Memory Dependence Analysis (not mem-dep test) take advantage of "invariant.load" metadata.
The "invariant.load" metadata indicates the memory unit being accessed is immutable.
A load annotated with this metadata can be moved across any store.
As I am not sure if it is legal to move such loads across barrier/fence, this
change dose not allow such transformation.
rdar://11311484
Thank Arnold for code review.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176562 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/LLVMContext.cpp b/lib/IR/LLVMContext.cpp
index b73cd03..883bb98 100644
--- a/lib/IR/LLVMContext.cpp
+++ b/lib/IR/LLVMContext.cpp
@@ -58,6 +58,11 @@
unsigned TBAAStructID = getMDKindID("tbaa.struct");
assert(TBAAStructID == MD_tbaa_struct && "tbaa.struct kind id drifted");
(void)TBAAStructID;
+
+ // Create the 'invariant.load' metadata kind.
+ unsigned InvariantLdId = getMDKindID("invariant.load");
+ assert(InvariantLdId == MD_invariant_load && "invariant.load kind id drifted");
+ (void)InvariantLdId;
}
LLVMContext::~LLVMContext() { delete pImpl; }