[SelectionDAG] Avoid repeated hash lookups (NFC)

[kazutakahirata]

No description provided.

[llvmbot]

@llvm/pr-subscribers-llvm-selectiondag

Author: Kazu Hirata (kazutakahirata)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/131266.diff

1 Files Affected:

• (modified) llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp (+3-2)

diff --git a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
index 987ea826f782e..735dcef8c28bf 100644
--- a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
@@ -889,7 +889,8 @@ SDValue SelectionDAGBuilder::LowerAsSTATEPOINT(
     }
 
     // Handle multiple gc.relocates of the same input efficiently.
-    if (VirtRegs.count(SD))
+    auto [VRegIt, Inserted] = VirtRegs.try_emplace(SD);
+    if (!Inserted)
       continue;
 
     auto *RetTy = Relocate->getType();
@@ -900,7 +901,7 @@ SDValue SelectionDAGBuilder::LowerAsSTATEPOINT(
     RFV.getCopyToRegs(Relocated, DAG, getCurSDLoc(), Chain, nullptr);
     PendingExports.push_back(Chain);
 
-    VirtRegs[SD] = Reg;
+    VRegIt->second = Reg;
   }
 
   // Record for later use how each relocation was lowered.  This is needed to