[llvm] [PtrUseVisitor] Allow using Argument as a starting point (PR #106308)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-analysis

Author: Artem Belevich (Artem-B)

<details>
<summary>Changes</summary>

Argument is another possible starting point for the pointer traversal, and PtrUseVisitor should be able to handle it.

---
Full diff: https://github.com/llvm/llvm-project/pull/106308.diff


2 Files Affected:

- (modified) llvm/include/llvm/Analysis/PtrUseVisitor.h (+5-2) 
- (modified) llvm/lib/Analysis/PtrUseVisitor.cpp (+1-1) 


``````````diff
diff --git a/llvm/include/llvm/Analysis/PtrUseVisitor.h b/llvm/include/llvm/Analysis/PtrUseVisitor.h
index 86206b2d5e9f88..aa38c29e41f41b 100644
--- a/llvm/include/llvm/Analysis/PtrUseVisitor.h
+++ b/llvm/include/llvm/Analysis/PtrUseVisitor.h
@@ -158,7 +158,7 @@ class PtrUseVisitorBase {
   ///
   /// This will visit the users with the same offset of the current visit
   /// (including an unknown offset if that is the current state).
-  void enqueueUsers(Instruction &I);
+  void enqueueUsers(Value &I);
 
   /// Walk the operands of a GEP and adjust the offset as appropriate.
   ///
@@ -209,11 +209,14 @@ class PtrUseVisitor : protected InstVisitor<DerivedT>,
 
   /// Recursively visit the uses of the given pointer.
   /// \returns An info struct about the pointer. See \c PtrInfo for details.
-  PtrInfo visitPtr(Instruction &I) {
+  /// We may also need to process Argument pointers, so the input uses is 
+  /// a common Value type.
+  PtrInfo visitPtr(Value &I) {
     // This must be a pointer type. Get an integer type suitable to hold
     // offsets on this pointer.
     // FIXME: Support a vector of pointers.
     assert(I.getType()->isPointerTy());
+    assert(isa<Instruction>(I) || isa<Argument>(I));
     IntegerType *IntIdxTy = cast<IntegerType>(DL.getIndexType(I.getType()));
     IsOffsetKnown = true;
     Offset = APInt(IntIdxTy->getBitWidth(), 0);
diff --git a/llvm/lib/Analysis/PtrUseVisitor.cpp b/llvm/lib/Analysis/PtrUseVisitor.cpp
index 49304818d7efed..9c79546f491eff 100644
--- a/llvm/lib/Analysis/PtrUseVisitor.cpp
+++ b/llvm/lib/Analysis/PtrUseVisitor.cpp
@@ -17,7 +17,7 @@
 
 using namespace llvm;
 
-void detail::PtrUseVisitorBase::enqueueUsers(Instruction &I) {
+void detail::PtrUseVisitorBase::enqueueUsers(Value &I) {
   for (Use &U : I.uses()) {
     if (VisitedUses.insert(&U).second) {
       UseToVisit NewU = {

``````````

</details>


https://github.com/llvm/llvm-project/pull/106308