Motivation:
int foo(int x, int y) { // any compiler will happily inline this function return x / y; } int test(int x, int y) { int r = 0; [[clang::noinline]] r += foo(x, y); // for some reason we don't want any inlining here return r; }
In 2018, @kuhar proposed "Introduce per-callsite inline intrinsics" in https://reviews.llvm.org/D51200 to solve this motivation case (and many others).
This patch solves this problem with call site attribute. The implementation is "smaller" wrt approach which uses new intrinsics and thanks to https://reviews.llvm.org/D79121 (Add nomerge statement attribute to clang), we have got some basic infrastructure to deal with attrs on statements with call expressions.
GCC devs are more inclined to call attribute solution as well, as builtins are problematic for them - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104187. But they have no patch proposal yet so.. We have free hands here.
If this approach makes sense, next future steps would be support for call site attributes for always_inline / flatten.
Can you explain why you made this change? This seems like it'll do the wrong thing for functions because it'll now be duplicating the attribute on each redeclaration. e.g.,
(It seems we already have this bug with nomerge: https://godbolt.org/z/aMTcTdPEP)