Add flags to indicate that there are "never" side effects or that there "may be"

side effects for machine instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45022 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/Target/Target.td b/lib/Target/Target.td
index 4c278bb8bd..9619cb98f9 100644
--- a/lib/Target/Target.td
+++ b/lib/Target/Target.td
@@ -203,6 +203,11 @@ class Instruction {
   bit usesCustomDAGSchedInserter = 0; // Pseudo instr needing special help.
   bit hasCtrlDep   = 0;     // Does this instruction r/w ctrl-flow chains?
   bit isNotDuplicable = 0;  // Is it unsafe to duplicate this instruction?
+
+  // Side effect flags - If neither of these flags is set, then the instruction
+  // *always* has side effects. Otherwise, it's one or the other.
+  bit mayHaveSideEffects = 0;  // This instruction *may* have side effects.
+  bit neverHasSideEffects = 0; // This instruction never has side effects.
   
   InstrItinClass Itinerary = NoItinerary;// Execution steps used for scheduling.