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Gcc cannot to preview the contents of "if{ ... }". |
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In this case there is a single instruction, but in |
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others cases the if statement can contain a lot of |
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instructions. |
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The I think gcc deals the "if" mechanically, and it |
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don't look for particular "if" with one istruction as |
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in your example. |
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After that, there is not a flag or a special |
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opitmization that favourite use of cmov in asm code, |
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cmov it's only a instruction.Than you can use it |
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"manually" in inline assembler. |
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|
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--- Paul Ingelbrant <pi@×××××.se> ha scritto: > |
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Quoting Andrea Pretto <prettz_it@×××××.it>: |
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> |
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> > The flag -mmmx ( like -msse -m3dnow etc...) |
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> activate |
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> > some extensions for C language. |
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> > |
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> > See this: |
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> > |
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> |
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http://gcc.gnu.org/onlinedocs/gcc-3.3.3/gcc/X86-Built-in-Functions.html#X86%20Built-in%20Functions |
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> > |
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> > So, those flag activate these built-in functions. |
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> |
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> I see. |
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> |
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> But what's the matter with the cmov instruction? |
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> Should be reasonably "simple" |
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> for gcc to use it automatically... |
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> |
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> -- |
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> gentoo-performance@g.o mailing list |
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> |
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