Revert "[Inliner] Propagate more attributes to params when inlining (#91101)"

This reverts commit ae778ae7ce72219270c30d5c8b3d88c9a4803f81.

Creates broken IR, see comments in #91101.

1 files changed, 16 insertions, 74 deletions

diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp
index 71ca527..55ad2b6d 100644
--- a/llvm/lib/Transforms/Utils/InlineFunction.cpp
+++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp
@@ -34,7 +34,6 @@
 #include "llvm/Analysis/VectorUtils.h"
 #include "llvm/IR/Argument.h"
 #include "llvm/IR/AttributeMask.h"
-#include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Constant.h"
@@ -60,7 +59,6 @@
 #include "llvm/IR/MDBuilder.h"
 #include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
-#include "llvm/IR/PatternMatch.h"
 #include "llvm/IR/ProfDataUtils.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/User.h"
@@ -1360,36 +1358,18 @@ static void AddParamAndFnBasicAttributes(const CallBase &CB,
   auto &Context = CalledFunction->getContext();
 
   // Collect valid attributes for all params.
-  SmallVector<AttrBuilder> ValidObjParamAttrs, ValidExactParamAttrs;
+  SmallVector<AttrBuilder> ValidParamAttrs;
   bool HasAttrToPropagate = false;
 
-  // Attributes we can only propagate if the exact parameter is forwarded.
-  // We can propagate both poison generating and UB generating attributes
-  // without any extra checks. The only attribute that is tricky to propagate
-  // is `noundef` (skipped for now) as that can create new UB where previous
-  // behavior was just using a poison value.
-  static const Attribute::AttrKind ExactAttrsToPropagate[] = {
-      Attribute::Dereferenceable, Attribute::DereferenceableOrNull,
-      Attribute::NonNull, Attribute::Alignment, Attribute::Range};
-
   for (unsigned I = 0, E = CB.arg_size(); I < E; ++I) {
-    ValidObjParamAttrs.emplace_back(AttrBuilder{CB.getContext()});
-    ValidExactParamAttrs.emplace_back(AttrBuilder{CB.getContext()});
+    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))
-      ValidObjParamAttrs.back().addAttribute(Attribute::ReadNone);
+      ValidParamAttrs.back().addAttribute(Attribute::ReadNone);
     if (CB.paramHasAttr(I, Attribute::ReadOnly))
-      ValidObjParamAttrs.back().addAttribute(Attribute::ReadOnly);
-
-    for (Attribute::AttrKind AK : ExactAttrsToPropagate) {
-      Attribute Attr = CB.getParamAttr(I, AK);
-      if (Attr.isValid())
-        ValidExactParamAttrs.back().addAttribute(Attr);
-    }
-
-    HasAttrToPropagate |= ValidObjParamAttrs.back().hasAttributes();
-    HasAttrToPropagate |= ValidExactParamAttrs.back().hasAttributes();
+      ValidParamAttrs.back().addAttribute(Attribute::ReadOnly);
+    HasAttrToPropagate |= ValidParamAttrs.back().hasAttributes();
   }
 
   // Won't be able to propagate anything.
@@ -1411,60 +1391,22 @@ static void AddParamAndFnBasicAttributes(const CallBase &CB,
 
       AttributeList AL = NewInnerCB->getAttributes();
       for (unsigned I = 0, E = InnerCB->arg_size(); I < E; ++I) {
-        // It's unsound or requires special handling to propagate
-        // attributes to byval arguments. Even if CalledFunction
-        // doesn't e.g. write to the argument (readonly), the call to
-        // NewInnerCB may write to its by-value copy.
-        if (NewInnerCB->paramHasAttr(I, Attribute::ByVal))
+        // 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;
 
-        // Don't bother propagating attrs to constants.
-        if (match(NewInnerCB->getArgOperand(I),
-                  llvm::PatternMatch::m_ImmConstant()))
+        if (NewInnerCB->paramHasAttr(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;
 
-        // Check if the underlying value for the parameter is an argument.
-        const Argument *Arg = dyn_cast<Argument>(InnerCB->getArgOperand(I));
-        unsigned ArgNo;
-        if (Arg) {
-          ArgNo = Arg->getArgNo();
-          // For dereferenceable, dereferenceable_or_null, align, etc...
-          // we don't want to propagate if the existing param has the same
-          // attribute with "better" constraints. So  remove from the
-          // new AL if the region of the existing param is larger than
-          // what we can propagate.
-          AttrBuilder NewAB{
-              Context, AttributeSet::get(Context, ValidExactParamAttrs[ArgNo])};
-          if (AL.getParamDereferenceableBytes(I) >
-              NewAB.getDereferenceableBytes())
-            NewAB.removeAttribute(Attribute::Dereferenceable);
-          if (AL.getParamDereferenceableOrNullBytes(I) >
-              NewAB.getDereferenceableOrNullBytes())
-            NewAB.removeAttribute(Attribute::DereferenceableOrNull);
-          if (AL.getParamAlignment(I).valueOrOne() >
-              NewAB.getAlignment().valueOrOne())
-            NewAB.removeAttribute(Attribute::Alignment);
-          if (auto ExistingRange = AL.getParamRange(I)) {
-            if (auto NewRange = NewAB.getRange()) {
-              ConstantRange CombinedRange =
-                  ExistingRange->intersectWith(*NewRange);
-              NewAB.removeAttribute(Attribute::Range);
-              NewAB.addRangeAttr(CombinedRange);
-            }
-          }
-          AL = AL.addParamAttributes(Context, I, NewAB);
-        } else {
-          // Check if the underlying value for the parameter is an argument.
-          const Value *UnderlyingV =
-              getUnderlyingObject(InnerCB->getArgOperand(I));
-          Arg = dyn_cast<Argument>(UnderlyingV);
-          if (!Arg)
-            continue;
-          ArgNo = Arg->getArgNo();
-        }
-
+        unsigned ArgNo = Arg->getArgNo();
         // If so, propagate its access attributes.
-        AL = AL.addParamAttributes(Context, I, ValidObjParamAttrs[ArgNo]);
+        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.