[XLA:CPU] Make loop unrolling on by default in IrCompiler.

Reverts 6ae9c29

PiperOrigin-RevId: 723688407

Author: WillFroom

third_party/xla/xla/backends/cpu/codegen/ir_compiler.cc

@@ -109,7 +109,7 @@ llvm::Expected<std::unique_ptr<llvm::MemoryBuffer>> IrCompiler::operator()(
   pto.LoopVectorization = !options_.optimize_for_size;
   pto.SLPVectorization =
       !options_.optimize_for_size && !options_.disable_slp_vectorizer;
-  pto.LoopUnrolling = options_.enable_loop_unrolling;
+  pto.LoopUnrolling = !options_.disable_loop_unrolling;
 
   llvm::LoopAnalysisManager lam;
   llvm::FunctionAnalysisManager fam;

third_party/xla/xla/backends/cpu/codegen/ir_compiler.h

@@ -61,7 +61,7 @@ class IrCompiler : public llvm::orc::IRCompileLayer::IRCompiler {
     bool disable_expensive_passes = false;
     bool disable_slp_vectorizer = false;
 
-    bool enable_loop_unrolling = false;
+    bool disable_loop_unrolling = false;
 
     bool dfsan_enabled = false;
     std::vector<std::string> dfsan_abi_list_files;

third_party/xla/xla/backends/cpu/testlib/kernel_runner.cc

@@ -104,7 +104,7 @@ absl::StatusOr<JitCompiler> KernelRunner::CreateJitCompiler(
       /*disable_expensive_passes=*/
       debug_options.xla_llvm_disable_expensive_passes(),
       /*slp_vectorizer_disabled=*/options::SlpVectorizerDisabled(config),
-      /*enable_loop_unrolling=*/options::EnableLoopUnrolling(config),
+      /*disable_loop_unrolling=*/options::DisableLoopUnrolling(config),
   };
 
   IrCompiler::CompilationHooks ir_compiler_hooks;

third_party/xla/xla/service/cpu/cpu_compiler.cc

@@ -1362,7 +1362,7 @@ CpuCompiler::CompileCpuExecutable(std::unique_ptr<HloModule> module) {
       /*disable_expensive_passes=*/
       debug_options.xla_llvm_disable_expensive_passes(),
       /*slp_vectorizer_disabled=*/options::SlpVectorizerDisabled(config),
-      /*enable_loop_unrolling=*/options::EnableLoopUnrolling(config),
+      /*disable_loop_unrolling=*/options::DisableLoopUnrolling(config),
   };
 
   // Compiler hooks to intercept compiled LLVM IR modules.
@@ -1964,8 +1964,8 @@ CpuCompiler::CompileAheadOfTime(std::unique_ptr<HloModuleGroup> module_group,
           module->config().debug_options().xla_llvm_disable_expensive_passes(),
           /*disable_slp_vectorizer=*/
           options::SlpVectorizerDisabled(module->config()),
-          /*enable_loop_unrolling=*/
-          options::EnableLoopUnrolling(module->config()),
+          /*disable_loop_unrolling=*/
+          options::DisableLoopUnrolling(module->config()),
           /*dfsan_enabled=*/aot_options.sanitize_dataflow(),
           /*dfsan_abilists_enabled=*/aot_options.sanitize_abilists_dataflow()};
 

third_party/xla/xla/service/cpu/cpu_options.cc

@@ -35,7 +35,7 @@ const char* const kXlaForceEnableExperimentalLlvmIrGemm =
     "xla_force_enable_experimental_llvm_ir_gemm";
 const char* const kLlvmIrGemmTileSize = "xla_llvm_ir_gemm_tile_size";
 const char* const kDisableSlpVectorizer = "xla_cpu_disable_slp_vectorizer";
-const char* const kEnableLoopUnrolling = "xla_cpu_enable_loop_unrolling";
+const char* const kDisableLoopUnrolling = "xla_cpu_disable_loop_unrolling";
 
 }  // namespace
 
@@ -61,10 +61,10 @@ bool SlpVectorizerDisabled(const HloModuleConfig& config) {
   return extra_options_map.count(kDisableSlpVectorizer) > 0;
 }
 
-bool EnableLoopUnrolling(const HloModuleConfig& config) {
+bool DisableLoopUnrolling(const HloModuleConfig& config) {
   const auto& extra_options_map =
       config.debug_options().xla_backend_extra_options();
-  return extra_options_map.count(kEnableLoopUnrolling) > 0;
+  return extra_options_map.count(kDisableLoopUnrolling) > 0;
 }
 
 std::optional<int64_t> LlvmIrGemvTilingFactor(const HloModuleConfig& config) {

third_party/xla/xla/service/cpu/cpu_options.h

@@ -32,7 +32,7 @@ namespace options {
 bool OptimizeForSizeRequested(const HloModuleConfig& config);
 bool VectorizedReduceDisabled(const HloModuleConfig& config);
 bool SlpVectorizerDisabled(const HloModuleConfig& config);
-bool EnableLoopUnrolling(const HloModuleConfig& config);
+bool DisableLoopUnrolling(const HloModuleConfig& config);
 bool ForceEnableExperimentalLlvmIrGemm(const HloModuleConfig& config);
 std::optional<int64_t> LlvmIrGemvTilingFactor(const HloModuleConfig& config);
 std::optional<std::tuple<int64_t, int64_t, int64_t>> LlvmIrGemmTileSize(