From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Buck <jbuck@Synopsys.COM>
To: pedwards@ball.com (Edwards, Phil)
Cc: egcs@egcs.cygnus.com, carlo@runaway.xs4all.nl
Subject: Re: Annoying warning
Date: Sun, 11 Apr 1999 18:21:00 -0000
Message-id: <199904120120.SAA16476@atrus.synopsys.com>
References: <B7A6155A71B6D211BB2D0008C7B250B70905CA@daytonmsg.ball.com>
X-SW-Source: 1999-04/msg00392.html

> I mentioned this to the libstdc++-v3 list some time back.  The solution then
> was to simply remove the 'inline' since (according to the list) the egcs
> optimizer doesn't know how to turn tail recursion into a loop. 

That's incorrect: gcc does know how to eliminate tail recursion and has
for a long time.  RMS put that one in years ago: anyone from MIT, where
Scheme rules, wouldn't tolerate a compiler that can't handle tail recursion.

I just confirmed that gcc/egcs correctly transforms and inlines a
tail-recursive function on the Sparc.

Here's my testcase.
---------------------------------
struct node {
    struct node* next;
    int data;
};

inline int last_node(node* p) {
    if (p->next)
	return last_node(p->next);
    else
	return p->data;
}

int call_last_node(node* p) {
    return last_node(p);
}

------------------------

From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joe Buck <jbuck@Synopsys.COM>
To: pedwards@ball.com (Edwards, Phil)
Cc: egcs@egcs.cygnus.com, carlo@runaway.xs4all.nl
Subject: Re: Annoying warning
Date: Fri, 30 Apr 1999 23:15:00 -0000
Message-ID: <199904120120.SAA16476@atrus.synopsys.com>
References: <B7A6155A71B6D211BB2D0008C7B250B70905CA@daytonmsg.ball.com>
X-SW-Source: 1999-04n/msg00395.html
Message-ID: <19990430231500.6I4jPJu3SEPYm8vFJA_aztdkSB-34GEmWa23zWLCemA@z>

> I mentioned this to the libstdc++-v3 list some time back.  The solution then
> was to simply remove the 'inline' since (according to the list) the egcs
> optimizer doesn't know how to turn tail recursion into a loop. 

That's incorrect: gcc does know how to eliminate tail recursion and has
for a long time.  RMS put that one in years ago: anyone from MIT, where
Scheme rules, wouldn't tolerate a compiler that can't handle tail recursion.

I just confirmed that gcc/egcs correctly transforms and inlines a
tail-recursive function on the Sparc.

Here's my testcase.
---------------------------------
struct node {
    struct node* next;
    int data;
};

inline int last_node(node* p) {
    if (p->next)
	return last_node(p->next);
    else
	return p->data;
}

int call_last_node(node* p) {
    return last_node(p);
}

------------------------