From: "Günter Reusing" <guenter DOT reusing AT web DOT de>
Newsgroups: comp.os.msdos.djgpp
Subject: Optimization
Date: Wed, 18 Sep 2002 00:33:19 +0200
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

Can anyone help on optimization of C++ code.
With -O3 and all other optimization options I tried I'm stuck with redundant
code.
A typical example (output after compiler and assembler run) :

/APP
    fsincos
/NO_APP
    sall $3, %ecx
    movl (%eax), %esi
*     fsts -56(%ebp)
    fxch %st(1)
**     fsts -52(%ebp)
    addl %ecx, %esi
*     movl -56(%ebp), %eax
**     movl -52(%ebp), %ebx
**     movl %ebx, 4(%esi)
*     movl %eax, (%esi)
    movl 8(%ebp), %eax
    leal 0(,%edi,8), %ebx
    fld %st(1)
    fxch %st(1)

The lines marked with * repective ** show unneccesarry redundant moves.
Which options can solve that?