Mesa (master): llvmpipe: Per quad interpolation.
Jose Fonseca
jrfonseca at kemper.freedesktop.org
Wed Jun 2 17:46:28 UTC 2010
Module: Mesa
Branch: master
Commit: ead58101f91e82279b25676dfe822120be611995
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=ead58101f91e82279b25676dfe822120be611995
Author: José Fonseca <jfonseca at vmware.com>
Date: Wed Jun 2 18:43:35 2010 +0100
llvmpipe: Per quad interpolation.
First interpolate the 4 quads upper left corners, then sub-interpolate
each quad pixel. Do the perspective divide once per quad.
Saves some muls and reciprocates. But doesn't seem to make a
noticeable improvement.
It make the code simpler and more compact, so commiting anyway.
---
src/gallium/drivers/llvmpipe/lp_bld_interp.c | 317 +++++++++++---------------
src/gallium/drivers/llvmpipe/lp_bld_interp.h | 9 +-
2 files changed, 136 insertions(+), 190 deletions(-)
diff --git a/src/gallium/drivers/llvmpipe/lp_bld_interp.c b/src/gallium/drivers/llvmpipe/lp_bld_interp.c
index f0a0a0b..e73733e 100644
--- a/src/gallium/drivers/llvmpipe/lp_bld_interp.c
+++ b/src/gallium/drivers/llvmpipe/lp_bld_interp.c
@@ -101,117 +101,141 @@ coeffs_init(struct lp_build_interp_soa_context *bld,
{
struct lp_build_context *coeff_bld = &bld->coeff_bld;
LLVMBuilderRef builder = coeff_bld->builder;
+ LLVMValueRef zero = LLVMConstNull(coeff_bld->elem_type);
+ LLVMValueRef one = LLVMConstReal(coeff_bld->elem_type, 1.0);
+ LLVMValueRef i0 = LLVMConstInt(LLVMInt32Type(), 0, 0);
+ LLVMValueRef i1 = LLVMConstInt(LLVMInt32Type(), 1, 0);
+ LLVMValueRef i2 = LLVMConstInt(LLVMInt32Type(), 2, 0);
+ LLVMValueRef i3 = LLVMConstInt(LLVMInt32Type(), 3, 0);
+ LLVMValueRef oow = NULL;
unsigned attrib;
unsigned chan;
- for(attrib = 0; attrib < bld->num_attribs; ++attrib) {
+ /* TODO: Use more vector operations */
+
+ for (attrib = 0; attrib < bld->num_attribs; ++attrib) {
const unsigned mask = bld->mask[attrib];
const unsigned interp = bld->interp[attrib];
- for(chan = 0; chan < NUM_CHANNELS; ++chan) {
- if(mask & (1 << chan)) {
+ for (chan = 0; chan < NUM_CHANNELS; ++chan) {
+ if (mask & (1 << chan)) {
LLVMValueRef index = LLVMConstInt(LLVMInt32Type(), attrib*NUM_CHANNELS + chan, 0);
- LLVMValueRef a0 = coeff_bld->undef;
- LLVMValueRef dadx = coeff_bld->undef;
- LLVMValueRef dady = coeff_bld->undef;
-
- switch( interp ) {
+ LLVMValueRef a0 = zero;
+ LLVMValueRef dadx = zero;
+ LLVMValueRef dady = zero;
+ LLVMValueRef dadxy = zero;
+ LLVMValueRef dadq;
+ LLVMValueRef dadq2;
+ LLVMValueRef a;
+
+ switch (interp) {
case LP_INTERP_PERSPECTIVE:
/* fall-through */
case LP_INTERP_LINEAR:
- dadx = LLVMBuildLoad(builder, LLVMBuildGEP(builder, dadx_ptr, &index, 1, ""), "");
- dady = LLVMBuildLoad(builder, LLVMBuildGEP(builder, dady_ptr, &index, 1, ""), "");
- dadx = lp_build_broadcast_scalar(coeff_bld, dadx);
- dady = lp_build_broadcast_scalar(coeff_bld, dady);
- attrib_name(dadx, attrib, chan, ".dadx");
- attrib_name(dady, attrib, chan, ".dady");
+ if (attrib == 0 && chan == 0) {
+ dadxy = dadx = one;
+ }
+ else if (attrib == 0 && chan == 1) {
+ dadxy = dady = one;
+ }
+ else {
+ dadx = LLVMBuildLoad(builder, LLVMBuildGEP(builder, dadx_ptr, &index, 1, ""), "");
+ dady = LLVMBuildLoad(builder, LLVMBuildGEP(builder, dady_ptr, &index, 1, ""), "");
+ dadxy = LLVMBuildAdd(builder, dadx, dady, "");
