Mesa (master): r300/compiler: Implement constant folding
Marek Olšák
mareko at kemper.freedesktop.org
Wed May 19 01:20:35 UTC 2010
Module: Mesa
Branch: master
Commit: 1712643a297d66b7a45155fc88937109935687fb
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=1712643a297d66b7a45155fc88937109935687fb
Author: Nicolai Hähnle <nhaehnle at gmail.com>
Date: Sun Oct 11 17:11:11 2009 +0200
r300/compiler: Implement constant folding
Signed-off-by: Nicolai Hähnle <nhaehnle at gmail.com>
---
.../drivers/dri/r300/compiler/radeon_optimize.c | 216 +++++++++++++++++++-
1 files changed, 215 insertions(+), 1 deletions(-)
diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c b/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c
index fd608cc..21d7210 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c
@@ -28,6 +28,7 @@
#include "radeon_dataflow.h"
#include "radeon_compiler.h"
+#include "radeon_swizzle.h"
static struct rc_src_register chain_srcregs(struct rc_src_register outer, struct rc_src_register inner)
@@ -219,6 +220,215 @@ static void peephole(struct radeon_compiler * c, struct rc_instruction * inst_mo
rc_remove_instruction(inst_mov);
}
+/**
+ * Check if a source register is actually always the same
+ * swizzle constant.
+ */
+static int is_src_uniform_constant(struct rc_src_register src,
+ rc_swizzle * pswz, unsigned int * pnegate)
+{
+ int have_used = 0;
+
+ if (src.File != RC_FILE_NONE) {
+ *pswz = 0;
+ return 0;
+ }
+
+ for(unsigned int chan = 0; chan < 4; ++chan) {
+ unsigned int swz = GET_SWZ(src.Swizzle, chan);
+ if (swz < 4) {
+ *pswz = 0;
+ return 0;
+ }
+ if (swz == RC_SWIZZLE_UNUSED)
+ continue;
+
+ if (!have_used) {
+ *pswz = swz;
+ *pnegate = GET_BIT(src.Negate, chan);
+ have_used = 1;
+ } else {
+ if (swz != *pswz || *pnegate != GET_BIT(src.Negate, chan)) {
+ *pswz = 0;
+ return 0;
+ }
+ }
+ }
+
+ return 1;
+}
+
+
+static void constant_folding_mad(struct rc_instruction * inst)
+{
+ rc_swizzle swz;
+ unsigned int negate;
+
+ if (is_src_uniform_constant(inst->U.I.SrcReg[2], &swz, &negate)) {
+ if (swz == RC_SWIZZLE_ZERO) {
+ inst->U.I.Opcode = RC_OPCODE_MUL;
+ return;
+ }
+ }
+
+ if (is_src_uniform_constant(inst->U.I.SrcReg[1], &swz, &negate)) {
+ if (swz == RC_SWIZZLE_ONE) {
+ inst->U.I.Opcode = RC_OPCODE_ADD;
+ if (negate)
+ inst->U.I.SrcReg[0].Negate ^= RC_MASK_XYZW;
+ inst->U.I.SrcReg[1] = inst->U.I.SrcReg[2];
+ return;
+ } else if (swz == RC_SWIZZLE_ZERO) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ inst->U.I.SrcReg[0] = inst->U.I.SrcReg[2];
+ return;
+ }
+ }
+
+ if (is_src_uniform_constant(inst->U.I.SrcReg[0], &swz, &negate)) {
+ if (swz == RC_SWIZZLE_ONE) {
+ inst->U.I.Opcode = RC_OPCODE_ADD;
+ if (negate)
+ inst->U.I.SrcReg[1].Negate ^= RC_MASK_XYZW;
+ inst->U.I.SrcReg[0] = inst->U.I.SrcReg[2];
+ return;
+ } else if (swz == RC_SWIZZLE_ZERO) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ inst->U.I.SrcReg[0] = inst->U.I.SrcReg[2];
+ return;
+ }
+ }
+}
+
+static void constant_folding_mul(struct rc_instruction * inst)
+{
+ rc_swizzle swz;
+ unsigned int negate;
+
+ if (is_src_uniform_constant(inst->U.I.SrcReg[0], &swz, &negate)) {
+ if (swz == RC_SWIZZLE_ONE) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ inst->U.I.SrcReg[0] = inst->U.I.SrcReg[1];
+ if (negate)
+ inst->U.I.SrcReg[0].Negate ^= RC_MASK_XYZW;
+ return;
+ } else if (swz == RC_SWIZZLE_ZERO) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ inst->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_0000;
