[MIR-Canon] Fixing non-determinism that was breaking bots (NFC).

An earlier fix of a subtle iterator invalidation bug had uncovered a
nondeterminism that was present in the MultiUsers bag. Problem was that
MultiUsers was being looked up using pointers.

This patch is an NFC change that numbers each multiuser and processes each in
numbered order. This fixes the test failure on netbsd and will likely fix the
green-dragon bot too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363012 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/MIRCanonicalizerPass.cpp b/lib/CodeGen/MIRCanonicalizerPass.cpp
index c7d1131d7b8a453b84ddad3145e167cd1f550370..f49bc854e23f591398c42e3c04776d80de232d71 100644 (file)
--- a/lib/CodeGen/MIRCanonicalizerPass.cpp
+++ b/lib/CodeGen/MIRCanonicalizerPass.cpp
@@ -180,6 +180,8 @@ static bool rescheduleCanonically(unsigned &PseudoIdempotentInstCount,
   }
 
   std::map<MachineInstr *, std::vector<MachineInstr *>> MultiUsers;
+  std::map<unsigned, MachineInstr *> MultiUserLookup;
+  unsigned UseToBringDefCloserToCount = 0;
   std::vector<MachineInstr *> PseudoIdempotentInstructions;
   std::vector<unsigned> PhysRegDefs;
   for (auto *II : Instructions) {
@@ -255,6 +257,7 @@ static bool rescheduleCanonically(unsigned &PseudoIdempotentInstCount,
       if (Delta < Distance) {
         Distance = Delta;
         UseToBringDefCloserTo = UseInst;
+        MultiUserLookup[UseToBringDefCloserToCount++] = UseToBringDefCloserTo;
       }
     }
 
@@ -294,11 +297,11 @@ static bool rescheduleCanonically(unsigned &PseudoIdempotentInstCount,
   }
 
   // Sort the defs for users of multiple defs lexographically.
-  for (const auto &E : MultiUsers) {
+  for (const auto &E : MultiUserLookup) {
 
     auto UseI =
         std::find_if(MBB->instr_begin(), MBB->instr_end(),
-                     [&](MachineInstr &MI) -> bool { return &MI == E.first; });
+                     [&](MachineInstr &MI) -> bool { return &MI == E.second; });
 
     if (UseI == MBB->instr_end())
       continue;
@@ -306,7 +309,8 @@ static bool rescheduleCanonically(unsigned &PseudoIdempotentInstCount,
     LLVM_DEBUG(
         dbgs() << "Rescheduling Multi-Use Instructions Lexographically.";);
     Changed |= rescheduleLexographically(
-        E.second, MBB, [&]() -> MachineBasicBlock::iterator { return UseI; });
+        MultiUsers[E.second], MBB,
+        [&]() -> MachineBasicBlock::iterator { return UseI; });
   }
 
   PseudoIdempotentInstCount = PseudoIdempotentInstructions.size();