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On 13 Aug 2002, H. Peter Anvin wrote: >... > > > Because the compiler sees: > > > > > > for (i = 0; i < N; i++) > > > ; > > > > > > and it says "ah ha. A busy wait delay loop" and leaves it alone. > > > > > > It's actually a special-case inside the compiler to not optimise > > > away such constructs. > > > > Why is this a special case? As long as a compiler can't prove that the > > computed value of i isn't used later it mustn't optimize it away. > > Bullsh*t. It can legitimately transform it into: > > i = N; >... Ah, my misunderstanding: "optimize away" didn't mean "completely remove it" but "transform it to something semantically equivalent". > -hpa Thanks Adrian -- You only think this is a free country. Like the US the UK spends a lot of time explaining its a free country because its a police state. Alan Cox - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
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