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Original bug ID: 5795 Reporter:@chambart Assigned to:@lefessan Status: closed (set by @xavierleroy on 2015-12-11T18:19:32Z) Resolution: fixed Priority: normal Severity: feature Version: 4.00.1 Fixed in version: 4.01.0+dev Category: back end (clambda to assembly) Related to:#6020 Monitored by:@hcarty
Bug description
The sqrt function can be optimised by calling directly the processor instruction, avoiding a call.
Has anyone done any performance comparison? I'm curious about the performance gains to be expected, to see if it's worth the trouble extending the 32-bit (x87) backend as well (this backend is still very much useful for Windows...).
As far as I know the x87 backend is already doing that.
But only if -ffast-math is selected. Not using "fsin", "fcos", etc by default is justified because those instructions are not quite 100% IEEE754 compliant. But it could make sense to always generate "fsqrt" since, AFAIK, this instruction implements proper IEEE754 behavior. This would have the advantage of working around bugs in Win32 CRT's sqrt() function, cf. #6020.
Original bug ID: 5795
Reporter: @chambart
Assigned to: @lefessan
Status: closed (set by @xavierleroy on 2015-12-11T18:19:32Z)
Resolution: fixed
Priority: normal
Severity: feature
Version: 4.00.1
Fixed in version: 4.01.0+dev
Category: back end (clambda to assembly)
Related to: #6020
Monitored by: @hcarty
Bug description
The sqrt function can be optimised by calling directly the processor instruction, avoiding a call.
Additional information
The patch was not tested on windows
File attachments
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