[clang] [clang][dataflow] Factor out built-in boolean model into an explicit module. (PR #82950)

[Yitzhak Mandelbaum via cfe-commits]

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@@ -1059,9 +1066,16 @@ void Environment::assume(const Formula &F) {
   DACtx->addFlowConditionConstraint(FlowConditionToken, F);
 }
 
+#if 0
 bool Environment::proves(const Formula &F) const {
   return DACtx->flowConditionImplies(FlowConditionToken, F);
 }
+#else
+bool Environment::proves(const Formula &F) const {
+  auto V = simple_bool_model::getLiteralValue(F, *this);
+  return V.has_value() && *V;
+}
+#endif
 
 bool Environment::allows(const Formula &F) const {
   return DACtx->flowConditionAllows(FlowConditionToken, F);
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ymand wrote:

Yes, but not to `proves`: it should be `value_or(true)` -- that is, if we lack any definite setting, we "allow" it to be anything.

https://github.com/llvm/llvm-project/pull/82950