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+title = "Main simple explanation of GSA construction"
+author = "Yann Herklotz"
+tags = []
+categories = []
+backlinks = ["2e1b1a"]
+forwardlinks = ["3a8"]
+zettelid = "2e1b1b"
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+
+The main explanation is quite simple, however, the details are not that
+easy. Once one has constructed SSA with φ functions, the translation to
+GSA is as follows:
+
+-   Loops have to be identified, and these are normalised using
+    pre-header (PH), post-body (PB), post-exit (PE) nodes, which in the
+    case of CompCertSSA ([\#3a8]), means that these are populated with
+    extra Inop instructions.
+-   Then, PH nodes are populated with μ functions, and for each variable
+    that has a μ function assignment we also generate a η function
+    assignments for those variables.
+-   Finally, the other φ functions are replaced by γ functions, where
+    the predicate needs to be found first.
+
+  [\#3a8]: /zettel/3a8