Simplify and apply field sensitivity before value-set-deref #4949
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This means that any member-of-symbol constructs introduced by a nested dereference, such as x->y ==> (x == &o1 ? o1 : o2).y, can be simplified to produce e.g. (x == &o1 ? o1.y : o2.y) ==> (x == &o1 ? o1..y : o2..y). value_set_dereferencet will then special-case the if-expression, dereferencing the inner o1..y and o2..y individually. In the best case where each has a single possible alias, &o3 and &o4 respectively, we end up with (x == &o1 ? &o3 : &o4), rather than the current result: let p = (x == &o1 ? o1 : o2).y in (p == &o3 ? o3 : o4)
smowton
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peterschrammel and
tautschnig
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peterschrammel
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Jul 25, 2019
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✔️
Passed Diffblue compatibility checks (cbmc commit: 8ff8927).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/120726270
Codecov Report
@@ Coverage Diff @@
## develop #4949 +/- ##
===========================================
+ Coverage 69.27% 69.27% +<.01%
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Files 1307 1307
Lines 108143 108145 +2
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+ Hits 74916 74918 +2
Misses 33227 33227
Continue to review full report at Codecov.
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owen-mc-diffblue
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This means that any member-of-symbol constructs introduced by a nested dereference,
such as
x->y ==> (x == &o1 ? o1 : o2).y, can be simplified to produce e.g.(x == &o1 ? o1.y : o2.y) ==> (x == &o1 ? o1..y : o2..y). value_set_dereferencet willthen special-case the if-expression, dereferencing the inner
o1..yando2..yindividually.In the best case where each has a single possible alias,
&o3and&o4respectively, weend up with
(x == &o1 ? &o3 : &o4), rather than the current result:let p = (x == &o1 ? o1 : o2).y in (p == &o3 ? o3 : o4).The net benefit: smaller expressions, and thanks to simpler expressions a higher chance that future simplification will succeed.