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From: "Marc E. Fiuczynski" <mef@CS.Princeton.EDU>
To: <gcc-help@gcc.gnu.org>
Subject: will gcc support better stack space reuse?
Date: Tue, 12 Jul 2005 03:51:00 -0000	[thread overview]
Message-ID: <NIBBJLJFDHPDIBEEKKLPOEIEFFAA.mef@cs.princeton.edu> (raw)

Hi,

Was wondering whether a new version of GCC for x86 (linux) can now
reallocate unused stack space from locals defined in different scopes.
E.g., functions suck1 and suck2 suffer from increased stack pressure because
gcc (in my case 3.3.3 on linux/x86) cannot smartly reuse the stack space.
Anyone out there with insight on why this is the case and when gcc might
handle stack packing (if not already).

int garray[64];
static inline numberone(int a, int b){
        int array[64];
        array[1]=a*b;
        garray[0]=array[1];
}

static inline numbertwo(int a, int b){
        int array[64];
        array[1]=a*b;
        garray[1]=array[1];
}

void suck1(int a, int b){
        numberone(a,b);
        numbertwo(a,b);
}

void suck2(int a, int b){
        {
        int array[64];
        array[1]=a*b;
        garray[0]=array[1];
        }
        {
        int array[64];
        array[1]=a*b;
        garray[1]=array[1];
        }
}

Marc

                 reply	other threads:[~2005-07-12  3:51 UTC|newest]

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