[llvm] [Analysis][NFC] Clean-up in ScalarEvolution when copying predicates (PR #108851)

[David Sherwood via llvm-commits]

https://github.com/david-arm updated https://github.com/llvm/llvm-project/pull/108851

>From 2748bde87ce8638ba8d1d20e2e5d54036104c1aa Mon Sep 17 00:00:00 2001
From: David Sherwood <david.sherwood at arm.com>
Date: Mon, 16 Sep 2024 16:09:33 +0000
Subject: [PATCH] [Analysis][NFC] Clean-up in ScalarEvolution when copying
 predicates

There are a few places in ScalarEvolution.cpp where we copy
predicates from one list to another and they have a similar
pattern:

  for (const auto *P : ENT.Predicates)
    Predicates->push_back(P);

We can avoid the loop by writing them like this:

  append_range(*Predicates, ENT.Predicates)

which may end up being more efficient since we only have to
try reserving more space once.
---
 llvm/lib/Analysis/ScalarEvolution.cpp | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 57e03f667ba6ff..e06863b6deb902 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -8594,8 +8594,7 @@ const SCEV *ScalarEvolution::BackedgeTakenInfo::getExact(
     Ops.push_back(BECount);
 
     if (Preds)
-      for (const auto *P : ENT.Predicates)
-        Preds->push_back(P);
+      append_range(*Preds, ENT.Predicates);
 
     assert((Preds || ENT.hasAlwaysTruePredicate()) &&
            "Predicate should be always true!");
@@ -8616,8 +8615,7 @@ ScalarEvolution::BackedgeTakenInfo::getExitNotTaken(
       if (ENT.hasAlwaysTruePredicate())
         return &ENT;
       else if (Predicates) {
-        for (const auto *P : ENT.Predicates)
-          Predicates->push_back(P);
+        append_range(*Predicates, ENT.Predicates);
         return &ENT;
       }
     }
@@ -8659,8 +8657,7 @@ const SCEV *ScalarEvolution::BackedgeTakenInfo::getSymbolicMax(
                "dominate latch!");
         ExitCounts.push_back(ExitCount);
         if (Predicates)
-          for (const auto *P : ENT.Predicates)
-            Predicates->push_back(P);
+          append_range(*Predicates, ENT.Predicates);
 
         assert((Predicates || ENT.hasAlwaysTruePredicate()) &&
                "Predicate should be always true!");
@@ -14804,8 +14801,7 @@ const SCEVAddRecExpr *ScalarEvolution::convertSCEVToAddRecWithPredicates(
 
   // Since the transformation was successful, we can now transfer the SCEV
   // predicates.
-  for (const auto *P : TransformPreds)
-    Preds.insert(P);
+  Preds.insert(TransformPreds.begin(), TransformPreds.end());
 
   return AddRec;
 }