MIsched: add an ILP window property to machine model.

This was an experimental option, but needs to be defined
per-target. e.g. PPC A2 needs to aggressively hide latency.

I converted some in-order scheduling tests to A2. Hal is working on
more test cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171946 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/Target/X86/X86Schedule.td b/lib/Target/X86/X86Schedule.td
index c14407f..d99d085 100644
--- a/lib/Target/X86/X86Schedule.td
+++ b/lib/Target/X86/X86Schedule.td
@@ -470,12 +470,17 @@ def IIC_NOP : InstrItinClass;
 // latencies. Since these latencies are not used for pipeline hazards,
 // they do not need to be exact.
 //
+// ILPWindow=10 is an arbitrary threshold that approximates cycles of
+// latency hidden by instruction buffers. The actual value is not very
+// important but should be zero for inorder and nonzero for OOO processors.
+//
 // The GenericModel contains no instruciton itineraries.
 def GenericModel : SchedMachineModel {
   let IssueWidth = 4;
   let MinLatency = 0;
   let LoadLatency = 4;
   let HighLatency = 10;
+  let ILPWindow = 10;
 }
 
 include "X86ScheduleAtom.td"