From 259390de9af659e2432c5b2af041ec6576c1b26d Mon Sep 17 00:00:00 2001
From: Arthur Eubanks <aeubanks@google.com>
Date: Wed, 6 Oct 2021 14:32:08 -0700
Subject: [PATCH] [LCG] Don't skip invalidation of LazyCallGraph if CFG
 analyses are preserved

The CFG being changed and the overall call graph are not related, we can introduce/remove calls without changing the CFG.

Resolves one of the issues in PR51946.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D111275
---
 llvm/lib/Analysis/LazyCallGraph.cpp            |  3 +--
 llvm/test/Analysis/LazyCallGraph/invalidate.ll | 10 ++++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/Analysis/LazyCallGraph/invalidate.ll

diff --git a/llvm/lib/Analysis/LazyCallGraph.cpp b/llvm/lib/Analysis/LazyCallGraph.cpp
index 8f87552fca1f..8170c32a2d15 100644
--- a/llvm/lib/Analysis/LazyCallGraph.cpp
+++ b/llvm/lib/Analysis/LazyCallGraph.cpp
@@ -220,8 +220,7 @@ bool LazyCallGraph::invalidate(Module &, const PreservedAnalyses &PA,
   // Check whether the analysis, all analyses on functions, or the function's
   // CFG have been preserved.
   auto PAC = PA.getChecker<llvm::LazyCallGraphAnalysis>();
-  return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Module>>() ||
-           PAC.preservedSet<CFGAnalyses>());
+  return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Module>>());
 }
 
 LazyCallGraph &LazyCallGraph::operator=(LazyCallGraph &&G) {
diff --git a/llvm/test/Analysis/LazyCallGraph/invalidate.ll b/llvm/test/Analysis/LazyCallGraph/invalidate.ll
new file mode 100644
index 000000000000..b2f421086d3c
--- /dev/null
+++ b/llvm/test/Analysis/LazyCallGraph/invalidate.ll
@@ -0,0 +1,10 @@
+; Make sure we invalidate lcg even when preserving domtree
+; RUN: opt -passes='require<lcg>,function(instcombine)' -debug-pass-manager -disable-output < %s 2>&1 | FileCheck %s
+
+; CHECK: Invalidating {{.*}} LazyCallGraphAnalysis
+
+define void @f() {
+lbl:
+  %a = add i32 1, 2
+  unreachable
+}