Revert "[Inliner] Propagate callee argument memory access attributes before inlining"

This exposes a miscompile reported in
https://github.com/llvm/llvm-project/issues/95152.

Whether the new inference or MemCpyOpt is at fault depends on
the precise semantics of writeonly attributes. Revert the patch
while this is being pinned down.

This reverts commit 285dbed147e243f416b003e150d67ffb0922ff16.
This reverts commit cda5790e38af5da3ad455eddab36ef16bf3e8104.

1 files changed, 0 insertions, 83 deletions

diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index cfe6349..c4baafd 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -1344,85 +1344,6 @@ static bool MayContainThrowingOrExitingCallAfterCB(CallBase *Begin,
       ++BeginIt, End->getIterator(), InlinerAttributeWindow + 1);
 }
 
-// Add attributes from CB params and Fn attributes that can always be propagated
-// to the corresponding argument / inner callbases.
-static void AddParamAndFnBasicAttributes(const CallBase &CB,
-                                         ValueToValueMapTy &VMap) {
-  auto *CalledFunction = CB.getCalledFunction();
-  auto &Context = CalledFunction->getContext();
-
-  // Collect valid attributes for all params.
-  SmallVector<AttrBuilder> ValidParamAttrs;
-  bool HasAttrToPropagate = false;
-
-  for (unsigned I = 0, E = CB.arg_size(); I < E; ++I) {
-    ValidParamAttrs.emplace_back(AttrBuilder{CB.getContext()});
-    // Access attributes can be propagated to any param with the same underlying
-    // object as the argument.
-    if (CB.paramHasAttr(I, Attribute::ReadNone))
-      ValidParamAttrs.back().addAttribute(Attribute::ReadNone);
-    if (CB.paramHasAttr(I, Attribute::ReadOnly))
-      ValidParamAttrs.back().addAttribute(Attribute::ReadOnly);
-    if (CB.paramHasAttr(I, Attribute::WriteOnly))
-      ValidParamAttrs.back().addAttribute(Attribute::WriteOnly);
-    HasAttrToPropagate |= ValidParamAttrs.back().hasAttributes();
-  }
-
-  // Won't be able to propagate anything.
-  if (!HasAttrToPropagate)
-    return;
-
-  for (BasicBlock &BB : *CalledFunction) {
-    for (Instruction &Ins : BB) {
-      const auto *InnerCB = dyn_cast<CallBase>(&Ins);
-      if (!InnerCB)
-        continue;
-      auto *NewInnerCB = dyn_cast_or_null<CallBase>(VMap.lookup(InnerCB));
-      if (!NewInnerCB)
-        continue;
-      AttributeList AL = NewInnerCB->getAttributes();
-      for (unsigned I = 0, E = InnerCB->arg_size(); I < E; ++I) {
-        // Check if the underlying value for the parameter is an argument.
-        const Value *UnderlyingV =
-            getUnderlyingObject(InnerCB->getArgOperand(I));
-        const Argument *Arg = dyn_cast<Argument>(UnderlyingV);
-        if (!Arg)
-          continue;
-
-        if (AL.hasParamAttr(I, Attribute::ByVal))
-          // It's unsound to propagate memory attributes to byval arguments.
-          // Even if CalledFunction doesn't e.g. write to the argument,
-          // the call to NewInnerCB may write to its by-value copy.
-          continue;
-
-        unsigned ArgNo = Arg->getArgNo();
-        // If so, propagate its access attributes.
-        AL = AL.addParamAttributes(Context, I, ValidParamAttrs[ArgNo]);
-        // We can have conflicting attributes from the inner callsite and
-        // to-be-inlined callsite. In that case, choose the most
-        // restrictive.
-
-        // readonly + writeonly means we can never deref so make readnone.
-        if (AL.hasParamAttr(I, Attribute::ReadOnly) &&
-            AL.hasParamAttr(I, Attribute::WriteOnly))
-          AL = AL.addParamAttribute(Context, I, Attribute::ReadNone);
-
-        // If have readnone, need to clear readonly/writeonly
-        if (AL.hasParamAttr(I, Attribute::ReadNone)) {
-          AL = AL.removeParamAttribute(Context, I, Attribute::ReadOnly);
-          AL = AL.removeParamAttribute(Context, I, Attribute::WriteOnly);
-        }
-
-        // Writable cannot exist in conjunction w/ readonly/readnone
-        if (AL.hasParamAttr(I, Attribute::ReadOnly) ||
-            AL.hasParamAttr(I, Attribute::ReadNone))
-          AL = AL.removeParamAttribute(Context, I, Attribute::Writable);
-      }
-      NewInnerCB->setAttributes(AL);
-    }
-  }
-}
-
 // Only allow these white listed attributes to be propagated back to the
 // callee. This is because other attributes may only be valid on the call
 // itself, i.e. attributes such as signext and zeroext.
@@ -2442,10 +2363,6 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
     // function which feed into its return value.
     AddReturnAttributes(CB, VMap);
 
-    // Clone attributes on the params of the callsite to calls within the
-    // inlined function which use the same param.
-    AddParamAndFnBasicAttributes(CB, VMap);
-
     propagateMemProfMetadata(CalledFunc, CB,
                              InlinedFunctionInfo.ContainsMemProfMetadata, VMap);