| Message ID | 20240124193134.622934-6-ak@linux.intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/5] Improve must tail in RTL backend | expand |
On 24 January 2024 20:30:45 CET, Andi Kleen <ak@linux.intel.com> wrote: >--- > gcc/doc/extend.texi | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > >diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi >index 0bc586d120e7..c68d32bed8de 100644 >--- a/gcc/doc/extend.texi >+++ b/gcc/doc/extend.texi >@@ -9867,6 +9867,22 @@ foo (int x, int y) > @code{y} is not actually incremented and the compiler can but does not > have to optimize it to just @code{return 42 + 42;}. > >+@cindex @code{musttail} statement attribute >+@item musttail >+ >+The @code{gnu::musttail} or @code{clang::hottail} attribute AFAICS this patchset does not handle hottail ? thanks, >+can be applied to a return statement that returns the value >+of a call to indicate that the call must be a tail call >+that does not allocate extra stack space. >+ >+@smallexample >+[[gnu::musttail]] return foo(); >+@end smallexample >+ >+If the compiler cannot generate a tail call it will generate >+an error. Tail calls generally require enabling optimization. >+On some targets they may not be supported. >+ > @end table > > @node Attribute Syntax
On Thu, Jan 25, 2024 at 07:51:21AM +0100, rep.dot.nop@gmail.com wrote: > On 24 January 2024 20:30:45 CET, Andi Kleen <ak@linux.intel.com> wrote: > >--- > > gcc/doc/extend.texi | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > >diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi > >index 0bc586d120e7..c68d32bed8de 100644 > >--- a/gcc/doc/extend.texi > >+++ b/gcc/doc/extend.texi > >@@ -9867,6 +9867,22 @@ foo (int x, int y) > > @code{y} is not actually incremented and the compiler can but does not > > have to optimize it to just @code{return 42 + 42;}. > > > >+@cindex @code{musttail} statement attribute > >+@item musttail > >+ > >+The @code{gnu::musttail} or @code{clang::hottail} attribute > > AFAICS this patchset does not handle hottail ? Thanks. Fixed the typo. -Andi
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 0bc586d120e7..c68d32bed8de 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -9867,6 +9867,22 @@ foo (int x, int y) @code{y} is not actually incremented and the compiler can but does not have to optimize it to just @code{return 42 + 42;}. +@cindex @code{musttail} statement attribute +@item musttail + +The @code{gnu::musttail} or @code{clang::hottail} attribute +can be applied to a return statement that returns the value +of a call to indicate that the call must be a tail call +that does not allocate extra stack space. + +@smallexample +[[gnu::musttail]] return foo(); +@end smallexample + +If the compiler cannot generate a tail call it will generate +an error. Tail calls generally require enabling optimization. +On some targets they may not be supported. + @end table @node Attribute Syntax