[PATCH] deprecate -finline-limit and make it an optimization option (PR 84603)

[Martin Sebor <msebor at gmail dot com>]

While testing my recent changes to the handling of attributes
on C++ templates I noticed that the -finline-limit=N option
is not recognized in attribute or pragma optimize.  In response
to the bug I raised, Richard you said the option is deprecated,
so I went ahead and documented the deprecation in the manual
and also added a deprecation warning.  I also added it to
Optimization options.  The attached patch reflects these
changes.

I also tried to put together a test to verify that the option
works as expected, both in attributes and in pragmas.  I wasn't
able to get it to work reliably or sensibly.

In C, #pragma optimize ("inline-limit=1") has a global effect
on all functions in the file, even those lexically before the
pragma.  In C++, the pragma has no effect.  Both of these
effects are contrary to my reading of the manual.

Attribute optimize ("inline-limit") behaves similarly, which
seems even more unexpected and even more contrary to the manual
which by referring to Function Specific Option Pragmas suggests
that both the pragma and especially the attribute apply
optimizations to just the functions they're specified for.

I don't expect this to be news to anyone here or easily fixable,
but I think the effects or limitations of the mechanism should
be made clear in the manual.  Ditto for #pragma GDD diagnostic
and its effect on middle-end warnings (or lack thereof).  With
the increasing number of such warnings that's increasingly
becoming a source of frustration for users.  If you agree I'll
put together a documentation patch to try to clarify this.

Martin

PR middle-end/84603 -  -finline-limit not accepted in attribute and #pragma optimize

gcc/testsuite/ChangeLog:

	PR middle-end/84603
	* gcc.dg/inline-40.c: New test.

gcc/ChangeLog:

	PR middle-end/84603
	* common.opt (-finline-limit): Add to Optimization options.  Add
	deprecation warning.
	* doc/invoke.texi: Document deprecation.

Index: gcc/common.opt
===================================================================
--- gcc/common.opt	(revision 258114)
+++ gcc/common.opt	(working copy)
@@ -1621,7 +1621,7 @@ finline-limit-
 Common RejectNegative Joined Alias(finline-limit=)
 
 finline-limit=
-Common RejectNegative Joined UInteger
+Common RejectNegative Joined UInteger Optimization Warn(%<-finline-limit%> is deprecated; use %<--param%> instead)
 -finline-limit=<number>	Limit the size of inlined functions to <number>.
 
 finline-atomics
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi	(revision 258114)
+++ gcc/doc/invoke.texi	(working copy)
@@ -7854,6 +7854,8 @@ in default behavior.
 abstract measurement of function's size.  In no way does it represent a count
 of assembly instructions and as such its exact meaning might change from one
 release to an another.
+@code{-finline-limit} is deprecated in favor of
+the corresponding @option{--param @var{name}=@var{value}} options.
 
 @item -fno-keep-inline-dllexport
 @opindex fno-keep-inline-dllexport
Index: gcc/testsuite/gcc.dg/inline-40.c
===================================================================
--- gcc/testsuite/gcc.dg/inline-40.c	(nonexistent)
+++ gcc/testsuite/gcc.dg/inline-40.c	(working copy)
@@ -0,0 +1,19 @@
+/* PR middle-end/84603 - -finline-limit not accepted in attribute
+   and #pragma optimize
+   { dg-do compile }
+   { dg-options "-Wall" }  */
+
+/* Verify that the options are accepted in both pragmas and attributes.  */
+#pragma GCC optimize ("inline-functions")
+void f0 (void);
+
+#pragma GCC optimize ("inline-limit=32")  /* { dg-bogus "bad option .-finline-limit=32." } */
+void f1 (void);
+
+void __attribute__ ((optimize ("inline-functions")))
+f2 (void);
+
+void __attribute__ ((optimize ("inline-limit=100")))   /* { dg-bogus "bad option .-finline-limit=100." } */
+f3 (void);
+
+