.x = 1.0;
 *  result.y = tmp.x;
 *  result.z = (tmp.x > 0) ? RoughApproxPower(tmp.y, tmp.w) : 0.0;
 *  result.w = 1.0;
 *
 * The longest path of computation is the one leading to result.z,
 * consisting of 5 operations. This implementation of LIT takes
 * 5 slots, if the subsequent optimization passes are clever enough
 * to pair instructions correctly.
 */
static void transform_LIT(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	unsigned int constant;
	unsigned int constant_swizzle;
	unsigned int temp;
	struct rc_src_register srctemp;

	constant = rc_constants_add_immediate_scalar(&c->Program.Constants, -127.999999, &constant_swizzle);

	if (inst->U.I.DstReg.WriteMask != RC_MASK_XYZW || inst->U.I.DstReg.File != RC_FILE_TEMPORARY) {
		struct rc_instruction * inst_mov;

		inst_mov = emit1(c, inst,
			RC_OPCODE_MOV, NULL, inst->U.I.DstReg,
			srcreg(RC_FILE_TEMPORARY, rc_find_free_temporary(c)));

		inst->U.I.DstReg.File = RC_FILE_TEMPORARY;
		inst->U.I.DstReg.Index = inst_mov->U.I.SrcReg[0].Index;
		inst->U.I.DstReg.WriteMask = RC_MASK_XYZW;
	}

	temp = inst->U.I.DstReg.Index;
	srctemp = srcreg(RC_FILE_TEMPORARY, temp);

	/* tmp.x = max(0.0, Src.x); */
	/* tmp.y = max(0.0, Src.y); */
	/* tmp.w = clamp(Src.z, -128+eps, 128-eps); */
	emit2(c, inst->Prev, RC_OPCODE_MAX, NULL,
		dstregtmpmask(temp, RC_MASK_XYW),
		inst->U.I.SrcReg[0],
		swizzle(srcreg(RC_FILE_CONSTANT, constant),
			RC_SWIZZLE_ZERO, RC_SWIZZLE_ZERO, RC_SWIZZLE_ZERO, constant_swizzle&3));
	emit2(c, inst->Prev, RC_OPCODE_MIN, NULL,
		dstregtmpmask(temp, RC_MASK_Z),
		swizzle_wwww(srctemp),
		negate(srcregswz(RC_FILE_CONSTANT, constant, constant_swizzle)));

	/* tmp.w = Pow(tmp.y, tmp.w) */
	emit1(c, inst->Prev, RC_OPCODE_LG2, NULL,
		dstregtmpmask(temp, RC_MASK_W),
		swizzle_yyyy(srctemp));
	emit2(c, inst->Prev, RC_OPCODE_MUL, NULL,
		dstregtmpmask(temp, RC_MASK_W),
		swizzle_wwww(srctemp),
		swizzle_zzzz(srctemp));
	emit1(c, inst->Prev, RC_OPCODE_EX2, NULL,
		dstregtmpmask(temp, RC_MASK_W),
		swizzle_wwww(srctemp));

	/* tmp.z = (tmp.x > 0) ? tmp.w : 0.0 */
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I,
		dstregtmpmask(temp, RC_MASK_Z),
		negate(swizzle_xxxx(srctemp)),
		swizzle_wwww(srctemp),
		builtin_zero);

	/* tmp.x, tmp.y, tmp.w = 1.0, tmp.x, 1.0 */
	emit1(c, inst->Prev, RC_OPCODE_MOV, &inst->U.I,
		dstregtmpmask(temp, RC_MASK_XYW),
		swizzle(srctemp, RC_SWIZZLE_ONE, RC_SWIZZLE_X, RC_SWIZZLE_ONE, RC_SWIZZLE_ONE));

	rc_remove_instruction(inst);
}

static void transform_LRP(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	emit3(c, inst->Prev, RC_OPCODE_MAD, NULL,
		dst,
		negate(inst->U.I.SrcReg[0]), inst->U.I.SrcReg[2], inst->U.I.SrcReg[2]);
	emit3(c, inst->Prev, RC_OPCODE_MAD, &inst->U.I,
		inst->U.I.DstReg,
		inst->U.I.SrcReg[0], inst->U.I.SrcReg[1], srcreg(RC_FILE_TEMPORARY, dst.Index));

	rc_remove_instruction(inst);
}

static void transform_POW(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register tempdst = try_to_reuse_dst(c, inst);
	struct rc_src_register tempsrc = srcreg(RC_FILE_TEMPORARY, tempdst.Index);
	tempdst.WriteMask = RC_MASK_W;
	tempsrc.Swizzle = RC_SWIZZLE_WWWW;

