[llvm] [SLPVectorizer] Use DenseMap::operator[] (NFC) (PR #107123)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata updated https://github.com/llvm/llvm-project/pull/107123

>From e7455938fb9389db298994ec9af09adb8a41bdef Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Tue, 3 Sep 2024 08:26:45 -0700
Subject: [PATCH 1/2] [SLPVectorizer] Use DenseMap::operator[] (NFC)

I'm planning to deprecate and eventually remove
DenseMap::FindAndConstruct in favor of operator[].
---
 .../Transforms/Vectorize/SLPVectorizer.cpp    | 22 +++++++++----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 5c37c2fdd2de3e..8a239c163a84cb 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -11841,9 +11841,9 @@ void BoUpSLP::reorderInputsAccordingToOpcode(ArrayRef<Value *> VL,
 }
 
 Instruction &BoUpSLP::getLastInstructionInBundle(const TreeEntry *E) {
-  auto &Res = EntryToLastInstruction.FindAndConstruct(E);
-  if (Res.second)
-    return *Res.second;
+  auto &Res = EntryToLastInstruction[E];
+  if (Res)
+    return *Res;
   // Get the basic block this bundle is in. All instructions in the bundle
   // should be in this block (except for extractelement-like instructions with
   // constant indeces).
@@ -11947,10 +11947,10 @@ Instruction &BoUpSLP::getLastInstructionInBundle(const TreeEntry *E) {
            return isa<ExtractElementInst, UndefValue>(V) ||
                   areAllOperandsNonInsts(V);
          })))
-      Res.second = FindLastInst();
+      Res = FindLastInst();
     else
-      Res.second = FindFirstInst();
-    return *Res.second;
+      Res = FindFirstInst();
+    return *Res;
   }
 
   // Find the last instruction. The common case should be that BB has been
@@ -11964,7 +11964,7 @@ Instruction &BoUpSLP::getLastInstructionInBundle(const TreeEntry *E) {
     auto *Bundle = BlocksSchedules[BB]->getScheduleData(V);
     if (Bundle && Bundle->isPartOfBundle())
       for (; Bundle; Bundle = Bundle->NextInBundle)
-        Res.second = Bundle->Inst;
+        Res = Bundle->Inst;
   }
 
   // LastInst can still be null at this point if there's either not an entry
@@ -11985,10 +11985,10 @@ Instruction &BoUpSLP::getLastInstructionInBundle(const TreeEntry *E) {
   // not ideal. However, this should be exceedingly rare since it requires that
   // we both exit early from buildTree_rec and that the bundle be out-of-order
   // (causing us to iterate all the way to the end of the block).
-  if (!Res.second)
-    Res.second = FindLastInst();
-  assert(Res.second && "Failed to find last instruction in bundle");
-  return *Res.second;
+  if (!Res)
+    Res = FindLastInst();
+  assert(Res && "Failed to find last instruction in bundle");
+  return *Res;
 }
 
 void BoUpSLP::setInsertPointAfterBundle(const TreeEntry *E) {

>From 92333c3f068c3d2550a72c591524cea79b239e82 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Tue, 3 Sep 2024 10:05:24 -0700
Subject: [PATCH 2/2] Use find and try_emplace instead of operator[].

---
 llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 8a239c163a84cb..7f5c0e7c87cfbb 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -11841,9 +11841,10 @@ void BoUpSLP::reorderInputsAccordingToOpcode(ArrayRef<Value *> VL,
 }
 
 Instruction &BoUpSLP::getLastInstructionInBundle(const TreeEntry *E) {
-  auto &Res = EntryToLastInstruction[E];
-  if (Res)
-    return *Res;
+  auto It = EntryToLastInstruction.find(E);
+  if (It != EntryToLastInstruction.end())
+    return *It->second;
+  auto &Res = EntryToLastInstruction.try_emplace(E).first->second;
   // Get the basic block this bundle is in. All instructions in the bundle
   // should be in this block (except for extractelement-like instructions with
   // constant indeces).