MIPS: [turbofan] Optimize Float32 to Int32 rep. changes with Float32 round ops.

src/compiler/mips/instruction-selector-mips.cc

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index e3981a2bd6a6e1a3e3a62c6fe97838251e5a79c4..bdde19c37083158deb0909edad780caf4b07b03f 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -535,8 +535,40 @@ void InstructionSelector::VisitChangeFloat64ToInt32(Node* node) {
              g.UseRegister(value->InputAt(0)));
         return;
       default:
-        VisitRR(this, kMipsTruncWD, node);
+        break;
+    }
+    if (value->opcode() == IrOpcode::kChangeFloat32ToFloat64) {
+      Node* next = value->InputAt(0);
+      if (CanCover(value, next)) {
+        // Match ChangeFloat64ToInt32(ChangeFloat32ToFloat64(Float64Round##OP))
+        switch (next->opcode()) {
+          case IrOpcode::kFloat32RoundDown:
+            Emit(kMipsFloorWS, g.DefineAsRegister(node),
+                 g.UseRegister(next->InputAt(0)));
+            return;
+          case IrOpcode::kFloat32RoundUp:
+            Emit(kMipsCeilWS, g.DefineAsRegister(node),
+                 g.UseRegister(next->InputAt(0)));
+            return;
+          case IrOpcode::kFloat32RoundTiesEven:
+            Emit(kMipsRoundWS, g.DefineAsRegister(node),
+                 g.UseRegister(next->InputAt(0)));
+            return;
+          case IrOpcode::kFloat32RoundTruncate:
+            Emit(kMipsTruncWS, g.DefineAsRegister(node),
+                 g.UseRegister(next->InputAt(0)));
+            return;
+          default:
+            Emit(kMipsTruncWS, g.DefineAsRegister(node),
+                 g.UseRegister(value->InputAt(0)));
+            return;
+        }
+      } else {
+        // Match float32 -> float64 -> int32 representation change path.
+        Emit(kMipsTruncWS, g.DefineAsRegister(node),
+             g.UseRegister(value->InputAt(0)));
         return;
+      }
     }
   }
   VisitRR(this, kMipsTruncWD, node);
@@ -549,6 +581,16 @@ void InstructionSelector::VisitChangeFloat64ToUint32(Node* node) {
 
 
 void InstructionSelector::VisitTruncateFloat64ToFloat32(Node* node) {
+  MipsOperandGenerator g(this);
+  Node* value = node->InputAt(0);
+  // Match TruncateFloat64ToFloat32(ChangeInt32ToFloat64) to corresponding
+  // instruction.
+  if (CanCover(node, value) &&
+      value->opcode() == IrOpcode::kChangeInt32ToFloat64) {
+    Emit(kMipsCvtSW, g.DefineAsRegister(node),
+         g.UseRegister(value->InputAt(0)));
+    return;
+  }
   VisitRR(this, kMipsCvtSD, node);
 }