[Mesa-dev] [PATCH 3/6] nv50/ir: optimize neg(add(bool, 1)) to bool for OP_SET and OP_SLCT

[Karol Herbst]

From: Karol Herbst <git at karolherbst.de>

helps shaders in saints row IV, bioshock infinite and shadow warrior

total instructions in shared programs : 1922121 -> 1911112 (-0.57%)
total gprs used in shared programs    : 251878 -> 251739 (-0.06%)
total local used in shared programs   : 5673 -> 5673 (0.00%)
total bytes used in shared programs   : 17624144 -> 17523440 (-0.57%)

                local        gpr       inst      bytes
    helped           0         137         720         720
      hurt           0           8           0           0

Signed-off-by: Karol Herbst <nouveau at karolherbst.de>
---
 .../drivers/nouveau/codegen/nv50_ir_peephole.cpp   | 28 ++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
index 9c60ea1..8dc0844 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
@@ -1510,6 +1510,7 @@ private:
    void handleCVT_CVT(Instruction *);
    void handleCVT_EXTBF(Instruction *);
    void handleSUCLAMP(Instruction *);
+   void handleNEG(Instruction *);
 
    BuildUtil bld;
 };
@@ -1982,6 +1983,30 @@ AlgebraicOpt::handleSUCLAMP(Instruction *insn)
    insn->setSrc(0, add->getSrc(s));
 }
 
+void
+AlgebraicOpt::handleNEG(Instruction *i) {
+   Value *src = i->getSrc(0);
+   if (src->getInsn()->op == OP_AND) {
+      ImmediateValue immd;
+      int b = 1;
+      if (!src->getInsn()->src(0).getImmediate(immd)) {
+         if (!src->getInsn()->src(1).getImmediate(immd))
+            return;
+         b = 0;
+      }
+
+      if (immd.isInteger(1)) {
+         Value *srcAnd = src->getInsn()->getSrc(b);
+         operation op = srcAnd->getInsn()->op;
+         if (op == OP_SET || op == OP_SLCT) {
+            i->op = OP_MOV;
+            i->setSrc(0, srcAnd);
+            return;
+         }
+      }
+   }
+}
+
 bool
 AlgebraicOpt::visit(BasicBlock *bb)
 {
@@ -2019,6 +2044,9 @@ AlgebraicOpt::visit(BasicBlock *bb)
       case OP_SUCLAMP:
          handleSUCLAMP(i);
          break;
+      case OP_NEG:
+         handleNEG(i);
+         break;
       default:
          break;
       }
-- 
2.7.0