[llvm-commits] [llvm] r70270 - in /llvm/trunk: include/llvm/CodeGen/ include/llvm/Target/ lib/CodeGen/ lib/CodeGen/AsmPrinter/ lib/CodeGen/SelectionDAG/ lib/Target/ARM/ lib/Target/ARM/AsmPrinter/ lib/Target/Alpha/ lib/Target/Alpha/AsmPrinter/ lib

Evan Cheng evan.cheng at apple.com
Tue Jun 2 13:59:24 PDT 2009


On Jun 2, 2009, at 10:32 AM, Devang Patel wrote:

> On Mon, Apr 27, 2009 at 5:21 PM, Bill Wendling <isanbard at gmail.com>  
> wrote:
>> Author: void Date: Mon Apr 27 19:21:31 2009 New Revision: 70270 URL:
>> http://llvm.org/viewvc/llvm-project?rev=70270&view=rev Log: Massive  
>> check in. This
>> changes the "-fast" flag to "-O#" in llc. If you want to use the  
>> old behavior, the flag is -O0.
>> This change allows for finer-grained control over which  
>> optimizations are run at different -O
>> levels. Most of this work was pretty mechanical. The majority of  
>> the fixes came from verifying
>> that a "fast" variable wasn't used anymore. The JIT still uses a  
>> "Fast" flag. I'm not 100% sure
>> if it's necessary to change it there...
>
> We won't to encode this info in bit code and avoid globals like this.
> We already use a function attribute for -Os. Why not do the same here
> ?

This controls what codegen passes are being run. It's done once for  
the whole compilation. Function notes are for finer grain control that  
tell these passes to "behave" differently for individual functions.  
Yes, we could use function notes to control optimization level for  
individual functions. But I view that as a different issue.

Evan

> -
> Devang
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