+ attrib_name(dadx, attrib, chan, ".dadx");
+ attrib_name(dady, attrib, chan, ".dady");
+ attrib_name(dadxy, attrib, chan, ".dadxy");
+ }
/* fall-through */
case LP_INTERP_CONSTANT:
case LP_INTERP_FACING:
a0 = LLVMBuildLoad(builder, LLVMBuildGEP(builder, a0_ptr, &index, 1, ""), "");
- a0 = lp_build_broadcast_scalar(coeff_bld, a0);
attrib_name(a0, attrib, chan, ".a0");
break;
case LP_INTERP_POSITION:
/* Nothing to do as the position coeffs are already setup in slot 0 */
- break;
+ continue;
default:
assert(0);
break;
}
- bld->a0 [attrib][chan] = a0;
- bld->dadx[attrib][chan] = dadx;
- bld->dady[attrib][chan] = dady;
- }
- }
- }
-}
+ /*
+ * dadq = {0, dadx, dady, dadx + dady}
+ */
+ dadq = coeff_bld->undef;
+ dadq = LLVMBuildInsertElement(builder, dadq, zero, i0, "");
+ dadq = LLVMBuildInsertElement(builder, dadq, dadx, i1, "");
+ dadq = LLVMBuildInsertElement(builder, dadq, dady, i2, "");
+ dadq = LLVMBuildInsertElement(builder, dadq, dadxy, i3, "");
-/**
- * Emit LLVM code to compute the fragment shader input attribute values.
- * For example, for a color input, we'll compute red, green, blue and alpha
- * values for the four pixels in a quad.
- * Recall that we're operating on 4-element vectors so each arithmetic
- * operation is operating on the four pixels in a quad.
- */
-static void
-attribs_init(struct lp_build_interp_soa_context *bld)
-{
- struct lp_build_context *coeff_bld = &bld->coeff_bld;
- LLVMValueRef x = bld->pos[0];
- LLVMValueRef y = bld->pos[1];
- LLVMValueRef oow = NULL;
- unsigned attrib;
- unsigned chan;
+ /*
+ * dadq2 = 2 * dq
+ */
- for(attrib = 0; attrib < bld->num_attribs; ++attrib) {
- const unsigned mask = bld->mask[attrib];
- const unsigned interp = bld->interp[attrib];
- for(chan = 0; chan < NUM_CHANNELS; ++chan) {
- if(mask & (1 << chan)) {
- if (interp == LP_INTERP_POSITION) {
- assert(attrib > 0);
- bld->attribs[attrib][chan] = bld->attribs[0][chan];
- }
- else {
- LLVMValueRef a0 = bld->a0 [attrib][chan];
- LLVMValueRef dadx = bld->dadx[attrib][chan];
- LLVMValueRef dady = bld->dady[attrib][chan];
- LLVMValueRef res;
+ dadq2 = LLVMBuildAdd(builder, dadq, dadq, "");
- res = a0;
+ /*
+ * a = a0 + x * dadx + y * dady
+ */
+ if (attrib == 0 && chan == 0) {
+ a = bld->x;
+ }
+ else if (attrib == 0 && chan == 1) {
+ a = bld->y;
+ }
+ else {
+ a = a0;
if (interp != LP_INTERP_CONSTANT &&
interp != LP_INTERP_FACING) {
- /* res = res + x * dadx */
- res = lp_build_add(coeff_bld, res, lp_build_mul(coeff_bld, x, dadx));
- /* res = res + y * dady */
- res = lp_build_add(coeff_bld, res, lp_build_mul(coeff_bld, y, dady));
+ a = LLVMBuildAdd(builder, a,
+ LLVMBuildMul(builder, bld->x, dadx, ""),
+ "");
+ a = LLVMBuildAdd(builder, a,
+ LLVMBuildMul(builder, bld->y, dady, ""),
+ "");
}
+ }
- /* Keep the value of the attribute before perspective divide
- * for faster updates.
- */
- bld->attribs_pre[attrib][chan] = res;
-
- if (interp == LP_INTERP_PERSPECTIVE) {
- LLVMValueRef w = bld->pos[3];
- assert(attrib != 0);
- assert(bld->mask[0] & TGSI_WRITEMASK_W);
- if(!oow)
- oow = lp_build_rcp(coeff_bld, w);
- res = lp_build_mul(coeff_bld, res, oow);
- }
+ /*
+ * a = {a, a, a, a}
+ */
+
+ a = lp_build_broadcast(builder, coeff_bld->vec_type, a);
+
+ /*
+ * Compute the attrib values on the upper-left corner of each quad.
