Re: Question on compiler warning

From: Mark Cave-Ayland
Date: Tue Dec 31 2013 - 06:18:54 EST

On 31/12/13 01:24, Larry Finger wrote:

In his regular article entitled Build regressions/improvements in
Geert Uytterhoeven reports the following warning regression:

+ /scratch/kisskb/src/drivers/net/wireless/b43/phy_n.c: warning:
'val_addr' may be used uninitialized in this function [-Wuninitialized]:
=> 178:21

This warning does not show up on any of my compilers, and it should not
as the initialization and usage of that variable both take place in
conditional branches that are testing exactly the same pointer.

Hi Larry,

Could it be that you don't see the issue the locally because you've got different compiler optimisation settings? I've seen a similar bug recently on another project where the "may be used uninitialized" warning appears with -O0 and -O1 but magically disappears with the default -O2 setting (presumably because the optimiser performs some kind of inlining/reordering that makes the issue go away).


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