Add comments about DstAlign and SrcAlign.

llvm-svn: 100132

2 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index d043ec626a2..e67666d8048 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -5539,6 +5539,13 @@ PPCTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
   return false;
 }
 
+/// getOptimalMemOpType - Returns the target specific optimal type for load
+/// and store operations as a result of memset, memcpy, and memmove lowering.
+/// If DstAlign is zero that means it's safe to destination alignment can
+/// satisfy any constraint. Similarly if SrcAlign is zero it means there
+/// isn't a need to check it against alignment requirement, probably because
+/// the source does not need to be loaded. It returns EVT::Other if
+/// SelectionDAG should be responsible for determining it.
 EVT PPCTargetLowering::getOptimalMemOpType(uint64_t Size,
                                            unsigned DstAlign, unsigned SrcAlign,
                                            bool SafeToUseFP,
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index bb2d84ece54..19fefab2d3a 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -347,6 +347,13 @@ namespace llvm {
 
     virtual bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const;
     
+    /// getOptimalMemOpType - Returns the target specific optimal type for load
+    /// and store operations as a result of memset, memcpy, and memmove lowering.
+    /// If DstAlign is zero that means it's safe to destination alignment can
+    /// satisfy any constraint. Similarly if SrcAlign is zero it means there
+    /// isn't a need to check it against alignment requirement, probably because
+    /// the source does not need to be loaded. It returns EVT::Other if
+    /// SelectionDAG should be responsible for determining it.
     virtual EVT getOptimalMemOpType(uint64_t Size,
                                     unsigned DstAlign, unsigned SrcAlign,
                                     bool SafeToUseFP, SelectionDAG &DAG) const;