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Thumb optimization question
- From: "Ivan Petrov" <ivan_p at seculab dot ru>
- To: <gcc at gcc dot gnu dot org>
- Date: Tue, 27 Dec 2005 02:41:30 +0500
- Subject: Thumb optimization question
I have one question. So... have small sample programm.
[code]
int bar( int );
int foo( int a, int b )
{
return bar( a + b );
}
[/code]
If I compille it with out -thumb parameter, i have very clean code.
add r0, r1, r0
bx lr
But with -thumb parameter have unopimized code.
add r1, r1, r0
mov r0, r1
bx lr
All diff of it outrage on '*.27.combine' (key -da) optimization step. But I long time can't understad how it work.
Can anybody help me with it?
--
Regards, Ivan