Improve tablegen gen-subtarget diagnostics for missing machine models.

-debug-only=subtarget-emitter prints a lot of machine model diagnostics.
This prunes the output so that the "No machine model for XXX on processor YYY"
only appears when there is definitely no machine model for that opcode.
Previously it was printing that error even if the opcode was covered by
a more general scheduling class.

<rdar://problem/15919845> [TableGen][CodeGenSchedule] Debug output does not help spotting the missing scheduling classes

llvm-svn: 284452

1 files changed, 8 insertions, 5 deletions

diff --git a/llvm/utils/TableGen/CodeGenSchedule.cpp b/llvm/utils/TableGen/CodeGenSchedule.cpp
index 22f48ad3d48..eb7899ea92c 100644
--- a/llvm/utils/TableGen/CodeGenSchedule.cpp
+++ b/llvm/utils/TableGen/CodeGenSchedule.cpp
@@ -573,11 +573,14 @@ void CodeGenSchedModels::collectSchedClasses() {
         dbgs() << " " << SchedReads[*RI].Name;
       dbgs() << '\n';
     }
-    for (std::vector<CodeGenProcModel>::iterator PI = ProcModels.begin(),
-           PE = ProcModels.end(); PI != PE; ++PI) {
-      if (!std::count(ProcIndices.begin(), ProcIndices.end(), PI->Index))
-        dbgs() << "No machine model for " << Inst->TheDef->getName()
-               << " on processor " << PI->ModelName << '\n';
+    // If ProcIndices contains zero, the class applies to all processors.
+    if (!std::count(ProcIndices.begin(), ProcIndices.end(), 0)) {
+      for (std::vector<CodeGenProcModel>::iterator PI = ProcModels.begin(),
+             PE = ProcModels.end(); PI != PE; ++PI) {
+        if (!std::count(ProcIndices.begin(), ProcIndices.end(), PI->Index))
+          dbgs() << "No machine model for " << Inst->TheDef->getName()
+                 << " on processor " << PI->ModelName << '\n';
+      }
     }
   }
 }