comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145422 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/Target/ARM/ARMHazardRecognizer.h b/lib/Target/ARM/ARMHazardRecognizer.h
index 2bc218d856..053f874e1b 100644
--- a/lib/Target/ARM/ARMHazardRecognizer.h
+++ b/lib/Target/ARM/ARMHazardRecognizer.h
@@ -23,6 +23,10 @@ class ARMBaseRegisterInfo;
 class ARMSubtarget;
 class MachineInstr;
 
+/// ARMHazardRecognizer handles special constraints that are not expressed in
+/// the scheduling itinerary. This is only used during postRA scheduling. The
+/// ARM preRA scheduler uses an unspecialized instance of the
+/// ScoreboardHazardRecognizer.
 class ARMHazardRecognizer : public ScoreboardHazardRecognizer {
   const ARMBaseInstrInfo &TII;
   const ARMBaseRegisterInfo &TRI;