+ return;
+ }
+ }
+
+ if (is_src_uniform_constant(inst->U.I.SrcReg[1], &swz, &negate)) {
+ if (swz == RC_SWIZZLE_ONE) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ if (negate)
+ inst->U.I.SrcReg[0].Negate ^= RC_MASK_XYZW;
+ return;
+ } else if (swz == RC_SWIZZLE_ZERO) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ inst->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_0000;
+ return;
+ }
+ }
+}
+
+static void constant_folding_add(struct rc_instruction * inst)
+{
+ rc_swizzle swz;
+ unsigned int negate;
+
+ if (is_src_uniform_constant(inst->U.I.SrcReg[0], &swz, &negate)) {
+ if (swz == RC_SWIZZLE_ZERO) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ inst->U.I.SrcReg[0] = inst->U.I.SrcReg[1];
+ return;
+ }
+ }
+
+ if (is_src_uniform_constant(inst->U.I.SrcReg[1], &swz, &negate)) {
+ if (swz == RC_SWIZZLE_ZERO) {
+ inst->U.I.Opcode = RC_OPCODE_MOV;
+ return;
+ }
+ }
+}
+
+
+/**
+ * Replace 0.0, 1.0 and 0.5 immediate constants by their
+ * respective swizzles. Simplify instructions like ADD dst, src, 0;
+ */
+static void constant_folding(struct radeon_compiler * c, struct rc_instruction * inst)
+{
+ const struct rc_opcode_info * opcode = rc_get_opcode_info(inst->U.I.Opcode);
+
+ /* Replace 0.0, 1.0 and 0.5 immediates by their explicit swizzles */
+ for(unsigned int src = 0; src < opcode->NumSrcRegs; ++src) {
+ if (inst->U.I.SrcReg[src].File != RC_FILE_CONSTANT ||
+ inst->U.I.SrcReg[src].RelAddr ||
+ inst->U.I.SrcReg[src].Index >= c->Program.Constants.Count)
+ continue;
+
+ struct rc_constant * constant =
+ &c->Program.Constants.Constants[inst->U.I.SrcReg[src].Index];
+
+ if (constant->Type != RC_CONSTANT_IMMEDIATE)
+ continue;
+
+ struct rc_src_register newsrc = inst->U.I.SrcReg[src];
+ int have_real_reference = 0;
+ for(unsigned int chan = 0; chan < 4; ++chan) {
+ unsigned int swz = GET_SWZ(newsrc.Swizzle, chan);
+ if (swz >= 4)
+ continue;
+
+ unsigned int newswz;
+ float imm = constant->u.Immediate[swz];
+ float baseimm = imm;
+ if (imm < 0.0)
+ baseimm = -baseimm;
+
+ if (baseimm == 0.0) {
+ newswz = RC_SWIZZLE_ZERO;
+ } else if (baseimm == 1.0) {
+ newswz = RC_SWIZZLE_ONE;
+ } else if (baseimm == 0.5) {
+ newswz = RC_SWIZZLE_HALF;
+ } else {
+ have_real_reference = 1;
+ continue;
+ }
+
+ SET_SWZ(newsrc.Swizzle, chan, newswz);
+ if (imm < 0.0 && !newsrc.Abs)
+ newsrc.Negate ^= 1 << chan;
+ }
+
+ if (!have_real_reference) {
+ newsrc.File = RC_FILE_NONE;
+ newsrc.Index = 0;
+ }
+
+ /* don't make the swizzle worse */
+ if (!c->SwizzleCaps->IsNative(inst->U.I.Opcode, newsrc) &&
+ c->SwizzleCaps->IsNative(inst->U.I.Opcode, inst->U.I.SrcReg[src]))
+ continue;
+
+ inst->U.I.SrcReg[src] = newsrc;
+ }
+
+ /* Simplify instructions based on constants */
+ if (inst->U.I.Opcode == RC_OPCODE_MAD)
+ constant_folding_mad(inst);
+
+ /* note: MAD can simplify to MUL or ADD */
+ if (inst->U.I.Opcode == RC_OPCODE_MUL)
+ constant_folding_mul(inst);
+ else if (inst->U.I.Opcode == RC_OPCODE_ADD)
+ constant_folding_add(inst);
+}
+
void rc_optimize(struct radeon_compiler * c)
{
struct rc_instruction * inst = c->Program.Instructions.Next;
@@ -226,7 +436,11 @@ void rc_optimize(struct radeon_compiler * c)
struct rc_instruction * cur = inst;
inst = inst->Next;
- if (cur->U.I.Opcode == RC_OPCODE_MOV)
+ constant_folding(c, cur);
+
+ if (cur->U.I.Opcode == RC_OPCODE_MOV) {
peephole(c, cur);
+ /* cur may no longer be part of the program */
+ }
}
}
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