On Thu, 25 Jul 2024, Jason Merrill wrote:
> Tested x86_64-pc-linux-gnu, applying to trunk.
>
> Also built highway to check.
>
> -- 8< --
>
> My patch for 109753 applies the current #pragma target/optimize to a
> function when we compile it, which was a problem for a template
> instantiation deferred until EOF, where different #pragmas are active. So
> let's only do this for artificial functions.
>
> PR c++/115403
> PR c++/109753
>
> gcc/cp/ChangeLog:
>
> * decl.cc (start_preparsed_function): Only call decl_attributes for
> artificial functions.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/ext/pragma-target1.C: New test.
> ---
> gcc/cp/decl.cc | 7 +++++--
> gcc/testsuite/g++.dg/ext/pragma-target1.C | 6 ++++++
> 2 files changed, 11 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/ext/pragma-target1.C
>
> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> index 6b686d75a49..279af21eed0 100644
> --- a/gcc/cp/decl.cc
> +++ b/gcc/cp/decl.cc
> @@ -17882,8 +17882,11 @@ start_preparsed_function (tree decl1, tree attrs,
> int flags)
> doing_friend = true;
> }
>
> - /* Adjust for #pragma target/optimize. */
> - decl_attributes (&decl1, NULL_TREE, 0);
> + /* Adjust for #pragma target/optimize if this is an artificial function
> that
> + (probably) didn't go through grokfndecl. We particularly don't want
> this
> + for deferred instantiations, which should match their template. */
> + if (DECL_ARTIFICIAL (decl1))
> + decl_attributes (&decl1, NULL_TREE, 0);
Couldn't an artificial function get synthesized at EOF if e.g. it's
needed by a deferred instantiation? In that case we'll still call
decl_attributes on it which will inherit the last active #pragma,
which seems unintended. Maybe we should clear #pragma before
processing deferred instantiations?
>
> if (DECL_DECLARED_INLINE_P (decl1)
> && lookup_attribute ("noinline", attrs))
> diff --git a/gcc/testsuite/g++.dg/ext/pragma-target1.C
> b/gcc/testsuite/g++.dg/ext/pragma-target1.C
> new file mode 100644
> index 00000000000..0ce2438da2f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/pragma-target1.C
> @@ -0,0 +1,6 @@
> +// PR c++/115403
> +// { dg-do compile { target x86_64-*-* } }
> +
> +template <typename> __attribute__((always_inline)) inline void AssertEqual()
> {}
> +void TestAllF16FromF32() { AssertEqual<float>(); }
> +#pragma GCC target "sse4.1"
>
> base-commit: 29341f21ce1eb7cdb8cd468e4ceb0d07cf2775e0
> --
> 2.45.2
>
>
