search for: alias_

...e C language does not provide > > semantics that allow the final inference above. It is conceivable that > > `x1 != x2, y1 != y2`, but the indices do actually alias, since > > according to C semantics, the two indices alias if the _flattened > > representation of the indices alias_. Consider the parameter > > values: > > > > ``` > > n = m = 3 > > x1 = 1, y1 = 0; B[x1][y1] = nx1+y1 = 3*1+0=3 > > x2 = 0, y2 = 3; B[x2][y2] = nx2+y2 = 3*0+3=3 > > ``` > > > > Hence, the array elements `B[x1][y1]` and `B[x2][y2]` _can alias_, an...

...However, alas, this is illegal, for the C language does not provide semantics that allow the final inference above. It is conceivable that `x1 != x2, y1 != y2`, but the indices do actually alias, since according to C semantics, the two indices alias if the _flattened representation of the indices alias_. Consider the parameter values: ``` n = m = 3 x1 = 1, y1 = 0; B[x1][y1] = nx1+y1 = 3*1+0=3 x2 = 0, y2 = 3; B[x2][y2] = nx2+y2 = 3*0+3=3 ``` Hence, the array elements `B[x1][y1]` and `B[x2][y2]` _can alias_, and so the transformation proposed in `ex1_opt` is unsound in general. In contrast, many...

...r the C language does not provide >> semantics that allow the final inference above. It is conceivable that >> `x1 != x2, y1 != y2`, but the indices do actually alias, since >> according to C semantics, the two indices alias if the _flattened >> representation of the indices alias_. Consider the parameter >> values: >> >> ``` >> n = m = 3 >> x1 = 1, y1 = 0; B[x1][y1] = nx1+y1 = 3*1+0=3 >> x2 = 0, y2 = 3; B[x2][y2] = nx2+y2 = 3*0+3=3 >> ``` >> >> Hence, the array elements `B[x1][y1]` and `B[x2][y2]` _can alias_, and >&gt...

...r the C language does not provide > semantics that allow the final inference above. It is conceivable that > `x1 != x2, y1 != y2`, but the indices do actually alias, since > according to C semantics, the two indices alias if the _flattened > representation of the indices alias_. Consider the parameter > values: > > ``` > n = m = 3 > x1 = 1, y1 = 0; B[x1][y1] = nx1+y1 = 3*1+0=3 > x2 = 0, y2 = 3; B[x2][y2] = nx2+y2 = 3*0+3=3 > ``` > > Hence, the array elements `B[x1][y1]` and `B[x2][y2]` _can alias_, and > so the...

...does not provide >>> semantics that allow the final inference above. It is conceivable that >>> `x1 != x2, y1 != y2`, but the indices do actually alias, since >>> according to C semantics, the two indices alias if the _flattened >>> representation of the indices alias_. Consider the parameter >>> values: >>> >>> ``` >>> n = m = 3 >>> x1 = 1, y1 = 0; B[x1][y1] = nx1+y1 = 3*1+0=3 >>> x2 = 0, y2 = 3; B[x2][y2] = nx2+y2 = 3*0+3=3 >>> ``` >>> >>> Hence, the array elements `B[x1][y1]` and...

...gt; > semantics that allow the final inference above. It is conceivable that > > > `x1 != x2, y1 != y2`, but the indices do actually alias, since > > > according to C semantics, the two indices alias if the _flattened > > > representation of the indices alias_. Consider the parameter > > > values: > > > > > > ``` > > > n = m = 3 > > > x1 = 1, y1 = 0; B[x1][y1] = nx1+y1 = 3*1+0=3 > > > x2 = 0, y2 = 3; B[x2][y2] = nx2+y2 = 3*0+3=3 > > > ``` > > > > > >...