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

diff --git a/utils/TableGen/CodeGenDAGPatterns.cpp b/utils/TableGen/CodeGenDAGPatterns.cpp
index 2f12a6c4cbee285c9c5c3ef190565d1b9cab4f86..f0a8c4d74ff1b588ca389df6f97c98f27b9cb1e6 100644 (file)
--- a/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -100,6 +100,9 @@ bool isExtVectorInVTs(const std::vector<unsigned char> &EVTs) {
 } // end namespace EEVT.
 } // end namespace llvm.
 
+bool RecordPtrCmp::operator()(const Record *LHS, const Record *RHS) const {
+  return LHS->getID() < RHS->getID();
+}
 
 /// Dependent variable map for CodeGenDAGPattern variant generation
 typedef std::map<std::string, int> DepVarMap;

diff --git a/utils/TableGen/CodeGenDAGPatterns.h b/utils/TableGen/CodeGenDAGPatterns.h
index 56dcfcff9102fc33cdea1385ae1e82386c4e0820..f7198d8ae5b19c28f7671738ca15c2fb2f2fca3b 100644 (file)
--- a/utils/TableGen/CodeGenDAGPatterns.h
+++ b/utils/TableGen/CodeGenDAGPatterns.h
@@ -462,6 +462,10 @@ struct PatternToMatch {
   std::string getPredicateCheck() const;
 };
 
+// Deterministic comparison of Record*.
+struct RecordPtrCmp {
+  bool operator()(const Record *LHS, const Record *RHS) const;
+};
   
 class CodeGenDAGPatterns {
   RecordKeeper &Records;
@@ -469,12 +473,12 @@ class CodeGenDAGPatterns {
   std::vector<CodeGenIntrinsic> Intrinsics;
   std::vector<CodeGenIntrinsic> TgtIntrinsics;
   
-  std::map<Record*, SDNodeInfo> SDNodes;
-  std::map<Record*, std::pair<Record*, std::string> > SDNodeXForms;
-  std::map<Record*, ComplexPattern> ComplexPatterns;
-  std::map<Record*, TreePattern*> PatternFragments;
-  std::map<Record*, DAGDefaultOperand> DefaultOperands;
-  std::map<Record*, DAGInstruction> Instructions;
+  std::map<Record*, SDNodeInfo, RecordPtrCmp> SDNodes;
+  std::map<Record*, std::pair<Record*, std::string>, RecordPtrCmp> SDNodeXForms;
+  std::map<Record*, ComplexPattern, RecordPtrCmp> ComplexPatterns;
+  std::map<Record*, TreePattern*, RecordPtrCmp> PatternFragments;
+  std::map<Record*, DAGDefaultOperand, RecordPtrCmp> DefaultOperands;
+  std::map<Record*, DAGInstruction, RecordPtrCmp> Instructions;
   
   // Specific SDNode definitions:
   Record *intrinsic_void_sdnode;

diff --git a/utils/TableGen/Record.cpp b/utils/TableGen/Record.cpp
index 8f31624644f62ca69fcda60be469e8a7300200fa..d594c9aa09aad70298b4f1ea44a78e9ad049537e 100644 (file)
--- 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());

diff --git a/utils/TableGen/Record.h b/utils/TableGen/Record.h
index 40c8239b9a32fd80b0b8cfd841500f8f97f084dd..9415109dbb3b3095d632870fddaff2474d3e3013 100644 (file)
--- a/utils/TableGen/Record.h
+++ b/utils/TableGen/Record.h
@@ -1220,6 +1220,10 @@ inline raw_ostream &operator<<(raw_ostream &OS, const RecordVal &RV) {
 }
 
 class Record {
+  static unsigned LastID;
+
+  // Unique record ID.
+  unsigned ID;
   std::string Name;
   SMLoc Loc;
   std::vector<std::string> TemplateArgs;
@@ -1227,9 +1231,12 @@ class Record {
   std::vector<Record*> SuperClasses;
 public:
 
-  explicit Record(const std::string &N, SMLoc loc) : Name(N), Loc(loc) {}
+  explicit Record(const std::string &N, SMLoc loc) : 
+    ID(LastID++), Name(N), Loc(loc) {}
   ~Record() {}
   
+  unsigned getID() const { return ID; }
+
   const std::string &getName() const { return Name; }
   void setName(const std::string &Name);  // Also updates RecordKeeper.