[PATCH] D88806: [SCEV] Model ptrtoint(SCEVUnknown) cast not as unknown, but as zext/trunc/self of SCEVUnknown

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri marked an inline comment as done.
lebedev.ri added inline comments.


================
Comment at: llvm/test/Analysis/ScalarEvolution/no-wrap-add-exprs.ll:173
 ; CHECK:  %int.zext = zext i32 %int5 to i64
-; CHECK-NEXT:  -->  (1 + (zext i32 (4 + %int0) to i64))<nuw><nsw> U: [1,4294967294) S: [1,4294967297)
+; CHECK-NEXT:  --> (1 + (zext i32 (4 + (trunc i8* %ptr to i32)) to i64))<nuw><nsw> U: [1,4294967294) S: [1,4294967297)
 
----------------
mkazantsev wrote:
> I don't quite get how we ended up with this. Do we somehow know that `i8*` is wider than `i32`? Is it coming from default data layout or?..
We called `getTruncateOrZeroExtend(OpSCEV, U->getType())` on `%int0 = ptrtoint i8* %ptr to i32`, which is:
```
const SCEV *ScalarEvolution::getTruncateOrZeroExtend(const SCEV *V, Type *Ty,
                                                     unsigned Depth) {
  Type *SrcTy = V->getType();
  assert(SrcTy->isIntOrPtrTy() && Ty->isIntOrPtrTy() &&
         "Cannot truncate or zero extend with non-integer arguments!");
  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
    return V;  // No conversion
  if (getTypeSizeInBits(SrcTy) > getTypeSizeInBits(Ty))
    return getTruncateExpr(V, Ty, Depth);
  return getZeroExtendExpr(V, Ty, Depth);
}
```
, where
```
/// Return the size in bits of the specified type, for which isSCEVable must
/// return true.
uint64_t ScalarEvolution::getTypeSizeInBits(Type *Ty) const {
  assert(isSCEVable(Ty) && "Type is not SCEVable!");
  if (Ty->isPointerTy())
    return getDataLayout().getIndexTypeSizeInBits(Ty);
  return getDataLayout().getTypeSizeInBits(Ty);
}
```

So yes, default datalayout.
Which may mean, we need to hardcode it here in the test.


Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D88806