Backport "[analyzer] Unroll loops of compile-time upper-bounded loops" #11980
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Previously, only literal upper-bounded loops were recognized. This patch relaxes this matching to accept any compile-time deducible constant expression. It would be better to rely on the SVals (values from the symbolic domain), as those could potentially have more accurate answers, but this one is much simpler. Note that at the time we calculate this value, we have not evaluated the sub-exprs of the condition, consequently, we can't just query the Environment for the folded SVal. Because of this, the next best tool in our toolbox is comp-time evaluating the Expr. rdar://165363923 (cherry picked from commit 17b19c5)
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@swift-ci please test |
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Previously, only literal upper-bounded loops were recognized. This patch relaxes this matching to accept any compile-time deducible constant expression.
It would be better to rely on the SVals (values from the symbolic domain), as those could potentially have more accurate answers, but this one is much simpler.
Note that at the time we calculate this value, we have not evaluated the sub-exprs of the condition, consequently, we can't just query the Environment for the folded SVal.
Because of this, the next best tool in our toolbox is comp-time evaluating the Expr.
rdar://165363923
(cherry picked from commit 17b19c5)