[llvm] [ThinLTO][WPD] LICM a loop invariant check (PR #164862)

[Teresa Johnson via llvm-commits]

https://github.com/teresajohnson created https://github.com/llvm/llvm-project/pull/164862

Move a loop invariant check out of the innermost loop. I measured a
small but consistent thin link speedup from this change for a large
target (0.75%).


>From 59827a6166d3a0552f3b65052aee3b81e6241808 Mon Sep 17 00:00:00 2001
From: Teresa Johnson <tejohnson at google.com>
Date: Thu, 23 Oct 2025 10:58:33 -0700
Subject: [PATCH] [ThinLTO][WPD] LICM a loop invariant check

Move a loop invariant check out of the innermost loop. I measured a
small but consistent thin link speedup from this change for a large
target (0.75%).
---
 llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
index 6909a282b3129..5174e2361b66f 100644
--- a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
+++ b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
@@ -948,17 +948,17 @@ void llvm::updateVCallVisibilityInIndex(
     // linker, as we have no information on their eventual use.
     if (DynamicExportSymbols.count(P.first))
       continue;
+    // With validation enabled, we want to exclude symbols visible to regular
+    // objects. Local symbols will be in this group due to the current
+    // implementation but those with VCallVisibilityTranslationUnit will have
+    // already been marked in clang so are unaffected.
+    if (VisibleToRegularObjSymbols.count(P.first))
+      continue;
     for (auto &S : P.second.getSummaryList()) {
       auto *GVar = dyn_cast<GlobalVarSummary>(S.get());
       if (!GVar ||
           GVar->getVCallVisibility() != GlobalObject::VCallVisibilityPublic)
         continue;
-      // With validation enabled, we want to exclude symbols visible to regular
-      // objects. Local symbols will be in this group due to the current
-      // implementation but those with VCallVisibilityTranslationUnit will have
-      // already been marked in clang so are unaffected.
-      if (VisibleToRegularObjSymbols.count(P.first))
-        continue;
       GVar->setVCallVisibility(GlobalObject::VCallVisibilityLinkageUnit);
     }
   }