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Diffstat (limited to 'content/zettel/1c8.md')
| -rw-r--r-- | content/zettel/1c8.md | 29 |
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diff --git a/content/zettel/1c8.md b/content/zettel/1c8.md new file mode 100644 index 0000000..9997554 --- /dev/null +++ b/content/zettel/1c8.md @@ -0,0 +1,29 @@ ++++ +title = "If-conversion" +author = "Yann Herklotz" +tags = [] +categories = [] +backlinks = ["2b1e", "1c7", "1c2h", "1c", "1b8"] +forwardlinks = ["1b6", "1b8", "1c9"] +zettelid = "1c8" ++++ + +If-conversion is an optimisation which is very common in HLS tools. It +transforms basic blocks ([\#1b6]) that do not contain any loops, into +single hyperblocks ([\#1b8]), which use predicated instructions instead. +However, to support such an optimisation in a verified high-level +synthesis tool, the verification algorithm needs to support SAT checking +of the predicates. It is the conversion that introduces predicated +instructions which can make use of the hyperblocks. It converts +conditional statements into predicated instructions. This transformation +has a few limitations on the kind of conditional statements that it can +translate. First, only conditional statements without loops can be +translated, therefore, one must identify cycles in the control-flow +before performing the if-conversion. Secondly, if-conversion will not +always result in more efficient code, so it should not be applied to any +conditional statements. Instead, it is best applied to conditional +statements where each branch will take a similar amount of time to +execute. + + [\#1b6]: /zettel/1b6 + [\#1b8]: /zettel/1b8 |