If the exponent is a small integer immediate value, we can lower POW to
MULs instead to save a few instructions. Also MUL instructions execute
faster than what we lower POW in the default case to.
score change for GpuTest /test=pixmark_piano /benchmark /no_scorebox
/msaa=0 /benchmark_duration_ms=60000 /width=1024 /height=640:
1045 -> 1060
changes in shader-db:
total instructions in shared programs : 4350261 -> 4349451 (-0.02%)
total gprs used in shared programs : 525853 -> 525861 (0.00%)
total local used in shared programs : 30081 -> 30081 (0.00%)
total bytes used in shared programs : 39865176 -> 39857712 (-0.02%)
local gpr inst bytes
helped 0 4 313 313
hurt 0 12 1 1
Signed-off-by: Karol Herbst <karolher...@gmail.com>
---
.../drivers/nouveau/codegen/nv50_ir_build_util.cpp | 49 ++++++++++++++++++++++
1 file changed, 49 insertions(+)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_build_util.cpp
b/src/gallium/drivers/nouveau/codegen/nv50_ir_build_util.cpp
index 5756e1b4d4..b31dcec1ab 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_build_util.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_build_util.cpp
@@ -640,6 +640,55 @@ bool
BuildUtil::lowerPOW(Instruction *i)
{
LValue *val = getScratch();
+ ImmediateValue imm;
+
+ if (i->src(1).getImmediate(imm)) {
+ Value *src = i->getSrc(0);
+ if (imm.isInteger(0)) {
+ i->op = OP_MOV;
+ i->setSrc(0, loadImm(NULL, 1));
+ i->setSrc(1, NULL);
+ return true;
+ } else
+ if (imm.isInteger(1)) {
+ i->op = OP_MOV;
+ i->setSrc(1, NULL);
+ return true;
+ } else
+ if (imm.isInteger(2)) {
+ i->op = OP_MUL;
+ i->setSrc(1, src);
+ return true;
+ } else
+ if (imm.isInteger(3)) {
+ mkOp2(OP_MUL, i->dType, val, src, src);
+ i->op = OP_MUL;
+ i->setSrc(1, val);
+ return true;
+ } else
+ if (imm.isInteger(4)) {
+ mkOp2(OP_MUL, i->dType, val, src, src);
+ i->op = OP_MUL;
+ i->setSrc(0, val);
+ i->setSrc(1, val);
+ return true;
+ } else
+ if (imm.isInteger(5)) {
+ mkOp2(OP_MUL, i->dType, val, src, src);
+ mkOp2(OP_MUL, i->dType, val, val, val);
+ i->op = OP_MUL;
+ i->setSrc(1, val);
+ return true;
+ } else
+ if (imm.isInteger(8)) {
+ mkOp2(OP_MUL, i->dType, val, src, src);
+ mkOp2(OP_MUL, i->dType, val, val, val);
+ i->op = OP_MUL;
+ i->setSrc(0, val);
+ i->setSrc(1, val);
+ return true;
+ }
+ }
mkOp1(OP_LG2, TYPE_F32, val, i->getSrc(0));
mkOp2(OP_MUL, TYPE_F32, val, i->getSrc(1), val)->dnz = 1;
--
2.13.1
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