This is on Xcode 2.2.1, GCC 4.0.1. The source code
is quite old and runs on multiple platforms using
other compilers. The following call to SetupParameter
passes in garbage for the pl variable when using the
-Os (fastest/smallest) optimization. Using -O1
optimization works properly.
My question is: is there a compiler flag that we can
use with -Os that will turn off the optimization that
is causing the problem? We'd rather not use only
-O1 optimization. There is likely other
code in our app that will have the same problem.
Thanks.
struct Point {
short v;
short h;
};
...
Point p1;
...
p1.h= 1;
p1.v= 1;
tobj->SetParameter(4110, *(long *) &p1);
output with -Os
--------------------
lwz r9,0(r31)
li r0,1 <--load the 1 into r0
mr r3,r31
li r4,4110
lwz r5,56(r1) <--but here we grab the long 2nd arg for the
SetParameter
sth r0,56(r1) <--before it's really set!
sth r0,58(r1)
lwz r2,48(r9)
mtctr r2
mr r12,r2
bctrl
output with -O1
----------------
li r0,1
sth r0,58(r1) <-- set up pl.h and .v
sth r0,56(r1)
addi r30,r1,56
lwz r2,0(r29)
mr r3,r29
li r4,4110
lwz r5,56(r1) <-- r5 arg gets the 1,1 this time!
lwz r12,48(r2)
mtctr r12
bctrl
