Vendor import of llvm trunk r130700:

http://llvm.org/svn/llvm-project/llvm/trunk@130700

1 files changed, 19 insertions, 0 deletions

diff --git a/include/llvm/Analysis/MemoryDependenceAnalysis.h b/include/llvm/Analysis/MemoryDependenceAnalysis.h
index 4d5dd19..b56fe08 100644
--- a/include/llvm/Analysis/MemoryDependenceAnalysis.h
+++ b/include/llvm/Analysis/MemoryDependenceAnalysis.h
@@ -48,6 +48,11 @@ namespace llvm {
       /// this occurs when we see a may-aliased store to the memory location we
       /// care about.
       ///
+      /// There are several cases that may be interesting here:
+      ///   1. Loads are clobbered by may-alias stores.
+      ///   2. Loads are considered clobbered by partially-aliased loads.  The
+      ///      client may choose to analyze deeper into these cases.
+      ///
       /// A dependence query on the first instruction of the entry block will
       /// return a clobber(self) result.
       Clobber,
@@ -350,6 +355,20 @@ namespace llvm {
                                           BasicBlock::iterator ScanIt,
                                           BasicBlock *BB);
     
+    
+    /// getLoadLoadClobberFullWidthSize - This is a little bit of analysis that
+    /// looks at a memory location for a load (specified by MemLocBase, Offs,
+    /// and Size) and compares it against a load.  If the specified load could
+    /// be safely widened to a larger integer load that is 1) still efficient,
+    /// 2) safe for the target, and 3) would provide the specified memory
+    /// location value, then this function returns the size in bytes of the
+    /// load width to use.  If not, this returns zero.
+    static unsigned getLoadLoadClobberFullWidthSize(const Value *MemLocBase,
+                                                    int64_t MemLocOffs,
+                                                    unsigned MemLocSize,
+                                                    const LoadInst *LI,
+                                                    const TargetData &TD);
+    
   private:
     MemDepResult getCallSiteDependencyFrom(CallSite C, bool isReadOnlyCall,
                                            BasicBlock::iterator ScanIt,