Mesa (main): r300: merge simple movs with constant swizzles together
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Sun Jun 5 21:47:43 UTC 2022
Module: Mesa
Branch: main
Commit: 6c2959c0256167bc97ed338e12e0543a967f2fc3
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=6c2959c0256167bc97ed338e12e0543a967f2fc3
Author: Pavel Ondračka <pavel.ondracka at gmail.com>
Date: Fri May 20 11:11:07 2022 +0200
r300: merge simple movs with constant swizzles together
This pass will merge instructions like these
MOV output[0].x, temp[5].x___;
MOV output[0].yzw, none._001;
into
MOV output[0].xyzw, temp[5].x001;
It is currently very careful with control flow and dependency
tracking, so there is still room for improvements.
Shader-db stats with RV530:
total instructions in shared programs: 132486 -> 132256 (-0.17%)
instructions in affected programs: 6186 -> 5956 (-3.72%)
helped: 65
HURT: 0
total temps in shared programs: 18035 -> 18014 (-0.12%)
temps in affected programs: 295 -> 274 (-7.12%)
helped: 22
HURT: 1
Signed-off-by: Pavel Ondračka <pavel.ondracka at gmail.com>
Reviewed-by: Filip Gawin <filip at gawin.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16657>
---
.../drivers/r300/compiler/radeon_optimize.c | 82 ++++++++++++++++++++++
1 file changed, 82 insertions(+)
diff --git a/src/gallium/drivers/r300/compiler/radeon_optimize.c b/src/gallium/drivers/r300/compiler/radeon_optimize.c
index 5a9f4a529df..2609534187d 100644
--- a/src/gallium/drivers/r300/compiler/radeon_optimize.c
+++ b/src/gallium/drivers/r300/compiler/radeon_optimize.c
@@ -887,6 +887,86 @@ static int peephole(struct radeon_compiler * c, struct rc_instruction * inst)
return 0;
}
+static unsigned int merge_swizzles(unsigned int swz1, unsigned int swz2) {
+ unsigned int new_swz = rc_init_swizzle(RC_SWIZZLE_UNUSED, 0);
+ for (unsigned int chan = 0; chan < 4; chan++) {
+ unsigned int swz = GET_SWZ(swz1, chan);
+ if (swz != RC_SWIZZLE_UNUSED) {
+ SET_SWZ(new_swz, chan, swz);
+ continue;
+ }
+ swz = GET_SWZ(swz2, chan);
+ SET_SWZ(new_swz, chan, swz);
+ }
+ return new_swz;
+}
+
+static int merge_movs(struct radeon_compiler * c, struct rc_instruction * inst)
+{
+ unsigned int orig_dst_reg = inst->U.I.DstReg.Index;
+ unsigned int orig_dst_file = inst->U.I.DstReg.File;
+ unsigned int orig_dst_wmask = inst->U.I.DstReg.WriteMask;
+ unsigned int orig_src_reg = inst->U.I.SrcReg[0].Index;
+ unsigned int orig_src_file = inst->U.I.SrcReg[0].File;
+
+ struct rc_instruction * cur = inst;
+ while (cur!= &c->Program.Instructions) {
+ cur = cur->Next;
+ const struct rc_opcode_info * opcode = rc_get_opcode_info(cur->U.I.Opcode);
+
+ /* Keep it simple for now and stop when encountering any
+ * control flow.
+ */
+ if (opcode->IsFlowControl)
+ return 0;
+
+ /* Stop when the original destination is overwritten */
+ if (orig_dst_reg == cur->U.I.DstReg.Index &&
+ orig_dst_file == cur->U.I.DstReg.File &&
+ (orig_dst_wmask & cur->U.I.DstReg.WriteMask) != 0)
+ return 0;
+
+ /* Stop the search when the original instruction destination
+ * is used as a source for anything.
+ */
+ for (unsigned i = 0; i < opcode->NumSrcRegs; i++) {
+ if (cur->U.I.SrcReg[i].File == orig_dst_file &&
+ cur->U.I.SrcReg[i].Index == orig_dst_reg)
+ return 0;
+ }
+
+ if (cur->U.I.Opcode == RC_OPCODE_MOV &&
+ cur->U.I.DstReg.File == orig_dst_file &&
+ cur->U.I.DstReg.Index == orig_dst_reg &&
+ (cur->U.I.DstReg.WriteMask & orig_dst_wmask) == 0) {
+
+ /* We can merge the movs if one of them is from inline constant */
+ if (cur->U.I.SrcReg[0].File == RC_FILE_NONE ||
+ orig_src_file == RC_FILE_NONE) {
+ cur->U.I.DstReg.WriteMask |= orig_dst_wmask;
+
+ if (cur->U.I.SrcReg[0].File == RC_FILE_NONE) {
+ cur->U.I.SrcReg[0].File = orig_src_file;
+ cur->U.I.SrcReg[0].Index = orig_src_reg;
+ cur->U.I.SrcReg[0].Abs = inst->U.I.SrcReg[0].Abs;
+ cur->U.I.SrcReg[0].RelAddr = inst->U.I.SrcReg[0].RelAddr;
+ }
+ cur->U.I.SrcReg[0].Swizzle =
+ merge_swizzles(cur->U.I.SrcReg[0].Swizzle,
+ inst->U.I.SrcReg[0].Swizzle);
+
+ cur->U.I.SrcReg[0].Negate |= inst->U.I.SrcReg[0].Negate;
+
+ /* finally delete the original mov */
+ rc_remove_instruction(inst);
+
+ return 1;
+ }
+ }
+ }
+ return 0;
+}
+
void rc_optimize(struct radeon_compiler * c, void *user)
{
struct rc_instruction * inst = c->Program.Instructions.Next;
@@ -900,6 +980,8 @@ void rc_optimize(struct radeon_compiler * c, void *user)
continue;
if (cur->U.I.Opcode == RC_OPCODE_MOV) {
+ if (merge_movs(c,cur))
+ continue;
copy_propagate(c, cur);
/* cur may no longer be part of the program */
}
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