From c4ad24deeed8165f1c636473459982b8d9570e74 Mon Sep 17 00:00:00 2001
From: Johannes Doerfert <johannes@jdoerfert.de>
Date: Thu, 26 Jan 2023 21:05:30 -0800
Subject: [PATCH] [Attributor][NCFI] Explicitly state what interfering accesses
 to look for

We used to check the query instructions for effects but that does not
work well with complex accesses we will probably support in the future.
Now we simply let the user decide what accesses to look for.
---
 llvm/include/llvm/Transforms/IPO/Attributor.h    | 1 +
 llvm/lib/Transforms/IPO/Attributor.cpp           | 6 ++++--
 llvm/lib/Transforms/IPO/AttributorAttributes.cpp | 3 +--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/Transforms/IPO/Attributor.h b/llvm/include/llvm/Transforms/IPO/Attributor.h
index da171f8..9cd351f 100644
--- a/llvm/include/llvm/Transforms/IPO/Attributor.h
+++ b/llvm/include/llvm/Transforms/IPO/Attributor.h
@@ -5483,6 +5483,7 @@ struct AAPointerInfo : public AbstractAttribute {
   /// read the intial value of the underlying memory.
   virtual bool forallInterferingAccesses(
       Attributor &A, const AbstractAttribute &QueryingAA, Instruction &I,
+      bool FindInterferingWrites, bool FindInterferingReads,
       function_ref<bool(const Access &, bool)> CB, bool &HasBeenWrittenTo,
       AA::RangeTy &Range) const = 0;
 
diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index b9134ce..67d21ad 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -451,8 +451,10 @@ static bool getPotentialCopiesOfMemoryValue(
     AA::RangeTy Range;
     auto &PI = A.getAAFor<AAPointerInfo>(QueryingAA, IRPosition::value(Obj),
                                          DepClassTy::NONE);
-    if (!PI.forallInterferingAccesses(A, QueryingAA, I, CheckAccess,
-                                      HasBeenWrittenTo, Range)) {
+    if (!PI.forallInterferingAccesses(A, QueryingAA, I,
+                                      /* FindInterferingWrites */ IsLoad,
+                                      /* FindInterferingReads */ !IsLoad,
+                                      CheckAccess, HasBeenWrittenTo, Range)) {
       LLVM_DEBUG(
           dbgs()
           << "Failed to verify all interfering accesses for underlying object: "
diff --git a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
index 2730adf..569a4a9 100644
--- a/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
+++ b/llvm/lib/Transforms/IPO/AttributorAttributes.cpp
@@ -1032,6 +1032,7 @@ struct AAPointerInfoImpl
 
   bool forallInterferingAccesses(
       Attributor &A, const AbstractAttribute &QueryingAA, Instruction &I,
+      bool FindInterferingWrites, bool FindInterferingReads,
       function_ref<bool(const Access &, bool)> UserCB, bool &HasBeenWrittenTo,
       AA::RangeTy &Range) const override {
     HasBeenWrittenTo = false;
@@ -1099,8 +1100,6 @@ struct AAPointerInfoImpl
     const auto &NoRecurseAA = A.getAAFor<AANoRecurse>(
         QueryingAA, IRPosition::function(Scope), DepClassTy::OPTIONAL);
 
-    const bool FindInterferingWrites = I.mayReadFromMemory();
-    const bool FindInterferingReads = I.mayWriteToMemory();
     const bool UseDominanceReasoning =
         FindInterferingWrites && NoRecurseAA.isKnownNoRecurse();
     const DominatorTree *DT =
-- 
2.7.4