	emit1(c, inst->Prev, RC_OPCODE_LG2, NULL, tempdst, swizzle_xxxx(inst->U.I.SrcReg[0]));
	emit2(c, inst->Prev, RC_OPCODE_MUL, NULL, tempdst, tempsrc, swizzle_xxxx(inst->U.I.SrcReg[1]));
	emit1(c, inst->Prev, RC_OPCODE_EX2, &inst->U.I, inst->U.I.DstReg, tempsrc);

	rc_remove_instruction(inst);
}

/* dst = ROUND(src) :
 *   add = src + .5
 *   frac = FRC(add)
 *   dst = add - frac
 *
 * According to the GLSL spec, the implementor can decide which way to round
 * when the fraction is .5.  We round down for .5.
 *
 */
static void transform_ROUND(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	unsigned int mask = inst->U.I.DstReg.WriteMask;
	unsigned int frac_index, add_index;
	struct rc_dst_register frac_dst, add_dst;
	struct rc_src_register frac_src, add_src;

	/* add = src + .5 */
	add_index = rc_find_free_temporary(c);
	add_dst = dstregtmpmask(add_index, mask);
	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, add_dst, inst->U.I.SrcReg[0],
								builtin_half);
	add_src = srcreg(RC_FILE_TEMPORARY, add_dst.Index);


	/* frac = FRC(add) */
	frac_index = rc_find_free_temporary(c);
	frac_dst = dstregtmpmask(frac_index, mask);
	emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, frac_dst, add_src);
	frac_src = srcreg(RC_FILE_TEMPORARY, frac_dst.Index);

	/* dst = add - frac */
	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, inst->U.I.DstReg,
						add_src, negate(frac_src));
	rc_remove_instruction(inst);
}

static void transform_RSQ(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	inst->U.I.SrcReg[0] = absolute(inst->U.I.SrcReg[0]);
}

static void transform_SEQ(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
		negate(absolute(srcreg(RC_FILE_TEMPORARY, dst.Index))), builtin_zero, builtin_one);

	rc_remove_instruction(inst);
}

static void transform_SGE(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
		srcreg(RC_FILE_TEMPORARY, dst.Index), builtin_zero, builtin_one);

	rc_remove_instruction(inst);
}

static void transform_SGT(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, negate(inst->U.I.SrcReg[0]), inst->U.I.SrcReg[1]);
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
		srcreg(RC_FILE_TEMPORARY, dst.Index), builtin_one, builtin_zero);

	rc_remove_instruction(inst);
}

static void transform_SLE(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, negate(inst->U.I.SrcReg[0]), inst->U.I.SrcReg[1]);
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
		srcreg(RC_FILE_TEMPORARY, dst.Index), builtin_zero, builtin_one);

	rc_remove_instruction(inst);
}

static void transform_SLT(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
		srcreg(RC_FILE_TEMPORARY, dst.Index), builtin_one, builtin_zero);

	rc_remove_instruction(inst);
}

static void transform_SNE(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL, dst, inst->U.I.SrcReg[0], negate(inst->U.I.SrcReg[1]));
	emit3(c, inst->Prev, RC_OPCODE_CMP, &inst->U.I, inst->U.I.DstReg,
		negate(absolute(srcreg(RC_FILE_TEMPORARY, dst.Index))), builtin_one, builtin_zero);

	rc_remove_instruction(inst);
}

static void transform_SSG(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	/* result = sign(x)
	 *
	 *   CMP tmp0, -x, 1, 0
	 *   CMP tmp1, x, 1, 0
	 *   ADD result, tmp0, -tmp1;
	 */
	struct rc_dst_register dst0;
	unsigned tmp1;

	/* 0 < x */
	dst0 = try_to_reuse_dst(c, inst);
	emit3(c, inst->Prev, RC_OPCODE_CMP, NULL,
	      dst0,
	      negate(inst->U.I.SrcReg[0]),
	      builtin_one,
	      builtin_zero);

	/* x < 0 */
	tmp1 = rc_find_free_temporary(c);
	emit3(c, inst->Prev, RC_OPCODE_CMP, NULL,
	      dstregtmpmask(tmp1, inst->U.I.DstReg.WriteMask),
	      inst->U.I.SrcReg[0],
	      builtin_one,
	      builtin_zero);

