[GISel][NFC]: Add methods to speed up insertion into GISelWorklist

https://reviews.llvm.org/D58073

Speed up insertion during the initial populating phase into the
GISelWorkList by deferring repeatedly resizing the DenseMap.
This results in ~10% improvement in the combiner passes, and
~3% speedup in the Legalizer.

reviewed by: aemerson.

llvm-svn: 354093

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/Combiner.cpp b/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
index 093702bd45d..31cb1dbbc9b 100644
--- a/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Combiner.cpp
@@ -129,9 +129,10 @@ bool Combiner::combineMachineInstrs(MachineFunction &MF,
           CurMI->eraseFromParentAndMarkDBGValuesForRemoval();
           continue;
         }
-        WorkList.insert(CurMI);
+        WorkList.deferred_insert(CurMI);
       }
     }
+    WorkList.finalize();
     // Main Loop. Process the instructions here.
     while (!WorkList.empty()) {
       MachineInstr *CurrInst = WorkList.pop_back_val();