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Diffstat (limited to 'gcc/doc/extend.texi')
| -rw-r--r-- | gcc/doc/extend.texi | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index a72fb7f..a281f92 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -2207,6 +2207,20 @@ SSE registers instead of on the stack. Functions that take a variable number of arguments will continue to pass all of their floating point arguments on the stack. +@item force_align_arg_pointer +@cindex @code{force_align_arg_pointer} attribute +On the Intel x86, the @code{force_align_arg_pointer} attribute may be +applied to individual function definitions, generating an alternate +prologue and epilogue that realigns the runtime stack. This supports +mixing legacy codes that run with a 4-byte aligned stack with modern +codes that keep a 16-byte stack for SSE compatibility. The alternate +prologue and epilogue are slower and bigger than the regular ones, and +the alternate prologue requires a scratch register; this lowers the +number of registers available if used in conjunction with the +@code{regparm} attribute. The @code{force_align_arg_pointer} +attribute is incompatible with nested functions; this is considered a +hard error. + @item returns_twice @cindex @code{returns_twice} attribute The @code{returns_twice} attribute tells the compiler that a function may |