NoQ added inline comments.
================
Comment at: lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:511
+ SSE->getLHS()->getType()->isSignedIntegerOrEnumerationType() ||
+ SSE->getLHS()->getType()->isPointerType()) {
+ return negV->Negate(BV, F);
----------------
baloghadamsoftware wrote:
> NoQ wrote:
> > baloghadamsoftware wrote:
> > > NoQ wrote:
> > > > Pointer types are currently treated as unsigned, so i'm not sure you
> > > > want them here.
> > > For me it seems that pointer differences are still pointer types and they
> > > are signed. (The range becomes negative upon negative assumption. From
> > > test `ptr-arith.c`:
> > >
> > > ```
> > > void use_symbols(int *lhs, int *rhs) {
> > > clang_analyzer_eval(lhs < rhs); // expected-warning{{UNKNOWN}}
> > > if (lhs < rhs)
> > > return;
> > > clang_analyzer_eval(lhs < rhs); // expected-warning{{FALSE}}
> > >
> > > clang_analyzer_eval(lhs - rhs); // expected-warning{{UNKNOWN}}
> > > if ((lhs - rhs) != 5)
> > > return;
> > > clang_analyzer_eval((lhs - rhs) == 5); // expected-warning{{TRUE}}
> > > }
> > > ```
> > >
> > > If I put `clang_analyzer_printState()` into the empty line in the middle,
> > > I get the following range for the difference: `[-9223372036854775808,
> > > 0]`. If I replace `int*` with `unsigned`, this range becomes `[0, 0]`, so
> > > `int*` is handled as a signed type here.
> > Umm, yeah, i was wrong.
> >
> > *looks closer*
> >
> > `T` is the type of the difference, right? I don't think i'd expect pointer
> > type as the type of the difference.
> >
> > Could you add test cases for pointers if you intend to support them (and
> > maybe for unsigned types)?
> I do not know exactly the type, but if I remove the `T->isPointerType()`
> condition the test in `ptr_arith.c` will fail with `UNKNOWN`. So the type of
> the difference is a type that returns `true` from `T->isPointerType()`.
>
> Pointer tests are already there in `ptr_arith.c`. Should I duplicate them?
I don't see any failing tests when i remove `T->isPointerType()`.
Also this shouldn't be system-specific, because the target triple is hardcoded
in `ptr-arith.c` runline.
Could you point out which test is failing and dump the type in question
(`-ast-dump`, or `Type->dump()`, or `llvm::errs() << QualType::getAsString()`,
or whatever)?
https://reviews.llvm.org/D35110
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