[clang] 6cf8179 - Don't perform dynamic_cast optimization at -O0.

[Richard Smith via cfe-commits]

Author: Richard Smith
Date: 2023-07-24T22:24:33-07:00
New Revision: 6cf8179661997f8d512cdf944f4f4c0c01cb37c1

URL: https://github.com/llvm/llvm-project/commit/6cf8179661997f8d512cdf944f4f4c0c01cb37c1
DIFF: https://github.com/llvm/llvm-project/commit/6cf8179661997f8d512cdf944f4f4c0c01cb37c1.diff

LOG: Don't perform dynamic_cast optimization at -O0.

It seems preferable to avoid this optimization under -O0, and we're not
set up to emit speculative references to vtables at -O0 in general
anyway.

For #64088.

Added: 
    

Modified: 
    clang/lib/CodeGen/CGExprCXX.cpp
    clang/test/CodeGenCXX/dynamic-cast-exact-disabled.cpp
    clang/test/CodeGenCXX/dynamic-cast-exact.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 6df5e37d9af940..4d3f3e9603d942 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -2276,6 +2276,7 @@ llvm::Value *CodeGenFunction::EmitDynamicCast(Address ThisAddr,
   // If the destination is effectively final, the cast succeeds if and only
   // if the dynamic type of the pointer is exactly the destination type.
   bool IsExact = !IsDynamicCastToVoid &&
+                 CGM.getCodeGenOpts().OptimizationLevel > 0 &&
                  DestRecordTy->getAsCXXRecordDecl()->isEffectivelyFinal() &&
                  CGM.getCXXABI().shouldEmitExactDynamicCast(DestRecordTy);
 

diff  --git a/clang/test/CodeGenCXX/dynamic-cast-exact-disabled.cpp b/clang/test/CodeGenCXX/dynamic-cast-exact-disabled.cpp
index 453337d372b499..9a8ce1997a7f96 100644
--- a/clang/test/CodeGenCXX/dynamic-cast-exact-disabled.cpp
+++ b/clang/test/CodeGenCXX/dynamic-cast-exact-disabled.cpp
@@ -1,7 +1,8 @@
-// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,EXACT
-// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -fvisibility=hidden -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,INEXACT
-// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -fapple-kext -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,INEXACT
-// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -fno-assume-unique-vtables -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,INEXACT
+// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -O1 -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,EXACT
+// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -O0 -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,INEXACT
+// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -O1 -fvisibility=hidden -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,INEXACT
+// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -O1 -fapple-kext -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,INEXACT
+// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -O1 -fno-assume-unique-vtables -emit-llvm -std=c++11 -o - | FileCheck %s --check-prefixes=CHECK,INEXACT
 
 struct A { virtual ~A(); };
 struct B final : A { };

diff  --git a/clang/test/CodeGenCXX/dynamic-cast-exact.cpp b/clang/test/CodeGenCXX/dynamic-cast-exact.cpp
index b1a81db69115eb..676aa975a72686 100644
--- a/clang/test/CodeGenCXX/dynamic-cast-exact.cpp
+++ b/clang/test/CodeGenCXX/dynamic-cast-exact.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -emit-llvm -fcxx-exceptions -fexceptions -std=c++11 -o - | FileCheck %s --implicit-check-not='call {{.*}} @__dynamic_cast'
+// RUN: %clang_cc1 -I%S %s -triple x86_64-apple-darwin10 -emit-llvm -fcxx-exceptions -fexceptions -std=c++11 -o - -O1 -disable-llvm-passes | FileCheck %s --implicit-check-not='call {{.*}} @__dynamic_cast'
 struct Offset { virtual ~Offset(); };
 struct A { virtual ~A(); };
 struct B final : Offset, A { };