Cache the results of slow math operations on machines that don't...

src/heap.cc

Index: src/heap.cc
===================================================================
--- src/heap.cc	(revision 2785)
+++ src/heap.cc	(working copy)
@@ -257,6 +257,7 @@
 
 
 void Heap::GarbageCollectionPrologue() {
+  TranscendentalCache::Clear();
   gc_count_++;
 #ifdef DEBUG
   ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
@@ -3986,4 +3987,30 @@
 }
 #endif
 
+
+TranscendentalCache::TranscendentalCache(TranscendentalCache::Type t)
+  : type_(t) {
+  uint32_t in0 = 0xffffffffu;  // Bit-pattern for a NaN that isn't
+  uint32_t in1 = 0xffffffffu;  // generated by the FPU.
+  for (int i = 0; i < kCacheSize; i++) {

[Søren Thygesen Gjesse, 2009/09/01 08:40:31]

Would memcpy be faster here?

[Erik Corry, 2009/09/01 09:02:28]

Possibly, but I don't expect this function to be called all that often, and it
would look messier.

+    elements_[i].in[0] = in0;
+    elements_[i].in[1] = in1;
+    elements_[i].output = NULL;
+  }
+}
+
+
+TranscendentalCache* TranscendentalCache::caches_[kNumberOfCaches];
+
+
+void TranscendentalCache::Clear() {
+  for (int i = 0; i < kNumberOfCaches; i++) {
+    if (caches_[i] != NULL) {
+      delete caches_[i];
+      caches_[i] = NULL;
+    }
+  }
+}
+
+
 } }  // namespace v8::internal