[turbofan] MIPS64: Faster checked ops for PoT arrays

src/compiler/mips64/instruction-selector-mips64.cc

Index: src/compiler/mips64/instruction-selector-mips64.cc
diff --git a/src/compiler/mips64/instruction-selector-mips64.cc b/src/compiler/mips64/instruction-selector-mips64.cc
index 8229ebc712ed6ffaeb987453c5bca08574d4d2a0..d48007b858e4fe13d326272be3c75a03be54b8e9 100644
--- a/src/compiler/mips64/instruction-selector-mips64.cc
+++ b/src/compiler/mips64/instruction-selector-mips64.cc
@@ -1854,6 +1854,15 @@ void InstructionSelector::VisitCheckedLoad(Node* node) {
                                                 : g.UseRegister(length)
                                           : g.UseRegister(length);
 
+  if (length->opcode() == IrOpcode::kInt32Constant) {
+    Int32Matcher m(length);
+    if (m.IsPowerOf2()) {
+      Emit(opcode, g.DefineAsRegister(node), offset_operand,
+           g.UseImmediate(length), g.UseRegister(buffer));
+      return;
+    }
+  }
+
   Emit(opcode | AddressingModeField::encode(kMode_MRI),
        g.DefineAsRegister(node), offset_operand, length_operand,
        g.UseRegister(buffer));
@@ -1906,6 +1915,15 @@ void InstructionSelector::VisitCheckedStore(Node* node) {
                                                 : g.UseRegister(length)
                                           : g.UseRegister(length);
 
+  if (length->opcode() == IrOpcode::kInt32Constant) {
+    Int32Matcher m(length);
+    if (m.IsPowerOf2()) {
+      Emit(opcode, g.NoOutput(), offset_operand, g.UseImmediate(length),
+           g.UseRegisterOrImmediateZero(value), g.UseRegister(buffer));
+      return;
+    }
+  }
+
   Emit(opcode | AddressingModeField::encode(kMode_MRI), g.NoOutput(),
        offset_operand, length_operand, g.UseRegisterOrImmediateZero(value),
        g.UseRegister(buffer));