Add new "memory use marker" intrinsics. These indicate lifetimes and invariant

sections of memory objects.

llvm-svn: 83953

1 files changed, 36 insertions, 0 deletions

diff --git a/llvm/test/Feature/memorymarkers.ll b/llvm/test/Feature/memorymarkers.ll
new file mode 100644
index 00000000000..06b8376678f
--- /dev/null
+++ b/llvm/test/Feature/memorymarkers.ll
@@ -0,0 +1,36 @@
+; RUN: llvm-as -disable-output < %s
+
+%"struct.std::pair<int,int>" = type { i32, i32 }
+
+declare void @_Z3barRKi(i32*)
+
+declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind
+declare {}* @llvm.invariant.start(i64, i8* nocapture) readonly nounwind
+declare void @llvm.invariant.end({}*, i64, i8* nocapture) nounwind
+
+define i32 @_Z4foo2v() nounwind {
+entry:
+  %x = alloca %"struct.std::pair<int,int>"
+  %y = bitcast %"struct.std::pair<int,int>"* %x to i8*
+
+  ;; Constructor starts here (this isn't needed since it is immediately
+  ;; preceded by an alloca, but shown for completeness).
+  call void @llvm.lifetime.start(i64 8, i8* %y)
+
+  %0 = getelementptr %"struct.std::pair<int,int>"* %x, i32 0, i32 0
+  store i32 4, i32* %0, align 8
+  %1 = getelementptr %"struct.std::pair<int,int>"* %x, i32 0, i32 1
+  store i32 5, i32* %1, align 4
+
+  ;; Constructor has finished here.
+  %inv = call {}* @llvm.invariant.start(i64 8, i8* %y)
+  call void @_Z3barRKi(i32* %0) nounwind
+  %2 = load i32* %0, align 8
+
+  ;; Destructor is run here.
+  call void @llvm.invariant.end({}* %inv, i64 8, i8* %y)
+  ;; Destructor is done here.
+  call void @llvm.lifetime.end(i64 8, i8* %y)
+  ret i32 %2
+}