Add atomic multiply and divide operations, built on top of CompareAndSwap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74004 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 20 insertions, 0 deletions

diff --git a/include/llvm/System/Atomic.h b/include/llvm/System/Atomic.h
index c4049d40da..4ec117be29 100644
--- a/include/llvm/System/Atomic.h
+++ b/include/llvm/System/Atomic.h
@@ -27,6 +27,8 @@ namespace llvm {
     cas_flag AtomicIncrement(volatile cas_flag* ptr);
     cas_flag AtomicDecrement(volatile cas_flag* ptr);
     cas_flag AtomicAdd(volatile cas_flag* ptr, cas_flag val);
+    cas_flag AtomicMul(volatile cas_flag* ptr, cas_flag val);
+    cas_flag AtomicDiv(volatile cas_flag* ptr, cas_flag val);
   }
 }
 
diff --git a/lib/System/Atomic.cpp b/lib/System/Atomic.cpp
index 6e751a30d4..f9b55a186d 100644
--- a/lib/System/Atomic.cpp
+++ b/lib/System/Atomic.cpp
@@ -91,4 +91,22 @@ sys::cas_flag sys::AtomicAdd(volatile sys::cas_flag* ptr, sys::cas_flag val) {
 #endif
 }
 
+sys::cas_flag sys::AtomicMul(volatile sys::cas_flag* ptr, sys::cas_flag val) {
+  sys::cas_flag original, result;
+  do {
+    original = *ptr;
+    result = original * val;
+  } while (sys::CompareAndSwap(ptr, result, original) != original);
 
+  return result;
+}
+
+sys::cas_flag sys::AtomicDiv(volatile sys::cas_flag* ptr, sys::cas_flag val) {
+  sys::cas_flag original, result;
+  do {
+    original = *ptr;
+    result = original / val;
+  } while (sys::CompareAndSwap(ptr, result, original) != original);
+
+  return result;
+}