Author: Max Winkler Date: 2024-05-24T19:12:38-04:00 New Revision: d63764718c93a40d25cf4ae62b6ea6cb8eda6435
URL: https://github.com/llvm/llvm-project/commit/d63764718c93a40d25cf4ae62b6ea6cb8eda6435 DIFF: https://github.com/llvm/llvm-project/commit/d63764718c93a40d25cf4ae62b6ea6cb8eda6435.diff LOG: [clang][Driver] Fix enabling strict alising by default when the environment is MSVC (#91689) >From looking at the rest of code and from my own understanding, the driver mode is supposed to be independent of MSVC compatibility when the target triple is `*-windows-msvc`. Therefore strict aliasing should be disabled by default when the target triple is `*-windows-msvc` so code assuming MSVC behaves as expected when compiled with Clang. Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/Driver/ToolChains/Clang.cpp clang/test/Driver/Ofast.c clang/test/Driver/clang_f_opts.c Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index fd7f3ee13d9ac..e40b236c914d9 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -878,6 +878,10 @@ 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 ^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 15cf58f9d3339..adb1b2ff566cb 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -5681,11 +5681,10 @@ 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 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
