[TurboProp] Enable mid-tier register allocator for TurboProp

BUG=v8:9684

Change-Id: I064b552b021597a80e57303cab3c2fbf552be6a2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2463228
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70427}

src/codegen/optimized-compilation-info.h

@@ -149,6 +149,7 @@ class V8_EXPORT_PRIVATE OptimizedCompilationInfo final {
   bool IsNativeContextIndependent() const {
     return code_kind() == CodeKind::NATIVE_CONTEXT_INDEPENDENT;
   }
+  bool IsTurboprop() const { return code_kind() == CodeKind::TURBOPROP; }
   bool IsStub() const {
     return code_kind() == CodeKind::DEOPT_ENTRIES_OR_FOR_TESTING;
   }

src/compiler/pipeline.cc

@@ -3375,7 +3375,7 @@ bool PipelineImpl::SelectInstructions(Linkage* linkage) {
       config = RegisterConfiguration::Default();
     }
 
-    if (FLAG_turboprop_mid_tier_reg_alloc) {
+    if (data->info()->IsTurboprop() && FLAG_turboprop_mid_tier_reg_alloc) {
       AllocateRegistersForMidTier(config, call_descriptor, run_verifier);
     } else {
       AllocateRegistersForTopTier(config, call_descriptor, run_verifier);
@@ -3698,8 +3698,6 @@ void PipelineImpl::AllocateRegistersForMidTier(
   data->sequence()->ValidateDeferredBlockEntryPaths();
   data->sequence()->ValidateDeferredBlockExitPaths();
 #endif
-
-  if (info()->is_osr()) data->osr_helper()->SetupFrame(data->frame());
   data->InitializeMidTierRegisterAllocationData(config, call_descriptor);
 
   TraceSequence(info(), data, "before register allocation");

src/flags/flag-definitions.h

@@ -549,8 +549,8 @@ DEFINE_BOOL(trace_generalization, false, "trace map generalization")
 
 // Flags for TurboProp.
 DEFINE_BOOL(turboprop, false, "enable experimental turboprop mid-tier compiler")
-DEFINE_BOOL(turboprop_mid_tier_reg_alloc, false,
-            "enable experimental mid-tier register allocator")
+DEFINE_BOOL(turboprop_mid_tier_reg_alloc, true,
+            "enable mid-tier register allocator for turboprop")
 DEFINE_NEG_IMPLICATION(turboprop, turbo_inlining)
 DEFINE_IMPLICATION(turboprop, concurrent_inlining)
 DEFINE_VALUE_IMPLICATION(turboprop, interrupt_budget, 15 * KB)