[PATCH] D103440: [WIP][analyzer] Introduce range-based reasoning for addition operator

[Valeriy Savchenko via Phabricator via cfe-commits]

vsavchenko added inline comments.


================
Comment at: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:1400
+  if (ResultType.isUnsigned()) {
+    LHS.From().uadd_ov(RHS.From(), HasMinOverflowed);
+    LHS.To().uadd_ov(RHS.To(), HasMaxOverflowed);
----------------
manas wrote:
> Using `uadd_ov` (and `sadd_ov`), we can get the added value as well as whether overflow occurred or not. A point is that these functions return `APInt` instead of `APSInt`.
> 
> But when I tried just using:
>   Min = LHS.From().uadd_ov(RHS.From(), HasMinOverflowed);
>   Max = LHS.To().uadd_ov(RHS.From(), HasMaxOverflowed);
> 
> instead of
>   Min = LHS.From() + RHS.From();
>   Max = LHS.To() + RHS.To();
> 
> just for the added value, then the following tests failed (//these tests and all other tests pass when I use the latter method to get Min/Max//):                                                            
>   Clang :: Analysis/PR3991.m
>   Clang :: Analysis/global-region-invalidation.c
>   Clang :: Analysis/malloc-overflow2.c
>   Clang :: Analysis/out-of-bounds-new.cpp
>   Clang :: Analysis/taint-generic.c
> 
> I am working on fixing this part.
You can easily construct `APSInt` from `APInt` using `APSInt ::APSInt(APInt I, bool isUnsigned)` constructor.


Repository:
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  https://reviews.llvm.org/D103440/new/

https://reviews.llvm.org/D103440