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mesa: Improve the eliminate-move-use to work across multiple instructions.

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This shaves more instructions off of the VS of my GL demo, but no
performance difference this time at n=6.  This also fixes a regression
that was in this path, which is now piglit's glsl-vs-mov-after-deref.
This commit is contained in:
Eric Anholt
2009-11-11 13:26:26 -08:00
parent 654122ba7b
commit d6690ce15f
1 changed files with 80 additions and 36 deletions
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src/mesa/shader/prog_optimize.c
+80 -36
View File
@@ -65,6 +65,7 @@ get_src_arg_mask(const struct prog_instruction *inst, int arg)
case OPCODE_DP2:
return WRITEMASK_XY;
case OPCODE_DP3:
case OPCODE_XPD:
return WRITEMASK_XYZ;
default:
return WRITEMASK_XYZW;
@@ -396,6 +397,26 @@ find_next_temp_use(const struct gl_program *prog, GLuint start, GLuint index)
return END;
}
static GLboolean _mesa_is_flow_control_opcode(enum prog_opcode opcode)
{
switch (opcode) {
case OPCODE_BGNLOOP:
case OPCODE_BGNSUB:
case OPCODE_BRA:
case OPCODE_CAL:
case OPCODE_CONT:
case OPCODE_IF:
case OPCODE_ELSE:
case OPCODE_END:
case OPCODE_ENDIF:
case OPCODE_ENDLOOP:
case OPCODE_ENDSUB:
case OPCODE_RET:
return GL_TRUE;
default:
return GL_FALSE;
}
}
/**
* Try to remove use of extraneous MOV instructions, to free them up for dead
@@ -404,7 +425,7 @@ find_next_temp_use(const struct gl_program *prog, GLuint start, GLuint index)
static void
_mesa_remove_extra_move_use(struct gl_program *prog)
{
GLuint i;
GLuint i, j;
if (dbg) {
_mesa_printf("Optimize: Begin remove extra move use\n");
@@ -414,63 +435,86 @@ _mesa_remove_extra_move_use(struct gl_program *prog)
/*
* Look for sequences such as this:
* MOV tmpX, arg0;
* ...
* FOO tmpY, tmpX, arg1;
* and convert into:
* MOV tmpX, arg0;
* ...
* FOO tmpY, arg0, arg1;
*/
for (i = 0; i < prog->NumInstructions - 1; i++) {
const struct prog_instruction *mov = prog->Instructions + i;
struct prog_instruction *inst2 = prog->Instructions + i + 1;
int arg;
if (mov->Opcode != OPCODE_MOV ||
mov->DstReg.File != PROGRAM_TEMPORARY ||
mov->DstReg.RelAddr ||
mov->DstReg.CondMask != COND_TR ||
mov->SaturateMode != SATURATE_OFF)
mov->SaturateMode != SATURATE_OFF ||
mov->SrcReg[0].RelAddr)
continue;
for (arg = 0; arg < _mesa_num_inst_src_regs(inst2->Opcode); arg++) {
int comp;
int read_mask = get_src_arg_mask(inst2, arg);
/* Walk through remaining instructions until the or src reg gets
* rewritten or we get into some flow-control, eliminating the use of
* this MOV.
*/
for (j = i + 1; j < prog->NumInstructions; j++) {
struct prog_instruction *inst2 = prog->Instructions + j;
int arg;
if (inst2->SrcReg[arg].File != mov->DstReg.File ||
inst2->SrcReg[arg].Index != mov->DstReg.Index ||
inst2->SrcReg[arg].RelAddr ||
inst2->SrcReg[arg].Abs)
continue;
if (_mesa_is_flow_control_opcode(inst2->Opcode))
break;
/* Check that all the sources for this arg of inst2 come from inst1
* or constants.
*/
for (comp = 0; comp < 4; comp++) {
int src_swz = GET_SWZ(inst2->SrcReg[arg].Swizzle, comp);
/* First rewrite this instruction's args if appropriate. */
for (arg = 0; arg < _mesa_num_inst_src_regs(inst2->Opcode); arg++) {
int comp;
int read_mask = get_src_arg_mask(inst2, arg);
/* If the MOV didn't write that channel, can't use it. */
if ((read_mask & (1 << comp)) &&
src_swz <= SWIZZLE_W &&
(mov->DstReg.WriteMask & (1 << src_swz)) == 0)
break;
}
if (comp != 4)
continue;
if (inst2->SrcReg[arg].File != mov->DstReg.File ||
inst2->SrcReg[arg].Index != mov->DstReg.Index ||
inst2->SrcReg[arg].RelAddr ||
inst2->SrcReg[arg].Abs)
continue;
/* Adjust the swizzles of inst2 to point at MOV's source */
for (comp = 0; comp < 4; comp++) {
int inst2_swz = GET_SWZ(inst2->SrcReg[arg].Swizzle, comp);
/* Check that all the sources for this arg of inst2 come from inst1
* or constants.
*/
for (comp = 0; comp < 4; comp++) {
int src_swz = GET_SWZ(inst2->SrcReg[arg].Swizzle, comp);
if (inst2_swz <= SWIZZLE_W) {
GLuint s = GET_SWZ(mov->SrcReg[0].Swizzle, inst2_swz);
inst2->SrcReg[arg].Swizzle &= ~(7 << (3 * comp));
inst2->SrcReg[arg].Swizzle |= s << (3 * comp);
inst2->SrcReg[arg].Negate ^= (((mov->SrcReg[0].Negate >>
inst2_swz) & 0x1) << comp);
/* If the MOV didn't write that channel, can't use it. */
if ((read_mask & (1 << comp)) &&
src_swz <= SWIZZLE_W &&
(mov->DstReg.WriteMask & (1 << src_swz)) == 0)
break;
}
if (comp != 4)
continue;
/* Adjust the swizzles of inst2 to point at MOV's source */
for (comp = 0; comp < 4; comp++) {
int inst2_swz = GET_SWZ(inst2->SrcReg[arg].Swizzle, comp);
if (inst2_swz <= SWIZZLE_W) {
GLuint s = GET_SWZ(mov->SrcReg[0].Swizzle, inst2_swz);
inst2->SrcReg[arg].Swizzle &= ~(7 << (3 * comp));
inst2->SrcReg[arg].Swizzle |= s << (3 * comp);
inst2->SrcReg[arg].Negate ^= (((mov->SrcReg[0].Negate >>
inst2_swz) & 0x1) << comp);
}
}
inst2->SrcReg[arg].File = mov->SrcReg[0].File;
inst2->SrcReg[arg].Index = mov->SrcReg[0].Index;
}
inst2->SrcReg[arg].File = mov->SrcReg[0].File;
inst2->SrcReg[arg].Index = mov->SrcReg[0].Index;
/* If this instruction overwrote part of the move, our time is up. */
if ((inst2->DstReg.File == mov->DstReg.File &&
(inst2->DstReg.RelAddr ||
inst2->DstReg.Index == mov->DstReg.Index)) ||
(inst2->DstReg.File == mov->SrcReg[0].File &&
(inst2->DstReg.RelAddr ||
inst2->DstReg.Index == mov->SrcReg[0].Index)))
break;
}
}