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Description: |
Description: |
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Name: Lal George |
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Date: 2002/03/11 11 22:38:53 EST |
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Tag: george-20020311-jump-chain-elim |
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Description: |
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Tested the jump chain elimination on all architectures (except the |
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hppa). This is on by default right now and is profitable for the |
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alpha and x86, however, it may not be profitable for the sparc and ppc |
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when compiling the compiler. |
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The gc test will typically jump to a label at the end of the cluster, |
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where there is another jump to an external cluster containing the actual |
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code to invoke gc. This is to allow factoring of common gc invocation |
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sequences. That is to say, we generate: |
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f: |
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testgc |
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ja L1 % jump if above to L1 |
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L1: |
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jmp L2 |
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After jump chain elimination the 'ja L1' instructions is converted to |
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'ja L2'. On the sparc and ppc, many of the 'ja L2' instructions may end |
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up being implemented in their long form (if L2 is far away) using: |
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jbe L3 % jump if below or equal to L3 |
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jmp L2 |
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L3: |
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... |
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For large compilation units L2 may be far away. |
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---------------------------------------------------------------------- |
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Name: Matthias Blume |
Name: Matthias Blume |
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Date: 2002/03/11 13:30:00 EST |
Date: 2002/03/11 13:30:00 EST |
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Tag: blume-20020311-mltreeeval |
Tag: blume-20020311-mltreeeval |
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