Yes yes, the spec says compilers are free to do whatever they want. That doesn’t mean they should.

> The user didn’t initialize this integer. Let’s assume it’s always 4 since that helps us optimize this division over here into a shift…

This is convenient for who exactly? Why not just treat it as a black box memory load and not do further “optimizations”?

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masklinn 9 hours ago | parent [-]

> That doesn’t mean they should.

Nobody’s stopping you from using non-optimising compilers, regardless of the strawmen you assert.

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foltik 9 hours ago | parent [-]

As if treating uninitialized reads as opaque somehow precludes all optimizations?

There’s a million more sensible things that the compiler could do here besides the hilariously bad codegen you see in the grandparent and sibling comments.

All I’ve heard amounts to “but it’s allowed by the spec.” I’m not arguing against that. I’m saying a spec that incentivizes this nonsense is poorly designed.

	▲	Negitivefrags 5 hours ago \| parent [-]
		Why is the code gen bad? What result are you wanting? You specifically want whatever value happened to be on the stack as opposed to a value the compiler picked?