https://github.com/MaxEW707 updated
https://github.com/llvm/llvm-project/pull/91689
>From b43a6302009b9a11ef672f3bd01e10342102de44 Mon Sep 17 00:00:00 2001
From: MaxEW707 <max.enrico.wink...@gmail.com>
Date: Thu, 9 May 2024 21:21:22 -0400
Subject: [PATCH 1/2] [clang][Driver] Fix enabling strict alising by default
when the environment is MSVC
---
clang/lib/Driver/ToolChains/Clang.cpp | 5 ++---
clang/test/Driver/Ofast.c | 7 +++++--
clang/test/Driver/clang_f_opts.c | 6 ++++++
3 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp
b/clang/lib/Driver/ToolChains/Clang.cpp
index 0a2ea96de7382..8286c7ae51276 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5651,11 +5651,10 @@ void Clang::ConstructJob(Compilation &C, const
JobAction &JA,
// enabled. This alias option is being used to simplify the hasFlag logic.
OptSpecifier StrictAliasingAliasOption =
OFastEnabled ? options::OPT_Ofast : options::OPT_fstrict_aliasing;
- // We turn strict aliasing off by default if we're in CL mode, since MSVC
+ // We turn strict aliasing off by default if we're Windows MSVC since MSVC
// doesn't do any TBAA.
- bool TBAAOnByDefault = !D.IsCLMode();
if (!Args.hasFlag(options::OPT_fstrict_aliasing, StrictAliasingAliasOption,
- options::OPT_fno_strict_aliasing, TBAAOnByDefault))
+ options::OPT_fno_strict_aliasing, !IsWindowsMSVC))
CmdArgs.push_back("-relaxed-aliasing");
if (!Args.hasFlag(options::OPT_fstruct_path_tbaa,
options::OPT_fno_struct_path_tbaa, true))
diff --git a/clang/test/Driver/Ofast.c b/clang/test/Driver/Ofast.c
index 1f9fc78ec1ef8..8b7f2217eca2f 100644
--- a/clang/test/Driver/Ofast.c
+++ b/clang/test/Driver/Ofast.c
@@ -3,7 +3,9 @@
// RUN: %clang -fno-fast-math -Ofast -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST %s
// RUN: %clang -fno-strict-aliasing -Ofast -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST %s
// RUN: %clang -fno-vectorize -Ofast -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST %s
-// RUN: %clang -Ofast -O2 -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST-O2 %s
+// RUN: %clang -Ofast -O2 -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST-O2 \
+// RUN: %if target={{.*-windows-msvc.*}} %{
--check-prefix=CHECK-OFAST-O2-ALIASING-MSVC %} \
+// RUN: %else %{ --check-prefix=CHECK-OFAST-O2-ALIASING %} %s
// RUN: %clang -Ofast -fno-fast-math -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST-NO-FAST-MATH %s
// RUN: %clang -Ofast -fno-strict-aliasing -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST-NO-STRICT-ALIASING %s
// RUN: %clang -Ofast -fno-vectorize -### %s 2>&1 | FileCheck
-check-prefix=CHECK-OFAST-NO-VECTORIZE %s
@@ -15,7 +17,8 @@
// CHECK-OFAST: -vectorize-loops
// CHECK-OFAST-O2: -cc1
-// CHECK-OFAST-O2-NOT: -relaxed-aliasing
+// CHECK-OFAST-O2-ALIASING-NOT: -relaxed-aliasing
+// CHECK-OFAST-O2-ALIASING-MSVC: -relaxed-aliasing
// CHECK-OFAST-O2-NOT: -ffast-math
// CHECK-OFAST-O2-NOT: -Ofast
// CHECK-OFAST-O2: -vectorize-loops
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index 472d0725a7934..d69cd199ac61d 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -623,3 +623,9 @@
// RUN: %clang -### --target=aarch64-windows-msvc -fno-ms-volatile %s 2>&1 |
FileCheck -check-prefix=CHECK-NO-MS-VOLATILE %s
// CHECK-MS-VOLATILE: -fms-volatile
// CHECK-NO-MS-VOLATILE-NOT: -fms-volatile
+
+// RUN: %clang -### --target=x86_64-pc-windows-msvc %s 2>&1 | FileCheck
-check-prefix=CHECK-NO-STRICT-ALIASING %s
+// RUN: %clang -### --target=x86_64-pc-windows-msvc -fstrict-aliasing %s 2>&1
| FileCheck -check-prefix=CHECK-STRICT-ALIASING %s
+// RUN: %clang -### --target=x86_64-pc-windows-msvc -fno-strict-aliasing %s
2>&1 | FileCheck -check-prefix=CHECK-NO-STRICT-ALIASING %s
+// CHECK-STRICT-ALIASING-NOT: -relaxed-aliasing
+// CHECK-NO-STRICT-ALIASING: -relaxed-aliasing
>From d29a96b7b489c4df4963015d8bb74e3e784bd7b3 Mon Sep 17 00:00:00 2001
From: MaxEW707 <max.enrico.wink...@gmail.com>
Date: Thu, 23 May 2024 19:24:21 -0400
Subject: [PATCH 2/2] Add a release note
---
clang/docs/ReleaseNotes.rst | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index a3c8e4141ca54..7e6e4457f9b0b 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -781,6 +781,10 @@ Windows Support
including STL headers will no longer slow down compile times since
``intrin.h``
is not included from MSVC STL.
+- When the target triple is `*-windows-msvc` strict aliasing is now disabled
by default
+ to ensure compatibility with msvc. Previously strict aliasing was only
disabled if the
+ driver mode was cl.
+
LoongArch Support
^^^^^^^^^^^^^^^^^
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