Changes between Version 20 and Version 21 of Commentary/Compiler/Backends/LLVM/Alias


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Timestamp:
Jan 23, 2012 7:29:06 PM (3 years ago)
Author:
dterei
Comment:

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  • Commentary/Compiler/Backends/LLVM/Alias

    v20 v21  
    9797 
    9898== Problems / Optmisations to Solve == 
     99 
     100=== LLVM Optimisations === 
     101 
     102Roman reported that running 'opt -std-compile-opts' gives much better code than running 'opt -O3'. 
     103 
     104'''Following is from Roman Leschinskiy''' 
     105 
     106'-O2 -std-compile-opts' does the trick but it's obviously overkill because 
     107it essentially executes the whole optimisation pipeline twice. The crucial 
     108passes seem to be loop rotation and loop invariant code motion. These are 
     109already executed twice by -O2 but it seems that they don't have enough 
     110information then and that something interesting happens in later passes 
     111which allows them to work much better the third time. 
    99112 
    100113=== Safe Loads (speculative load) ===