[Mesa-dev] [PATCH] nv50/ir: Add mul and mod constant optimizations

[Mark Menzynski]

Optimizations for 0/n, 1/n and 0%n.
No changes in shader db tests, because it is never used here, but it
should become handy.

Signed-off-by: Mark Menzynski <mmenzyns at redhat.com>
---
 .../nouveau/codegen/nv50_ir_peephole.cpp      | 30 +++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
index 0b3220903b9..12069e19808 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
@@ -1177,10 +1177,28 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue &imm0, int s)
       break;
 
    case OP_DIV:
-      if (s != 1 || (i->dType != TYPE_S32 && i->dType != TYPE_U32))
+      if (i->dType != TYPE_S32 && i->dType != TYPE_U32)
          break;
+
       bld.setPosition(i, false);
-      if (imm0.reg.data.u32 == 0) {
+      if (s == 0) {
+         if (imm0.reg.data.u32 == 0) {
+            i->op = OP_MOV;
+            i->setSrc(1, NULL);
+         }
+         else if (imm0.reg.data.u32 == 1) {
+            Value *tA, *tB;
+            Instruction *slct;
+
+            tA = bld.mkOp1v(OP_ABS, TYPE_U32, bld.getSSA(), i->getSrc(1));
+            tB = bld.mkOp2v(OP_ADD, TYPE_S32, bld.getSSA(), tA, bld.loadImm(NULL, -1));
+            slct = bld.mkCmp(OP_SLCT, CC_GT, i->dType, bld.getSSA(), TYPE_U32, bld.loadImm(NULL, 0), i->getSrc(1), tB);
+            i->def(0).replace(slct->getDef(0), false);
+         }
+         break;
+      }
+
+      if (s != 1 || imm0.reg.data.u32 == 0) {
          break;
       } else
       if (imm0.reg.data.u32 == 1) {
@@ -1259,6 +1277,14 @@ ConstantFolding::opnd(Instruction *i, ImmediateValue &imm0, int s)
       break;
 
    case OP_MOD:
+      if (s == 0) {
+         if (imm0.reg.data.u32 == 0) {
+            i->op = OP_MOV;
+            i->setSrc(1, NULL);
+         }
+         break;
+      }
+
       if (s == 1 && imm0.isPow2()) {
          bld.setPosition(i, false);
          if (i->sType == TYPE_U32) {
-- 
2.21.0