Address review comments.

Author: jcranmer-intel

clang/docs/ReleaseNotes.rst

@@ -145,9 +145,10 @@ Non-comprehensive list of changes in this release
 - ``__builtin_addc``, ``__builtin_subc``, and the other sizes of those
   builtins are now constexpr and may be used in constant expressions.
 
-* Code compiled with ``-shared`` and ``-ffast-math`` will no longer enable
-  flush-to-zero floating-point mode by default. This decision can be overridden
-  with use of ``-mdaz-ftz``. This behavior now matches GCC's behavior.
+* Shared libraries linked with either the ``-ffast-math``, ``-Ofast``, or
+  ``-funsafe-math-optimizations`` flags will no longer enable flush-to-zero
+  floating-point mode by default. This decision can be overridden with use of
+  ``-mdaz-ftz``. This behavior now matches GCC's behavior.
   (`#57589 <https://github.com/llvm/llvm-project/issues/57589>`_)
 
 New Compiler Flags

clang/include/clang/Driver/Options.td

@@ -2584,7 +2584,7 @@ defm protect_parens : BoolFOption<"protect-parens",
 defm daz_ftz : SimpleMFlag<"daz-ftz",
   "Globally set", "Do not globally set",
   " the denormals-are-zero (DAZ) and flush-to-zero (FTZ) bits in the "
-  "floating-point control register on program startup.">;
+  "floating-point control register on program startup">;
 
 def ffor_scope : Flag<["-"], "ffor-scope">, Group<f_Group>;
 def fno_for_scope : Flag<["-"], "fno-for-scope">, Group<f_Group>;

clang/test/Driver/linux-ld.c

@@ -1571,36 +1571,28 @@
 // RUN:   | FileCheck --check-prefix=CHECK-NOCRTFASTMATH %s
 // Don't link crtfastmath.o with -shared
 // RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -ffast-math -shared \
-// RUN:        --gcc-toolchain="" \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NOCRTFASTMATH %s
 // RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -Ofast -shared \
-// RUN:        --gcc-toolchain="" \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NOCRTFASTMATH %s
 // Check for effects of -mdaz-ftz
-// RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -ffast-math -shared -mdaz-ftz \
-// RUN:        --gcc-toolchain="" \
+// RUN: %clang --target=x86_64-unknown-linux -### %s -ffast-math -shared -mdaz-ftz \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-CRTFASTMATH %s
 // RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -ffast-math -mdaz-ftz \
-// RUN:        --gcc-toolchain="" \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-CRTFASTMATH %s
 // RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -mdaz-ftz \
-// RUN:        --gcc-toolchain="" \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-CRTFASTMATH %s
-// RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -ffast-math -shared -mno-daz-ftz \
-// RUN:        --gcc-toolchain="" \
+// RUN: %clang --target=x86_64-unknown-linux -### %s -ffast-math -shared -mno-daz-ftz \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NOCRTFASTMATH %s
 // RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -ffast-math -mno-daz-ftz \
-// RUN:        --gcc-toolchain="" \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NOCRTFASTMATH %s
 // RUN: %clang --target=x86_64-unknown-linux -no-pie -### %s -mno-daz-ftz \
-// RUN:        --gcc-toolchain="" \
 // RUN:        --sysroot=%S/Inputs/basic_linux_tree 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-NOCRTFASTMATH %s
 // CHECK-CRTFASTMATH: usr/lib/gcc/x86_64-unknown-linux/10.2.0{{/|\\\\}}crtfastmath.o