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Beginner
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Code optimizations but small binary file

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Can i combine /Ox with /Os option?

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Valued Contributor II
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>>...In my experience, for Qt based program, if you set >> -fno-exceptions -fno-inline >>it will help reducing executable size significantly. . Another option to consider is a 'hand-based' code optimization. On some projects developers simply do not care how many C/C++ code lines they have and some simple algorithms look like monsters ( thousands of lines instead of hundreds lines ).

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Black Belt
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I suspect, if you set both options, the latter one will suppress the first. /Os for ICL was documented as generating the minimum size binary with no effort to gain performance. /O1 would produce a slightly larger binary with most performance optimizations, except for auto-vectorization.
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Valued Contributor II
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Hi everybody, >>...Can i combine /Ox with /Os option? No and this is because /Ox ( Full Optimization ) will override any other optimization option /On. It is very easy to verify and a warning message, like: '...overriding '/O1' with '/Ox'', should be displayed. Best regards, Sergey
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Beginner
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There are my test small program written on Qt 4: /Os = 104 kb /O2 = 114 kb /O2 /Os = 105 kb /Os /O2 = 105 kb /O3 = 114 kb /O3 /Os = 105 kb /Os /O3 = 105 kb /Ox = 116 kb /Ox /Os = 112 kb /Os /Ox = 112 kb
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Beginner
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Sergey Kostrov wrote:

Hi everybody,

>>...Can i combine /Ox with /Os option?

No and this is because /Ox ( Full Optimization ) will override any other optimization option /On. It is very easy to verify and a warning message, like: '...overriding '/O1' with '/Ox'', should be displayed.

Best regards,
Sergey

C:\Qt\qt-everywhere-opensource-src-4.8.3\examples\widgets\stylesheet>icl Intel(R) C++ Compiler XE for applications running on IA-32, Version 13.0.0.089 Build 20120731 In the course of the test (see results above) I have not received such messages

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Valued Contributor II
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[SergeyK] I understood that you're on a Windows platform and here is a quote from 'Intel C++ compiler User and Reference Guides': ... __ NOTE. On Windows systems, the /Od option is part of a mutually-exclusive group of __ options that includes /Od, /O1, /O2, /O3, and /Ox. The last of any of these options __ specified on the command line will override the previous options from this group. ... [SergeyK] Please take a look at the document ( pdf or online ) because it has lots of details. For example, like: ... __ The compiler enables maximum optimizations by combining the following options: __ • /Ob2 __ • /Og __ • /Oy __ • /Ot __ • /Oi ... [SergeyK] In case of '/Os' option the document says: ... This option enables optimizations that do not increase code size and produces smaller code size than O2. It disables some optimizations that increase code size for a small speed benefit. This option tells the compiler to favor transformations that reduce code size over transformations that produce maximum performance. ...
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Beginner
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In my experience, for Qt based program, if you set -fno-exceptions -fno-inline it will help reducing executable size significantly.
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Valued Contributor II
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>>...In my experience, for Qt based program, if you set >> -fno-exceptions -fno-inline >>it will help reducing executable size significantly. . Another option to consider is a 'hand-based' code optimization. On some projects developers simply do not care how many C/C++ code lines they have and some simple algorithms look like monsters ( thousands of lines instead of hundreds lines ).

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