	/* Either both are zero, or one of them is one and the other is zero. */
	/* result = tmp0 - tmp1 */
	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL,
	      inst->U.I.DstReg,
	      srcreg(RC_FILE_TEMPORARY, dst0.Index),
	      negate(srcreg(RC_FILE_TEMPORARY, tmp1)));

	rc_remove_instruction(inst);
}

static void transform_SUB(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	inst->U.I.Opcode = RC_OPCODE_ADD;
	inst->U.I.SrcReg[1] = negate(inst->U.I.SrcReg[1]);
}

/**
 * Can be used as a transformation for @ref radeonClauseLocalTransform,
 * no userData necessary.
 *
 * Eliminates the following ALU instructions:
 *  CEIL, DST, FLR, LIT, LRP, POW, SEQ, SGE, SGT, SLE, SLT, SNE, SUB
 * using:
 *  MOV, ADD, MUL, MAD, FRC, DP3, LG2, EX2, CMP
 *
 * Transforms RSQ to Radeon's native RSQ by explicitly setting
 * absolute value.
 *
 * @note should be applicable to R300 and R500 fragment programs.
 */
int radeonTransformALU(
	struct radeon_compiler * c,
	struct rc_instruction* inst,
	void* unused)
{
	switch(inst->U.I.Opcode) {
	case RC_OPCODE_CEIL: transform_CEIL(c, inst); return 1;
	case RC_OPCODE_DP2: transform_DP2(c, inst); return 1;
	case RC_OPCODE_DST: transform_DST(c, inst); return 1;
	case RC_OPCODE_FLR: transform_FLR(c, inst); return 1;
	case RC_OPCODE_LIT: transform_LIT(c, inst); return 1;
	case RC_OPCODE_LRP: transform_LRP(c, inst); return 1;
	case RC_OPCODE_POW: transform_POW(c, inst); return 1;
	case RC_OPCODE_ROUND: transform_ROUND(c, inst); return 1;
	case RC_OPCODE_RSQ: transform_RSQ(c, inst); return 1;
	case RC_OPCODE_SEQ: transform_SEQ(c, inst); return 1;
	case RC_OPCODE_SGE: transform_SGE(c, inst); return 1;
	case RC_OPCODE_SGT: transform_SGT(c, inst); return 1;
	case RC_OPCODE_SLE: transform_SLE(c, inst); return 1;
	case RC_OPCODE_SLT: transform_SLT(c, inst); return 1;
	case RC_OPCODE_SNE: transform_SNE(c, inst); return 1;
	case RC_OPCODE_SSG: transform_SSG(c, inst); return 1;
	case RC_OPCODE_SUB: transform_SUB(c, inst); return 1;
	case RC_OPCODE_TRUNC: transform_TRUNC(c, inst); return 1;
	default:
		return 0;
	}
}

static void transform_r300_vertex_CMP(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	/* There is no decent CMP available, so let's rig one up.
	 * CMP is defined as dst = src0 < 0.0 ? src1 : src2
	 * The following sequence consumes zero to two temps and two extra slots
	 * (the second temp and the second slot is consumed by transform_LRP),
	 * but should be equivalent:
	 *
	 * SLT tmp0, src0, 0.0
	 * LRP dst, tmp0, src1, src2
	 *
	 * Yes, I know, I'm a mad scientist. ~ C. & M. */
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);

	/* SLT tmp0, src0, 0.0 */
	emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
		dst,
		inst->U.I.SrcReg[0], builtin_zero);

	/* LRP dst, tmp0, src1, src2 */
	transform_LRP(c,
		emit3(c, inst->Prev, RC_OPCODE_LRP, NULL,
		      inst->U.I.DstReg,
		      srcreg(RC_FILE_TEMPORARY, dst.Index), inst->U.I.SrcReg[1],  inst->U.I.SrcReg[2]));

	rc_remove_instruction(inst);
}

static void transform_r300_vertex_DP2(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_instruction *next_inst = inst->Next;
	transform_DP2(c, inst);
	next_inst->Prev->U.I.Opcode = RC_OPCODE_DP4;
}

static void transform_r300_vertex_DP3(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_src_register src0 = inst->U.I.SrcReg[0];
	struct rc_src_register src1 = inst->U.I.SrcReg[1];
	src0.Negate &= ~RC_MASK_W;
	src0.Swizzle &= ~(7 << (3 * 3));
	src0.Swizzle |= RC_SWIZZLE_ZERO << (3 * 3);
	src1.Negate &= ~RC_MASK_W;
	src1.Swizzle &= ~(7 << (3 * 3));
	src1.Swizzle |= RC_SWIZZLE_ZERO << (3 * 3);
	emit2(c, inst->Prev, RC_OPCODE_DP4, &inst->U.I, inst->U.I.DstReg, src0, src1);
	rc_remove_instruction(inst);
}

static void transform_r300_vertex_fix_LIT(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_dst_register dst = try_to_reuse_dst(c, inst);
	unsigned constant_swizzle;
	int constant = rc_constants_add_immediate_scalar(&c->Program.Constants,
							 0.0000000000000000001,
							 &constant_swizzle);

