Re: [git patches 1/2] warnings: attack valid cases spotted by warnings

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Roland Dreier wrote:
In this case the code is basically

	u32 x;

	for (n = 0; cond; ++n) {
		...
		if (!n)
			x = something;
		...
	}

	if (n) {
		...
		use(x);
		...
	}

and gcc still warns...

Interestingly, the above accurately describes a common code pattern matching code which caused gcc to emit the uninit'd-var warnings.
For the record I think initializating 'f0' to zero is safer for the 
reasons Linus gave, and in addition, f0 is or'd with a value written to 
a hardware register, which means things should go awry (if they go) in a 
semi-predictable manner.
According to the assembly language produced, sure it is larger -- by one 
(per function) MOV that is adjacent to other initializations, making it 
highly likely the initializations are all streamed together.  I doubt 
one MOV per function will make a huge difference, considering the peace 
of mind it buys.
	Jeff


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