Speed up addRegisterDead by adding more fast checks before performing the expensive

subregister query, and by increasing the size of the subregister hashtable so
that there are fewer collisions.

llvm-svn: 54781

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index c952293976e..d602e2442f7 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -834,7 +834,9 @@ bool MachineInstr::addRegisterDead(unsigned IncomingReg,
       // There exists a super-register that's marked dead.
       if (RegInfo->isSuperRegister(IncomingReg, Reg))
         return true;
-      if (RegInfo->isSubRegister(IncomingReg, Reg))
+      if (RegInfo->getSubRegisters(IncomingReg) &&
+          RegInfo->getSuperRegisters(Reg) &&
+          RegInfo->isSubRegister(IncomingReg, Reg))
         DeadOps.push_back(i);
     }
   }