[SchedModel] Remove instregex entries that don't match any instructions

This patch throws a fatal error if an instregex entry doesn't actually match any instructions. This is part of the work to reduce the compile time impact of increased instregex usage (PR35955), although the x86 models seem to be relatively clean.

All the cases I encountered have now been fixed in trunk and this will ensure they don't get reintroduced.

Differential Revision: https://reviews.llvm.org/D44687

llvm-svn: 328459

1 files changed, 11 insertions, 2 deletions

diff --git a/llvm/utils/TableGen/CodeGenSchedule.cpp b/llvm/utils/TableGen/CodeGenSchedule.cpp
index 9f9b32b424e..7791f4ac965 100644
--- a/llvm/utils/TableGen/CodeGenSchedule.cpp
+++ b/llvm/utils/TableGen/CodeGenSchedule.cpp
@@ -106,6 +106,8 @@ struct InstRegexOp : public SetTheory::Operator {
         Regexpr = Regex(pat);
       }
 
+      int NumMatches = 0;
+
       unsigned NumGeneric = Target.getNumFixedInstructions();
       ArrayRef<const CodeGenInstruction *> Generics =
           Target.getInstructionsByEnumValue().slice(0, NumGeneric + 1);
@@ -114,8 +116,10 @@ struct InstRegexOp : public SetTheory::Operator {
       for (auto *Inst : Generics) {
         StringRef InstName = Inst->TheDef->getName();
         if (InstName.startswith(Prefix) &&
-            (!Regexpr || Regexpr->match(InstName.substr(Prefix.size()))))
+            (!Regexpr || Regexpr->match(InstName.substr(Prefix.size())))) {
           Elts.insert(Inst->TheDef);
+          NumMatches++;
+        }
       }
 
       ArrayRef<const CodeGenInstruction *> Instructions =
@@ -139,9 +143,14 @@ struct InstRegexOp : public SetTheory::Operator {
       // a regex that needs to be checked.
       for (auto *Inst : make_range(Range)) {
         StringRef InstName = Inst->TheDef->getName();
-        if (!Regexpr || Regexpr->match(InstName.substr(Prefix.size())))
+        if (!Regexpr || Regexpr->match(InstName.substr(Prefix.size()))) {
           Elts.insert(Inst->TheDef);
+          NumMatches++;
+        }
       }
+
+      if (0 == NumMatches)
+        PrintFatalError(Loc, "instregex has no matches: " + Original);
     }
   }
 };