[fpu] Ensure FPU state is consistent for code cache

LeszekSwirski · V8 LUCI CQ · commit 7e9d59456d74 · 2025-06-23T07:58:42.000-07:00
Add FPU state to the code cache hash, and ensure deserialization threads preserve it. Fixed: 425703809 Change-Id: Id89613685536a04d28389b95b342fac14ba296a1 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6658269 Reviewed-by: Jakob Kummerow <jkummerow@chromium.org> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org> Auto-Submit: Leszek Swirski <leszeks@chromium.org> Cr-Commit-Position: refs/heads/main@{#100966}
diff --git a/src/codegen/compiler.cc b/src/codegen/compiler.cc
@@ -2757,6 +2757,9 @@ BackgroundDeserializeTask::BackgroundDeserializeTask(
 }
 
 void BackgroundDeserializeTask::Run() {
+  base::FlushDenormalsScope flush_denormals_scope(
+      isolate_for_local_isolate_->flush_denormals());
+
   TimedHistogramScope timer(timer_, nullptr, &background_time_in_microseconds_);
   LocalIsolate isolate(isolate_for_local_isolate_, ThreadKind::kBackground);
   UnparkedScope unparked_scope(&isolate);
@@ -2791,6 +2794,9 @@ bool BackgroundDeserializeTask::ShouldMergeWithExistingScript() const {
 void BackgroundDeserializeTask::MergeWithExistingScript() {
   DCHECK(ShouldMergeWithExistingScript());
 
+  base::FlushDenormalsScope flush_denormals_scope(
+      isolate_for_local_isolate_->flush_denormals());
+
   LocalIsolate isolate(isolate_for_local_isolate_, ThreadKind::kBackground);
   UnparkedScope unparked_scope(&isolate);
   LocalHandleScope handle_scope(isolate.heap());
diff --git a/src/flags/flags.cc b/src/flags/flags.cc
@@ -16,6 +16,7 @@
 #include <set>
 #include <sstream>
 
+#include "src/base/fpu.h"
 #include "src/base/hashing.h"
 #include "src/base/lazy-instance.h"
 #include "src/base/platform/platform.h"
@@ -450,6 +451,9 @@ uint32_t ComputeFlagListHash() {
   std::ostringstream modified_args_as_string;
   if (COMPRESS_POINTERS_BOOL) modified_args_as_string << "ptr-compr";
   if (DEBUG_BOOL) modified_args_as_string << "debug";
+  if (base::FPU::GetFlushDenormals()) {
+    modified_args_as_string << "flush-denormals";
+  }
 
 #ifdef DEBUG
   // These two sets are used to check that we don't leave out any flags
