Fix non-determinism in DAGISel emitter.

 - This manifested as non-determinism in the .inc output in rare cases (when two
   distinct patterns ended up being equivalent, which is rather rare). That
   meant the pattern matching was non-deterministic, which could eventually mean
   the code generator selected different instructions based on the arch.

 - It's probably worth making the DAGISel ensure a total ordering (or force the
   user to), but the simple fix here is to totally order the Record* maps based
   on a unique ID.

 - PR4672, PR4711.

Yay:
--
ddunbar@giles:~$ cat ~/llvm.obj.64/lib/Target/*/*.inc | shasum
d1099ff34b21459a5a3e7021c225c080e6017ece  -
ddunbar@giles:~$ cat ~/llvm.obj.ppc/lib/Target/*/*.inc | shasum
d1099ff34b21459a5a3e7021c225c080e6017ece  -
--

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79846 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 0 deletions

diff --git a/utils/TableGen/Record.cpp b/utils/TableGen/Record.cpp
index 8f31624644..d594c9aa09 100644
--- a/utils/TableGen/Record.cpp
+++ b/utils/TableGen/Record.cpp
@@ -1319,6 +1319,8 @@ void RecordVal::print(raw_ostream &OS, bool PrintSem) const {
   if (PrintSem) OS << ";\n";
 }
 
+unsigned Record::LastID = 0;
+
 void Record::setName(const std::string &Name) {
   if (Records.getDef(getName()) == this) {
     Records.removeDef(getName());