	/* MOV dst, src */
	dst.WriteMask = RC_MASK_XYZW;
	emit1(c, inst->Prev, RC_OPCODE_MOV, NULL,
		dst,
		inst->U.I.SrcReg[0]);

	/* MAX dst.y, src, 0.00...001 */
	emit2(c, inst->Prev, RC_OPCODE_MAX, NULL,
		dstregtmpmask(dst.Index, RC_MASK_Y),
		srcreg(RC_FILE_TEMPORARY, dst.Index),
		srcregswz(RC_FILE_CONSTANT, constant, constant_swizzle));

	inst->U.I.SrcReg[0] = srcreg(RC_FILE_TEMPORARY, dst.Index);
}

static void transform_r300_vertex_SEQ(struct radeon_compiler *c,
	struct rc_instruction *inst)
{
	/* x = y  <==>  x >= y && y >= x */
	int tmp = rc_find_free_temporary(c);

	/* x <= y */
	emit2(c, inst->Prev, RC_OPCODE_SGE, NULL,
	      dstregtmpmask(tmp, inst->U.I.DstReg.WriteMask),
	      inst->U.I.SrcReg[0],
	      inst->U.I.SrcReg[1]);

	/* y <= x */
	emit2(c, inst->Prev, RC_OPCODE_SGE, NULL,
	      inst->U.I.DstReg,
	      inst->U.I.SrcReg[1],
	      inst->U.I.SrcReg[0]);

	/* x && y  =  x * y */
	emit2(c, inst->Prev, RC_OPCODE_MUL, NULL,
	      inst->U.I.DstReg,
	      srcreg(RC_FILE_TEMPORARY, tmp),
	      srcreg(inst->U.I.DstReg.File, inst->U.I.DstReg.Index));

	rc_remove_instruction(inst);
}

static void transform_r300_vertex_SNE(struct radeon_compiler *c,
	struct rc_instruction *inst)
{
	/* x != y  <==>  x < y || y < x */
	int tmp = rc_find_free_temporary(c);

	/* x < y */
	emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
	      dstregtmpmask(tmp, inst->U.I.DstReg.WriteMask),
	      inst->U.I.SrcReg[0],
	      inst->U.I.SrcReg[1]);

	/* y < x */
	emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
	      inst->U.I.DstReg,
	      inst->U.I.SrcReg[1],
	      inst->U.I.SrcReg[0]);

	/* x || y  =  max(x, y) */
	emit2(c, inst->Prev, RC_OPCODE_MAX, NULL,
	      inst->U.I.DstReg,
	      srcreg(RC_FILE_TEMPORARY, tmp),
	      srcreg(inst->U.I.DstReg.File, inst->U.I.DstReg.Index));

	rc_remove_instruction(inst);
}

static void transform_r300_vertex_SGT(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	/* x > y  <==>  -x < -y */
	inst->U.I.Opcode = RC_OPCODE_SLT;
	inst->U.I.SrcReg[0].Negate ^= RC_MASK_XYZW;
	inst->U.I.SrcReg[1].Negate ^= RC_MASK_XYZW;
}

static void transform_r300_vertex_SLE(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	/* x <= y  <==>  -x >= -y */
	inst->U.I.Opcode = RC_OPCODE_SGE;
	inst->U.I.SrcReg[0].Negate ^= RC_MASK_XYZW;
	inst->U.I.SrcReg[1].Negate ^= RC_MASK_XYZW;
}

static void transform_r300_vertex_SSG(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	/* result = sign(x)
	 *
	 *   SLT tmp0, 0, x;
	 *   SLT tmp1, x, 0;
	 *   ADD result, tmp0, -tmp1;
	 */
	struct rc_dst_register dst0;
	unsigned tmp1;

	/* 0 < x */
	dst0 = try_to_reuse_dst(c, inst);
	emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
	      dst0,
	      builtin_zero,
	      inst->U.I.SrcReg[0]);

