MIsched machine model: tablegen subtarget emitter improvement.

Fix the way resources are counted. I'm taking some time to cleanup the
way MachineScheduler handles in-order machine resources. Eventually
we'll need more PPC/Atom test cases in tree.

llvm-svn: 176390

1 files changed, 14 insertions, 1 deletions

diff --git a/llvm/utils/TableGen/SubtargetEmitter.cpp b/llvm/utils/TableGen/SubtargetEmitter.cpp
index fc8d00dd83f..93eef868ea0 100644
--- a/llvm/utils/TableGen/SubtargetEmitter.cpp
+++ b/llvm/utils/TableGen/SubtargetEmitter.cpp
@@ -893,7 +893,20 @@ void SubtargetEmitter::GenSchedClassTables(const CodeGenProcModel &ProcModel,
             WPREntry.Cycles = Cycles[PRIdx];
           else
             WPREntry.Cycles = 1;
-          WriteProcResources.push_back(WPREntry);
+          // If this resource is already used in this sequence, add the current
+          // entry's cycles so that the same resource appears to be used
+          // serially, rather than multiple parallel uses. This is important for
+          // in-order machine where the resource consumption is a hazard.
+          unsigned WPRIdx = 0, WPREnd = WriteProcResources.size();
+          for( ; WPRIdx != WPREnd; ++WPRIdx) {
+            if (WriteProcResources[WPRIdx].ProcResourceIdx
+                == WPREntry.ProcResourceIdx) {
+              WriteProcResources[WPRIdx].Cycles += WPREntry.Cycles;
+              break;
+            }
+          }
+          if (WPRIdx == WPREnd)
+            WriteProcResources.push_back(WPREntry);
         }
       }
       WriteLatencies.push_back(WLEntry);