4 files changed, 40 insertions, 28 deletions

diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index 0f4bfb8e2fb..eaac506dec4 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -388,6 +388,36 @@ bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
   return true;
 }
 
+ConstantInt *llvm::lowerObjectSizeCall(IntrinsicInst *ObjectSize,
+                                       const DataLayout &DL,
+                                       const TargetLibraryInfo *TLI,
+                                       bool MustSucceed) {
+  assert(ObjectSize->getIntrinsicID() == Intrinsic::objectsize &&
+         "ObjectSize must be a call to llvm.objectsize!");
+
+  bool MaxVal = cast<ConstantInt>(ObjectSize->getArgOperand(1))->isZero();
+  ObjSizeMode Mode;
+  // Unless we have to fold this to something, try to be as accurate as
+  // possible.
+  if (MustSucceed)
+    Mode = MaxVal ? ObjSizeMode::Max : ObjSizeMode::Min;
+  else
+    Mode = ObjSizeMode::Exact;
+
+  // FIXME: Does it make sense to just return a failure value if the size won't
+  // fit in the output and `!MustSucceed`?
+  uint64_t Size;
+  auto *ResultType = cast<IntegerType>(ObjectSize->getType());
+  if (getObjectSize(ObjectSize->getArgOperand(0), Size, DL, TLI, false, Mode) &&
+      isUIntN(ResultType->getBitWidth(), Size))
+    return ConstantInt::get(ResultType, Size);
+
+  if (!MustSucceed)
+    return nullptr;
+
+  return ConstantInt::get(ResultType, MaxVal ? -1ULL : 0);
+}
+
 STATISTIC(ObjectVisitorArgument,
           "Number of arguments with unsolved size and offset");
 STATISTIC(ObjectVisitorLoad,
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 1e5d682a331..3dea9eb6b1f 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -1948,18 +1948,8 @@ bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool& ModifiedDT) {
     default: break;
     case Intrinsic::objectsize: {
       // Lower all uses of llvm.objectsize.*
-      uint64_t Size;
-      Type *ReturnTy = CI->getType();
-      Constant *RetVal = nullptr;
-      ConstantInt *Op1 = cast<ConstantInt>(II->getArgOperand(1));
-      ObjSizeMode Mode = Op1->isZero() ? ObjSizeMode::Max : ObjSizeMode::Min;
-      if (getObjectSize(II->getArgOperand(0),
-                        Size, *DL, TLInfo, false, Mode)) {
-        RetVal = ConstantInt::get(ReturnTy, Size);
-      } else {
-        RetVal = ConstantInt::get(ReturnTy,
-                                  Mode == ObjSizeMode::Min ? 0 : -1ULL);
-      }
+      ConstantInt *RetVal =
+          lowerObjectSizeCall(II, *DL, TLInfo, /*MustSucceed=*/true);
       // Substituting this can cause recursive simplifications, which can
       // invalidate our iterator.  Use a WeakVH to hold onto it in case this
       // happens.
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 4d432d56aa3..eb5c63433e7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1440,17 +1440,12 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
 
   switch (II->getIntrinsicID()) {
   default: break;
-  case Intrinsic::objectsize: {
-    uint64_t Size;
-    if (getObjectSize(II->getArgOperand(0), Size, DL, &TLI)) {
-      APInt APSize(II->getType()->getIntegerBitWidth(), Size);
-      // Equality check to be sure that `Size` can fit in a value of type
-      // `II->getType()`
-      if (APSize == Size)
-        return replaceInstUsesWith(CI, ConstantInt::get(II->getType(), APSize));
-    }
+  case Intrinsic::objectsize:
+    if (ConstantInt *N =
+            lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/false))
+      return replaceInstUsesWith(CI, N);
     return nullptr;
-  }
+
   case Intrinsic::bswap: {
     Value *IIOperand = II->getArgOperand(0);
     Value *X = nullptr;
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 0d29c1dceea..9a52874c4c2 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2027,12 +2027,9 @@ Instruction *InstCombiner::visitAllocSite(Instruction &MI) {
 
       if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
         if (II->getIntrinsicID() == Intrinsic::objectsize) {
-          uint64_t Size;
-          if (!getObjectSize(II->getArgOperand(0), Size, DL, &TLI)) {
-            ConstantInt *CI = cast<ConstantInt>(II->getArgOperand(1));
-            Size = CI->isZero() ? -1ULL : 0;
-          }
-          replaceInstUsesWith(*I, ConstantInt::get(I->getType(), Size));
+          ConstantInt *Result = lowerObjectSizeCall(II, DL, &TLI,
+                                                    /*MustSucceed=*/true);
+          replaceInstUsesWith(*I, Result);
           eraseInstFromFunction(*I);
           Users[i] = nullptr; // Skip examining in the next loop.
         }