	/* x < 0 */
	tmp1 = rc_find_free_temporary(c);
	emit2(c, inst->Prev, RC_OPCODE_SLT, NULL,
	      dstregtmpmask(tmp1, inst->U.I.DstReg.WriteMask),
	      inst->U.I.SrcReg[0],
	      builtin_zero);

	/* Either both are zero, or one of them is one and the other is zero. */
	/* result = tmp0 - tmp1 */
	emit2(c, inst->Prev, RC_OPCODE_ADD, NULL,
	      inst->U.I.DstReg,
	      srcreg(RC_FILE_TEMPORARY, dst0.Index),
	      negate(srcreg(RC_FILE_TEMPORARY, tmp1)));

	rc_remove_instruction(inst);
}

static void transform_vertex_TRUNC(struct radeon_compiler* c,
	struct rc_instruction* inst)
{
	struct rc_instruction *next = inst->Next;

	/* next->Prev is removed after each transformation and replaced
	 * by a new instruction. */
	transform_TRUNC(c, next->Prev);
	transform_r300_vertex_CMP(c, next->Prev);
}

/**
 * For use with rc_local_transform, this transforms non-native ALU
 * instructions of the r300 up to r500 vertex engine.
 */
int r300_transform_vertex_alu(
	struct radeon_compiler * c,
	struct rc_instruction* inst,
	void* unused)
{
	switch(inst->U.I.Opcode) {
	case RC_OPCODE_CEIL: transform_CEIL(c, inst); return 1;
	case RC_OPCODE_CMP: transform_r300_vertex_CMP(c, inst); return 1;
	case RC_OPCODE_DP2: transform_r300_vertex_DP2(c, inst); return 1;
	case RC_OPCODE_DP3: transform_r300_vertex_DP3(c, inst); return 1;
	case RC_OPCODE_FLR: transform_FLR(c, inst); return 1;
	case RC_OPCODE_LIT: transform_r300_vertex_fix_LIT(c, inst); return 1;
	case RC_OPCODE_LRP: transform_LRP(c, inst); return 1;
	case RC_OPCODE_SEQ:
		if (!c->is_r500) {
			transform_r300_vertex_SEQ(c, inst);
			return 1;
		}
		return 0;
	case RC_OPCODE_SGT: transform_r300_vertex_SGT(c, inst); return 1;
	case RC_OPCODE_SLE: transform_r300_vertex_SLE(c, inst); return 1;
	case RC_OPCODE_SNE:
		if (!c->is_r500) {
			transform_r300_vertex_SNE(c, inst);
			return 1;
		}
		return 0;
	case RC_OPCODE_SSG: transform_r300_vertex_SSG(c, inst); return 1;
	case RC_OPCODE_SUB: transform_SUB(c, inst); return 1;
	case RC_OPCODE_TRUNC: transform_vertex_TRUNC(c, inst); return 1;
	default:
		return 0;
	}
}

static void sincos_constants(struct radeon_compiler* c, unsigned int *constants)
{
	static const float SinCosConsts[2][4] = {
		{
			1.273239545,		/* 4/PI */
			-0.405284735,		/* -4/(PI*PI) */
			3.141592654,		/* PI */
			0.2225			/* weight */
		},
		{
			0.75,
			0.5,
			0.159154943,		/* 1/(2*PI) */
			6.283185307		/* 2*PI */
		}
	};
	int i;

	for(i = 0; i < 2; ++i)
		constants[i] = rc_constants_add_immediate_vec4(&c->Program.Constants, SinCosConsts[i]);
}

/**
 * Approximate sin(x), where x is clamped to (-pi/2, pi/2).
 *
 * MUL tmp.xy, src, { 4/PI, -4/(PI^2) }
 * MAD tmp.x, tmp.y, |src|, tmp.x
 * MAD tmp.y, tmp.x, |tmp.x|, -tmp.x
 * MAD dest, tmp.y, weight, tmp.x
 */
static void sin_approx(
	struct radeon_compiler* c, struct rc_instruction * inst,
	struct rc_dst_register dst, struct rc_src_register src, const unsigned int* constants)
{
	unsigned int tempreg = rc_find_free_temporary(c);

