[PATCH] D38735: [ScheduleDAGInstrs] fix behavior of getUnderlyingObjectsForCodeGen when no identifiable object found

[Hiroshi Inoue via Phabricator via llvm-commits]

inouehrs created this revision.

This patch fixes the bug introduced in my previous patch https://reviews.llvm.org/D35907 reported by http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20171002/491452.html .

Before https://reviews.llvm.org/D35907, when `GetUnderlyingObjects` fails to find an identifiable object, `allMMOsOkay` lambda in `getUnderlyingObjectsForInstr` returns false and `Objects` vector is cleared. This behavior is unintentionally changed by https://reviews.llvm.org/D35907.

This patch makes the behavior for such case same as the previous behavior.
Since https://reviews.llvm.org/D35907 introduced a wrapper function `getUnderlyingObjectsForCodeGen` around `GetUnderlyingObjects`, `getUnderlyingObjectsForCodeGen` is modified to return a boolean value to ask the caller to clear the `Objects` vector.


https://reviews.llvm.org/D38735

Files:
  include/llvm/Analysis/ValueTracking.h
  lib/Analysis/ValueTracking.cpp
  lib/CodeGen/ScheduleDAGInstrs.cpp


Index: lib/CodeGen/ScheduleDAGInstrs.cpp
===================================================================
--- lib/CodeGen/ScheduleDAGInstrs.cpp
+++ lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -151,7 +151,8 @@
         Objects.push_back(UnderlyingObjectsVector::value_type(PSV, MayAlias));
       } else if (const Value *V = MMO->getValue()) {
         SmallVector<Value *, 4> Objs;
-        getUnderlyingObjectsForCodeGen(V, Objs, DL);
+        if (!getUnderlyingObjectsForCodeGen(V, Objs, DL))
+          return false;
 
         for (Value *V : Objs) {
           assert(isIdentifiedObject(V));
Index: lib/Analysis/ValueTracking.cpp
===================================================================
--- lib/Analysis/ValueTracking.cpp
+++ lib/Analysis/ValueTracking.cpp
@@ -3428,7 +3428,8 @@
 
 /// This is a wrapper around GetUnderlyingObjects and adds support for basic
 /// ptrtoint+arithmetic+inttoptr sequences.
-void llvm::getUnderlyingObjectsForCodeGen(const Value *V,
+/// It returns false if unidentified object is found in GetUnderlyingObjects.
+bool llvm::getUnderlyingObjectsForCodeGen(const Value *V,
                           SmallVectorImpl<Value *> &Objects,
                           const DataLayout &DL) {
   SmallPtrSet<const Value *, 16> Visited;
@@ -3454,11 +3455,12 @@
       // getUnderlyingObjectsForCodeGen also fails for safety.
       if (!isIdentifiedObject(V)) {
         Objects.clear();
-        return;
+        return false;
       }
       Objects.push_back(const_cast<Value *>(V));
     }
   } while (!Working.empty());
+  return true;
 }
 
 /// Return true if the only users of this pointer are lifetime markers.
Index: include/llvm/Analysis/ValueTracking.h
===================================================================
--- include/llvm/Analysis/ValueTracking.h
+++ include/llvm/Analysis/ValueTracking.h
@@ -323,7 +323,7 @@
 
   /// This is a wrapper around GetUnderlyingObjects and adds support for basic
   /// ptrtoint+arithmetic+inttoptr sequences.
-  void getUnderlyingObjectsForCodeGen(const Value *V,
+  bool getUnderlyingObjectsForCodeGen(const Value *V,
                             SmallVectorImpl<Value *> &Objects,
                             const DataLayout &DL);
 


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