[llvm] [CodeGen] Avoid repeated hash lookups (NFC) (PR #125463)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/125463

None

>From 3207a796155f435c81ce43c9ca122b0d23ef290a Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 2 Feb 2025 22:55:25 -0800
Subject: [PATCH] [CodeGen] Avoid repeated hash lookups (NFC)

---
 llvm/include/llvm/CodeGen/LiveIntervals.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/LiveIntervals.h b/llvm/include/llvm/CodeGen/LiveIntervals.h
index 540651ea114427..708917be497ef6 100644
--- a/llvm/include/llvm/CodeGen/LiveIntervals.h
+++ b/llvm/include/llvm/CodeGen/LiveIntervals.h
@@ -149,8 +149,9 @@ class LiveIntervals {
   LiveInterval &createEmptyInterval(Register Reg) {
     assert(!hasInterval(Reg) && "Interval already exists!");
     VirtRegIntervals.grow(Reg.id());
-    VirtRegIntervals[Reg.id()] = createInterval(Reg);
-    return *VirtRegIntervals[Reg.id()];
+    auto &Interval = VirtRegIntervals[Reg.id()];
+    Interval = createInterval(Reg);
+    return *Interval;
   }
 
   LiveInterval &createAndComputeVirtRegInterval(Register Reg) {
@@ -168,8 +169,9 @@ class LiveIntervals {
 
   /// Interval removal.
   void removeInterval(Register Reg) {
-    delete VirtRegIntervals[Reg];
-    VirtRegIntervals[Reg] = nullptr;
+    auto &Interval = VirtRegIntervals[Reg];
+    delete Interval;
+    Interval = nullptr;
   }
 
   /// Given a register and an instruction, adds a live segment from that