+ */
- attrib_name(res, attrib, chan, "");
+ a = LLVMBuildAdd(builder, a, dadq2, "");
- bld->attribs[attrib][chan] = res;
+ /*
+ * a *= 1 / w
+ * dadq *= 1 / w
+ */
+
+ if (interp == LP_INTERP_PERSPECTIVE) {
+ LLVMValueRef w = bld->a[0][3];
+ assert(attrib != 0);
+ assert(bld->mask[0] & TGSI_WRITEMASK_W);
+ if (!oow) {
+ oow = lp_build_rcp(coeff_bld, w);
+ lp_build_name(oow, "oow");
+ }
+ a = lp_build_mul(coeff_bld, a, oow);
+ dadq = lp_build_mul(coeff_bld, dadq, oow);
}
+
+ attrib_name(a, attrib, chan, ".a");
+ attrib_name(dadq, attrib, chan, ".dadq");
+
+ bld->a [attrib][chan] = a;
+ bld->dadq[attrib][chan] = dadq;
}
}
}
@@ -226,7 +250,7 @@ static void
attribs_update(struct lp_build_interp_soa_context *bld, int quad_index)
{
struct lp_build_context *coeff_bld = &bld->coeff_bld;
- LLVMValueRef oow = NULL;
+ LLVMValueRef shuffle = lp_build_const_int_vec(coeff_bld->type, quad_index);
unsigned attrib;
unsigned chan;
@@ -235,50 +259,36 @@ attribs_update(struct lp_build_interp_soa_context *bld, int quad_index)
for(attrib = 0; attrib < bld->num_attribs; ++attrib) {
const unsigned mask = bld->mask[attrib];
const unsigned interp = bld->interp[attrib];
+ for(chan = 0; chan < NUM_CHANNELS; ++chan) {
+ if(mask & (1 << chan)) {
+ LLVMValueRef a = coeff_bld->undef;
+ if (interp == LP_INTERP_CONSTANT &&
+ interp == LP_INTERP_FACING) {
+ a = bld->a[attrib][chan];
+ }
+ else if (interp == LP_INTERP_POSITION) {
+ assert(attrib > 0);
+ a = bld->attribs[0][chan];
+ }
+ else {
+ a = bld->a[attrib][chan];
- if (interp != LP_INTERP_CONSTANT &&
- interp != LP_INTERP_FACING) {
- for(chan = 0; chan < NUM_CHANNELS; ++chan) {
- if(mask & (1 << chan)) {
- if (interp == LP_INTERP_POSITION) {
- assert(attrib > 0);
- bld->attribs[attrib][chan] = bld->attribs[0][chan];
- }
- else {
- LLVMValueRef dadx = bld->dadx[attrib][chan];
- LLVMValueRef dady = bld->dady[attrib][chan];
- LLVMValueRef res;
-
- res = bld->attribs_pre[attrib][chan];
-
- if (quad_index == 1 || quad_index == 3) {
- /* top-right or bottom-right quad */
- /* build res = res + dadx + dadx */
- res = lp_build_add(coeff_bld, res, dadx);
- res = lp_build_add(coeff_bld, res, dadx);
- }
-
- if (quad_index == 2 || quad_index == 3) {
- /* bottom-left or bottom-right quad */
- /* build res = res + dady + dady */
- res = lp_build_add(coeff_bld, res, dady);
- res = lp_build_add(coeff_bld, res, dady);
- }
-
- if (interp == LP_INTERP_PERSPECTIVE) {
- LLVMValueRef w = bld->pos[3];
- assert(attrib != 0);
- assert(bld->mask[0] & TGSI_WRITEMASK_W);
- if(!oow)
- oow = lp_build_rcp(coeff_bld, w);
- res = lp_build_mul(coeff_bld, res, oow);
- }
-
- attrib_name(res, attrib, chan, "");
-
- bld->attribs[attrib][chan] = res;
- }
+ /*
+ * Broadcast the attribute value for this quad into all elements
+ */
+
+ a = LLVMBuildShuffleVector(coeff_bld->builder,
+ a, coeff_bld->undef, shuffle, "");
+
+ /*
+ * Add the derivatives
+ */
+
+ a = lp_build_add(coeff_bld, a, bld->dadq[attrib][chan]);
+
+ attrib_name(a, attrib, chan, "");
}
+ bld->attribs[attrib][chan] = a;
}
}
}
@@ -296,70 +306,9 @@ pos_init(struct lp_build_interp_soa_context *bld,
LLVMValueRef y0)
{
struct lp_build_context *coeff_bld = &bld->coeff_bld;
- LLVMValueRef x_offsets[QUAD_SIZE];
- LLVMValueRef y_offsets[QUAD_SIZE];
- unsigned i;
-
- /*
- * Derive from the quad's upper left scalar coordinates the coordinates for
- * all other quad pixels
- */
-
- x0 = lp_build_broadcast(coeff_bld->builder, coeff_bld->int_vec_type, x0);
- y0 = lp_build_broadcast(coeff_bld->builder, coeff_bld->int_vec_type, y0);
-
- for(i = 0; i < QUAD_SIZE; ++i) {
- x_offsets[i] = LLVMConstInt(coeff_bld->int_elem_type, quad_offset_x[i], 0);
- y_offsets[i] = LLVMConstInt(coeff_bld->int_elem_type, quad_offset_y[i], 0);
- }
- x0 = LLVMBuildAdd(coeff_bld->builder, x0, LLVMConstVector(x_offsets, QUAD_SIZE), "");
- y0 = LLVMBuildAdd(coeff_bld->builder, y0, LLVMConstVector(y_offsets, QUAD_SIZE), "");
-
- x0 = LLVMBuildSIToFP(coeff_bld->builder, x0, coeff_bld->vec_type, "");
- y0 = LLVMBuildSIToFP(coeff_bld->builder, y0, coeff_bld->vec_type, "");
-
- lp_build_name(x0, "pos.x");
- lp_build_name(y0, "pos.y");
-
- bld->attribs[0][0] = x0;
- bld->attribs[0][1] = y0;
-}
-
-
-/**
- * Update quad position values when moving to the next quad.