	emit2(c, inst->Prev, RC_OPCODE_MUL, NULL, dstregtmpmask(tempreg, RC_MASK_XY),
		swizzle_xxxx(src),
		srcreg(RC_FILE_CONSTANT, constants[0]));
	emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_X),
		swizzle_yyyy(srcreg(RC_FILE_TEMPORARY, tempreg)),
		absolute(swizzle_xxxx(src)),
		swizzle_xxxx(srcreg(RC_FILE_TEMPORARY, tempreg)));
	emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_Y),
		swizzle_xxxx(srcreg(RC_FILE_TEMPORARY, tempreg)),
		absolute(swizzle_xxxx(srcreg(RC_FILE_TEMPORARY, tempreg))),
		negate(swizzle_xxxx(srcreg(RC_FILE_TEMPORARY, tempreg))));
	emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dst,
		swizzle_yyyy(srcreg(RC_FILE_TEMPORARY, tempreg)),
		swizzle_wwww(srcreg(RC_FILE_CONSTANT, constants[0])),
		swizzle_xxxx(srcreg(RC_FILE_TEMPORARY, tempreg)));
}

/**
 * Translate the trigonometric functions COS and SIN
 * using only the basic instructions
 *  MOV, ADD, MUL, MAD, FRC
 */
int r300_transform_trig_simple(struct radeon_compiler* c,
	struct rc_instruction* inst,
	void* unused)
{
	unsigned int constants[2];
	unsigned int tempreg;

	if (inst->U.I.Opcode != RC_OPCODE_COS &&
	    inst->U.I.Opcode != RC_OPCODE_SIN)
		return 0;

	tempreg = rc_find_free_temporary(c);

	sincos_constants(c, constants);

	if (inst->U.I.Opcode == RC_OPCODE_COS) {
		/* MAD tmp.x, src, 1/(2*PI), 0.75 */
		/* FRC tmp.x, tmp.x */
		/* MAD tmp.z, tmp.x, 2*PI, -PI */
		emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_W),
			swizzle_xxxx(inst->U.I.SrcReg[0]),
			swizzle_zzzz(srcreg(RC_FILE_CONSTANT, constants[1])),
			swizzle_xxxx(srcreg(RC_FILE_CONSTANT, constants[1])));
		emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dstregtmpmask(tempreg, RC_MASK_W),
			swizzle_wwww(srcreg(RC_FILE_TEMPORARY, tempreg)));
		emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_W),
			swizzle_wwww(srcreg(RC_FILE_TEMPORARY, tempreg)),
			swizzle_wwww(srcreg(RC_FILE_CONSTANT, constants[1])),
			negate(swizzle_zzzz(srcreg(RC_FILE_CONSTANT, constants[0]))));

		sin_approx(c, inst, inst->U.I.DstReg,
			swizzle_wwww(srcreg(RC_FILE_TEMPORARY, tempreg)),
			constants);
	} else if (inst->U.I.Opcode == RC_OPCODE_SIN) {
		emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_W),
			swizzle_xxxx(inst->U.I.SrcReg[0]),
			swizzle_zzzz(srcreg(RC_FILE_CONSTANT, constants[1])),
			swizzle_yyyy(srcreg(RC_FILE_CONSTANT, constants[1])));
		emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dstregtmpmask(tempreg, RC_MASK_W),
			swizzle_wwww(srcreg(RC_FILE_TEMPORARY, tempreg)));
		emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_W),
			swizzle_wwww(srcreg(RC_FILE_TEMPORARY, tempreg)),
			swizzle_wwww(srcreg(RC_FILE_CONSTANT, constants[1])),
			negate(swizzle_zzzz(srcreg(RC_FILE_CONSTANT, constants[0]))));

		sin_approx(c, inst, inst->U.I.DstReg,
			swizzle_wwww(srcreg(RC_FILE_TEMPORARY, tempreg)),
			constants);
	} else {
		struct rc_dst_register dst;

		emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_XY),
			swizzle_xxxx(inst->U.I.SrcReg[0]),
			swizzle_zzzz(srcreg(RC_FILE_CONSTANT, constants[1])),
			swizzle(srcreg(RC_FILE_CONSTANT, constants[1]), RC_SWIZZLE_X, RC_SWIZZLE_Y, RC_SWIZZLE_Z, RC_SWIZZLE_W));
		emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dstregtmpmask(tempreg, RC_MASK_XY),
			srcreg(RC_FILE_TEMPORARY, tempreg));
		emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(tempreg, RC_MASK_XY),
			srcreg(RC_FILE_TEMPORARY, tempreg),
			swizzle_wwww(srcreg(RC_FILE_CONSTANT, constants[1])),
			negate(swizzle_zzzz(srcreg(RC_FILE_CONSTANT, constants[0]))));

		dst = inst->U.I.DstReg;

