attr-alwaysinline.c: New.

2002-02-21  Aldy Hernandez  <aldyh@redhat.com>

        * gcc.dg/attr-alwaysinline.c: New.

        * c-common.c (c_common_post_options): Set inline trees by
        default.

        * doc/extend.texi (Function Attributes): Document always_inline
        attribute.
        Update documentation about inlining when not optimizing.

        * cp/decl.c (duplicate_decls): Merge always_inline attribute.

        * cp/tree.c (cp_cannot_inline_tree_fn): Do not inline at -O0
        unless DECL_ALWAYS_INLINE.

        * c-objc-common.c (c_cannot_inline_tree_fn): Do not inline at -O0
        unless DECL_ALWAYS_INLINE.
        (c_disregard_inline_limits): Disregard if always_inline set.

        * langhooks.c (lhd_tree_inlining_disregard_inline_limits):
        Disregard if always_inline set.
        (lhd_tree_inlining_cannot_inline_tree_fn): Do not inline at -O0
        unless DECL_ALWAYS_INLINE.

        * attribs.c (handle_always_inline_attribute): New.
        (c_common_attribute_table): Add always_inline.

        * config/rs6000/altivec.h: Add prototypes for builtins
        requiring the always_inline attribute.

From-SVN: r49947

1 files changed, 15 insertions, 5 deletions

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 39e0fb9d260..68d0146bad8 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -1880,7 +1880,8 @@ The keyword @code{__attribute__} allows you to specify special
 attributes when making a declaration.  This keyword is followed by an
 attribute specification inside double parentheses.  The following
 attributes are currently defined for functions on all targets:
-@code{noreturn}, @code{noinline}, @code{pure}, @code{const},
+@code{noreturn}, @code{noinline}, @code{always_inline},
+@code{pure}, @code{const},
 @code{format}, @code{format_arg}, @code{no_instrument_function},
 @code{section}, @code{constructor}, @code{destructor}, @code{used},
 @code{unused}, @code{deprecated}, @code{weak}, @code{malloc}, and
@@ -1946,6 +1947,12 @@ volatile voidfn fatal;
 This function attribute prevents a function from being considered for
 inlining.
 
+@cindex @code{always_inline} function attribute
+@item always_inline
+Generally, functions are not inlined unless optimization is specified.
+For functions declared inline, this attribute inlines the function even
+if no optimization level was specified.
+
 @cindex @code{pure} function attribute
 @item pure
 Many functions have no effects except the return value and their
@@ -3388,10 +3395,13 @@ existing semantics will remain available when @option{-std=gnu89} is
 specified, but eventually the default will be @option{-std=gnu99} and
 that will implement the C99 semantics, though it does not do so yet.)
 
-GCC does not inline any functions when not optimizing.  It is not
-clear whether it is better to inline or not, in this case, but we found
-that a correct implementation when not optimizing was difficult.  So we
-did the easy thing, and turned it off.
+GCC does not inline any functions when not optimizing unless you specify
+the @samp{always_inline} attribute for the function, like this:
+
+@example
+/* Prototype.  */
+inline void foo (const char) __attribute__((always_inline));
+@end example
 
 @node Extended Asm
 @section Assembler Instructions with C Expression Operands