- */
-static void
-pos_update(struct lp_build_interp_soa_context *bld, int quad_index)
-{
- struct lp_build_context *coeff_bld = &bld->coeff_bld;
- LLVMValueRef x = bld->attribs[0][0];
- LLVMValueRef y = bld->attribs[0][1];
- const int xstep = 2, ystep = 2;
-
- if (quad_index == 1 || quad_index == 3) {
- /* top-right or bottom-right quad in block */
- /* build x += xstep */
- x = lp_build_add(coeff_bld, x,
- lp_build_const_vec(coeff_bld->type, xstep));
- }
-
- if (quad_index == 2) {
- /* bottom-left quad in block */
- /* build y += ystep */
- y = lp_build_add(coeff_bld, y,
- lp_build_const_vec(coeff_bld->type, ystep));
- /* build x -= xstep */
- x = lp_build_sub(coeff_bld, x,
- lp_build_const_vec(coeff_bld->type, xstep));
- }
-
- lp_build_name(x, "pos.x");
- lp_build_name(y, "pos.y");
-
- bld->attribs[0][0] = x;
- bld->attribs[0][1] = y;
+ bld->x = LLVMBuildSIToFP(coeff_bld->builder, x0, coeff_bld->elem_type, "");
+ bld->y = LLVMBuildSIToFP(coeff_bld->builder, y0, coeff_bld->elem_type, "");
}
@@ -401,7 +350,7 @@ lp_build_interp_soa_init(struct lp_build_interp_soa_context *bld,
/* Position */
bld->num_attribs = 1;
- bld->mask[0] = TGSI_WRITEMASK_ZW;
+ bld->mask[0] = TGSI_WRITEMASK_XYZW;
bld->interp[0] = LP_INTERP_LINEAR;
/* Inputs */
@@ -418,11 +367,11 @@ lp_build_interp_soa_init(struct lp_build_interp_soa_context *bld,
}
}
- coeffs_init(bld, a0_ptr, dadx_ptr, dady_ptr);
-
pos_init(bld, x0, y0);
- attribs_init(bld);
+ coeffs_init(bld, a0_ptr, dadx_ptr, dady_ptr);
+
+ attribs_update(bld, 0);
}
@@ -435,7 +384,5 @@ lp_build_interp_soa_update(struct lp_build_interp_soa_context *bld,
{
assert(quad_index < 4);
- pos_update(bld, quad_index);
-
attribs_update(bld, quad_index);
}
diff --git a/src/gallium/drivers/llvmpipe/lp_bld_interp.h b/src/gallium/drivers/llvmpipe/lp_bld_interp.h
index 45a4307..2905513 100644
--- a/src/gallium/drivers/llvmpipe/lp_bld_interp.h
+++ b/src/gallium/drivers/llvmpipe/lp_bld_interp.h
@@ -58,12 +58,11 @@ struct lp_build_interp_soa_context
unsigned mask[1 + PIPE_MAX_SHADER_INPUTS]; /**< TGSI_WRITE_MASK_x */
enum lp_interp interp[1 + PIPE_MAX_SHADER_INPUTS];
- LLVMValueRef a0 [1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
- LLVMValueRef dadx[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
- LLVMValueRef dady[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
+ LLVMValueRef x;
+ LLVMValueRef y;
- /* Attribute values before perspective divide */
- LLVMValueRef attribs_pre[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
+ LLVMValueRef a [1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
+ LLVMValueRef dadq[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
LLVMValueRef attribs[1 + PIPE_MAX_SHADER_INPUTS][NUM_CHANNELS];
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