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Re: [PATCH] Pass -mtune and -march options to assembler.
Mark Mitchell <mark@codesourcery.com> wrote:
What optimization is the assembler doing? In general,
we want the compiler doing the optimization; c.f., MIPS.
Unfortunately, it's not possible to do all optimizations
on compiler level.
Some optimizations are impossible without exact knowledge
of
address and opcodes.
One example avoiding of branch mispredicts -
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39942
Other example - Ensure instructions using 0xF7 opcode byte
does not start at
offset 14 of a fetch line...
Loop optimization is dependanle from size of loop too.
GNU AS support only "different processors have better nops
for different sizes", now.
Vladimir
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