		dst.WriteMask = inst->U.I.DstReg.WriteMask & RC_MASK_X;
		sin_approx(c, inst, dst,
			swizzle_xxxx(srcreg(RC_FILE_TEMPORARY, tempreg)),
			constants);

		dst.WriteMask = inst->U.I.DstReg.WriteMask & RC_MASK_Y;
		sin_approx(c, inst, dst,
			swizzle_yyyy(srcreg(RC_FILE_TEMPORARY, tempreg)),
			constants);
	}

	rc_remove_instruction(inst);

	return 1;
}

static void r300_transform_SIN_COS(struct radeon_compiler *c,
	struct rc_instruction *inst,
	unsigned srctmp)
{
	if (inst->U.I.Opcode == RC_OPCODE_COS) {
		emit1(c, inst->Prev, RC_OPCODE_COS, &inst->U.I, inst->U.I.DstReg,
			srcregswz(RC_FILE_TEMPORARY, srctmp, RC_SWIZZLE_WWWW));
	} else if (inst->U.I.Opcode == RC_OPCODE_SIN) {
		emit1(c, inst->Prev, RC_OPCODE_SIN, &inst->U.I,
			inst->U.I.DstReg, srcregswz(RC_FILE_TEMPORARY, srctmp, RC_SWIZZLE_WWWW));
	}

	rc_remove_instruction(inst);
}


/**
 * Transform the trigonometric functions COS and SIN
 * to include pre-scaling by 1/(2*PI) and taking the fractional
 * part, so that the input to COS and SIN is always in the range [0,1).
 *
 * @warning This transformation implicitly changes the semantics of SIN and COS!
 */
int radeonTransformTrigScale(struct radeon_compiler* c,
	struct rc_instruction* inst,
	void* unused)
{
	static const float RCP_2PI = 0.15915494309189535;
	unsigned int temp;
	unsigned int constant;
	unsigned int constant_swizzle;

	if (inst->U.I.Opcode != RC_OPCODE_COS &&
	    inst->U.I.Opcode != RC_OPCODE_SIN)
		return 0;

	if (!c->needs_trig_input_transform)
		return 1;

	temp = rc_find_free_temporary(c);
	constant = rc_constants_add_immediate_scalar(&c->Program.Constants, RCP_2PI, &constant_swizzle);

	emit2(c, inst->Prev, RC_OPCODE_MUL, NULL, dstregtmpmask(temp, RC_MASK_W),
		swizzle_xxxx(inst->U.I.SrcReg[0]),
		srcregswz(RC_FILE_CONSTANT, constant, constant_swizzle));
	emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dstregtmpmask(temp, RC_MASK_W),
		srcreg(RC_FILE_TEMPORARY, temp));

	r300_transform_SIN_COS(c, inst, temp);
	return 1;
}

/**
 * Transform the trigonometric functions COS and SIN
 * so that the input to COS and SIN is always in the range [-PI, PI].
 */
int r300_transform_trig_scale_vertex(struct radeon_compiler *c,
	struct rc_instruction *inst,
	void *unused)
{
	static const float cons[4] = {0.15915494309189535, 0.5, 6.28318530717959, -3.14159265358979};
	unsigned int temp;
	unsigned int constant;

	if (inst->U.I.Opcode != RC_OPCODE_COS &&
	    inst->U.I.Opcode != RC_OPCODE_SIN)
		return 0;

	if (!c->needs_trig_input_transform)
		return 1;

	/* Repeat x in the range [-PI, PI]:
	 *
	 *   repeat(x) = frac(x / 2PI + 0.5) * 2PI - PI
	 */

	temp = rc_find_free_temporary(c);
	constant = rc_constants_add_immediate_vec4(&c->Program.Constants, cons);

	emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(temp, RC_MASK_W),
		swizzle_xxxx(inst->U.I.SrcReg[0]),
		srcregswz(RC_FILE_CONSTANT, constant, RC_SWIZZLE_XXXX),
		srcregswz(RC_FILE_CONSTANT, constant, RC_SWIZZLE_YYYY));
	emit1(c, inst->Prev, RC_OPCODE_FRC, NULL, dstregtmpmask(temp, RC_MASK_W),
		srcreg(RC_FILE_TEMPORARY, temp));
	emit3(c, inst->Prev, RC_OPCODE_MAD, NULL, dstregtmpmask(temp, RC_MASK_W),
		srcreg(RC_FILE_TEMPORARY, temp),
		srcregswz(RC_FILE_CONSTANT, constant, RC_SWIZZLE_ZZZZ),
		srcregswz(RC_FILE_CONSTANT, constant, RC_SWIZZLE_WWWW));

