sepavloff added a comment.
In D143919#4130178 <https://reviews.llvm.org/D143919#4130178>, @efriedma wrote:
> If the "strictfp" attribute is based on the contents of the function body,
> should we recompute it when the function is instantiated, as opposed to
> copying it? For example, say you have a pragma inside an "if constexpr";
> should that set the strictfp attribute if it's discarded?
>
> Otherwise, I guess updateAttrsForLateParsedTemplate makes sense.
Recomputing is certainly a better solution, as it would provide actual
properties. It however should be applied to all instantiations, not only late
parsed. With this change the code:
template <typename T, bool F>
T templ_01(T x, T y) {
if constexpr (F) {
#pragma STDC FENV_ACCESS ON
return x - y;
} else
return x + y;
}
float func_02(float x, float y) {
return templ_01<float, true>(x, y);
}
float func_03(float x, float y) {
return templ_01<float, false>(x, y);
}
compiled without late parsing produces `func_03` with strictfp attribute.
However constarined intrinsics in it are semantically equivalent to
non-constrained operations. Adding unneeded strictfp attribute is not an error.
================
Comment at: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:824
+ continue;
+ }
+
----------------
efriedma wrote:
> Is this necessary? The non-delayed-parsed case seems to work correctly on
> trunk without any changes, so I suspect the autogenerated
> sema::instantiateTemplateAttribute is doing the right thing.
Yes, it is necessary. Without it the code from the added test crashes, as
constrained intrinsic is used in a function without strictfp attribute.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D143919/new/
https://reviews.llvm.org/D143919
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