Various comment fixes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78139 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index 7717fc8..d158c48 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -7,7 +7,12 @@
//
//===----------------------------------------------------------------------===//
//
-// This pass
+// This pass moves instructions into successor blocks, when possible, so that
+// they aren't executed on paths where their results aren't needed.
+//
+// This pass is not intended to be a replacement or a complete alternative
+// for an LLVM-IR-level sinking pass. It is only designed to sink simple
+// constructs that are not exposed before lowering and instruction selection.
//
//===----------------------------------------------------------------------===//
@@ -31,7 +36,7 @@
const TargetInstrInfo *TII;
MachineFunction *CurMF; // Current MachineFunction
MachineRegisterInfo *RegInfo; // Machine register information
- MachineDominatorTree *DT; // Machine dominator tree for the current Loop
+ MachineDominatorTree *DT; // Machine dominator tree
public:
static char ID; // Pass identification
@@ -152,7 +157,7 @@
// also sink them down before their first use in the block. This xform has to
// be careful not to *increase* register pressure though, e.g. sinking
// "x = y + z" down if it kills y and z would increase the live ranges of y
- // and z only the shrink the live range of x.
+ // and z and only shrink the live range of x.
// Loop over all the operands of the specified instruction. If there is
// anything we can't handle, bail out.