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| From: | Philippe Mathieu-Daudé |
| Subject: | Re: [Qemu-devel] [Qemu-arm] [PATCH 3/3] hw/misc/exynos4210_pmu: Reorder local variables for readability |
| Date: | Mon, 6 Mar 2017 10:34:29 -0300 |
| User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 |
On 03/06/2017 10:16 AM, Peter Maydell wrote:
On 6 March 2017 at 13:03, Paolo Bonzini <address@hidden> wrote:On 06/03/2017 10:46, Peter Maydell wrote:On 6 March 2017 at 04:06, Philippe Mathieu-Daudé <address@hidden> wrote:your change seems OK but while you are here, 'unsigned' is considered harmful since more than a decade.Considered harmful by who, and why?
sorry to cry wolf :)
It is true that unsigned has all the disadvantages of "int" (it may be smaller than the size of the object" and all the disadvantages of "size_t" (it doesn't optimize as well because the compiler cannot exploit undefined behavior). I wouldn't call it harmful, but it feels like the worst of both worlds.size_t is a pretty silly choice for a variable that's looping through the number of registers in the device, which is a value that would fit in 16 bits, let alone 32. I would probably have written this with 'int', but use of 'unsigned' doesn't come very high up on my list of things to complain about.
silly would be "typeof(PMU_NUM_OF_REGISTERS) i;" :p I got your point about the complain priority list.
(since we use -fwrapv the compiler can't exploit undefined behaviour for signed loop indexes either.)
regards, Phil.
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