	r300_transform_SIN_COS(c, inst, temp);
	return 1;
}

/**
 * Replaces DDX/DDY instructions with MOV 0 to avoid using dummy shaders on r300/r400.
 *
 * @warning This explicitly changes the form of DDX and DDY!
 */

int radeonStubDeriv(struct radeon_compiler* c,
	struct rc_instruction* inst,
	void* unused)
{
	if (inst->U.I.Opcode != RC_OPCODE_DDX && inst->U.I.Opcode != RC_OPCODE_DDY)
		return 0;

	inst->U.I.Opcode = RC_OPCODE_MOV;
	inst->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_0000;

	return 1;
}

/**
 * Rewrite DDX/DDY instructions to properly work with r5xx shaders.
 * The r5xx MDH/MDV instruction provides per-quad partial derivatives.
 * It takes the form A*B+C. A and C are set by setting src0. B should be -1.
 *
 * @warning This explicitly changes the form of DDX and DDY!
 */

int radeonTransformDeriv(struct radeon_compiler* c,
	struct rc_instruction* inst,
	void* unused)
{
	if (inst->U.I.Opcode != RC_OPCODE_DDX && inst->U.I.Opcode != RC_OPCODE_DDY)
		return 0;

	inst->U.I.SrcReg[1].Swizzle = RC_SWIZZLE_1111;
	inst->U.I.SrcReg[1].Negate = RC_MASK_XYZW;

	return 1;
}

/**
 * IF Temp[0].x -> IF Temp[0].x
 * ...          -> ...
 * KILL         -> KIL -abs(Temp[0].x)
 * ...          -> ...
 * ENDIF        -> ENDIF
 *
 * === OR ===
 *
 * IF Temp[0].x -> IF Temp[0].x
 * ...          -> ...
 * ELSE         -> ELSE
 * ...	        -> ...
 * KILL	        -> KIL -abs(Temp[0].x)
 * ...          -> ...
 * ENDIF        -> ENDIF
 *
 * === OR ===
 *
 * KILL         -> KIL -none.1111
 *
 * This needs to be done in its own pass, because it might modify the
 * instructions before and after KILL.
 */
void rc_transform_KILL(struct radeon_compiler * c, void *user)
{
	struct rc_instruction * inst;
	for (inst = c->Program.Instructions.Next;
			inst != &c->Program.Instructions; inst = inst->Next) {
		struct rc_instruction * if_inst;
		unsigned in_if = 0;

		if (inst->U.I.Opcode != RC_OPCODE_KILP)
			continue;

		for (if_inst = inst->Prev; if_inst != &c->Program.Instructions;
						if_inst = if_inst->Prev) {

			if (if_inst->U.I.Opcode == RC_OPCODE_IF) {
				in_if = 1;
				break;
			}
		}

		inst->U.I.Opcode = RC_OPCODE_KIL;

		if (!in_if) {
			inst->U.I.SrcReg[0] = negate(builtin_one);
		} else {
			/* This should work even if the KILP is inside the ELSE
			 * block, because -0.0 is considered negative. */
			inst->U.I.SrcReg[0] =
				negate(absolute(if_inst->U.I.SrcReg[0]));
		}
	}
}

int rc_force_output_alpha_to_one(struct radeon_compiler *c,
				 struct rc_instruction *inst, void *data)
{
	struct r300_fragment_program_compiler *fragc = (struct r300_fragment_program_compiler*)c;
	const struct rc_opcode_info *info = rc_get_opcode_info(inst->U.I.Opcode);
	unsigned tmp;

	if (!info->HasDstReg || inst->U.I.DstReg.File != RC_FILE_OUTPUT ||
	    inst->U.I.DstReg.Index == fragc->OutputDepth)
		return 1;

	tmp = rc_find_free_temporary(c);

	/* Insert MOV after inst, set alpha to 1. */
	emit1(c, inst, RC_OPCODE_MOV, NULL, inst->U.I.DstReg,
	      srcregswz(RC_FILE_TEMPORARY, tmp, RC_SWIZZLE_XYZ1));

	/* Re-route the destination of inst to the source of mov. */
	inst->U.I.DstReg.File = RC_FILE_TEMPORARY;
	inst->U.I.DstReg.Index = tmp;

	/* Move the saturate output modifier to the MOV instruction
	 * (for better copy propagation). */
	inst->Next->U.I.SaturateMode = inst->U.I.SaturateMode;
	inst->U.I.SaturateMode = RC_SATURATE_NONE;
	return 1;
}