[MemoryBuiltins] Check nobuiltin status when identifying calls to free.

This is usually not a problem because this code's main purpose is
eliminating unused new/delete pairs. We got deletes of nullptr or
nobuiltin deletes of builtin new wrong though.

llvm-svn: 325630

2 files changed, 29 insertions, 11 deletions

diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index 24fedfed772..2aa389e059c 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -112,10 +112,9 @@ static const Function *getCalledFunction(const Value *V, bool LookThroughBitCast
 
   IsNoBuiltin = CS.isNoBuiltin();
 
-  const Function *Callee = CS.getCalledFunction();
-  if (!Callee || !Callee->isDeclaration())
-    return nullptr;
-  return Callee;
+  if (const Function *Callee = CS.getCalledFunction())
+    return Callee;
+  return nullptr;
 }
 
 /// Returns the allocation data for the given value if it's either a call to a
@@ -350,11 +349,10 @@ const CallInst *llvm::extractCallocCall(const Value *I,
 
 /// isFreeCall - Returns non-null if the value is a call to the builtin free()
 const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
-  const CallInst *CI = dyn_cast<CallInst>(I);
-  if (!CI || isa<IntrinsicInst>(CI))
-    return nullptr;
-  Function *Callee = CI->getCalledFunction();
-  if (Callee == nullptr)
+  bool IsNoBuiltinCall;
+  const Function *Callee =
+      getCalledFunction(I, /*LookThroughBitCast=*/false, IsNoBuiltinCall);
+  if (Callee == nullptr || IsNoBuiltinCall)
     return nullptr;
 
   StringRef FnName = Callee->getName();
@@ -400,7 +398,7 @@ const CallInst *llvm::isFreeCall(const Value *I, const TargetLibraryInfo *TLI) {
   if (FTy->getParamType(0) != Type::getInt8PtrTy(Callee->getContext()))
     return nullptr;
 
-  return CI;
+  return dyn_cast<CallInst>(I);
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/llvm/test/Transforms/InstCombine/malloc-free-delete.ll b/llvm/test/Transforms/InstCombine/malloc-free-delete.ll
index d2cf5d02fe3..77737fbc8f3 100644
--- a/llvm/test/Transforms/InstCombine/malloc-free-delete.ll
+++ b/llvm/test/Transforms/InstCombine/malloc-free-delete.ll
@@ -146,7 +146,11 @@ lpad.i:                                           ; preds = %entry
 }
 
 declare i8* @_Znwm(i64) nobuiltin
-declare i8* @_Znwj(i32) nobuiltin
+define i8* @_Znwj(i32 %n) nobuiltin {
+  %z = zext i32 %n to i64
+  call i8* @_Znwm(i64 %z)
+  ret i8* %m
+}
 declare i8* @_Znam(i64) nobuiltin
 declare i8* @_Znaj(i32) nobuiltin
 declare void @_ZdlPv(i8*) nobuiltin
@@ -197,3 +201,19 @@ define void @test9() {
   call void @"\01??3@YAXPEAX@Z"(i8* %new_long_long) builtin
   ret void
 }
+
+define void @test10()  {
+; CHECK-LABEL: @test10
+; CHECK: call void @_ZdlPv
+  call void @_ZdlPv(i8* null)
+  ret void
+}
+
+define void @test11() {
+; CHECK-LABEL: @test11
+; CHECK: call i8* @_Znwm
+; CHECK: call void @_ZdlPv
+  %call = call i8* @_Znwm(i64 8) builtin
+  call void @_ZdlPv(i8* %call)
+  ret void
+}