One of the main points of for loops is that you can safety check the
length once, before entering the loop, and then safely assume that every
element inside the loop is in bounds.
In master branch, the safety checks are incorrectly intact even inside
for loops. This commit fixes it. It's especially nice with multi-object
loops because the number of elided checks is N * M where N is how many
iterations and M is how many objects.
These functions are currently footgunny when working with pointers to
arrays and slices. They just return the stated length of the array/slice
without iterating and looking for the first sentinel, even if the
array/slice is a sentinel terminated type.
From looking at the quite small list of places in the standard
library/compiler that this change breaks existing code, the new code
looks to be more readable in all cases.
The usage of std.mem.span/len was totally unneeded in most of the cases
affected by this breaking change.
We could remove these functions entirely in favor of other existing
functions in std.mem such as std.mem.sliceTo(), but that would be a
somewhat nasty breaking change as std.mem.span() is very widely used for
converting sentinel terminated pointers to slices. It is however not at
all widely used for anything else.
Therefore I think it is better to break these few non-standard and
potentially incorrect usages of these functions now and at some later
time, if deemed worthwhile, finally remove these functions.
If we wait for at least a full release cycle so that everyone adapts to
this change first, updating for the removal could be a simple find and
replace without needing to worry about the semantics.
- cbe: Implement linksection support, to support TLS when not linking libc
- cbe: Support under-aligned variables / struct fields
- cbe: Support packed structs (in the C definition of packed)
- windows: Fix regression with x86 _tls_array
- compiler_rt: Add 128-bit atomics to compiler_rt
- tests: Re-enable threadlocal tests on cbe+windows, and llvm+x86
- tests: Re-enable f80 tests that now pass
- ci: change windows ci to run the CBE behaviour tests with -lc, to match how the compiler is bootstrapped
- update zig1.wasm
@bitCast from integer NaN representation to float NaN resulted in
changed bits in float. This only happened with signaled NaN.
- added test for signaled NaN
- added tests for quiet NaN (for completeness)
closes#14198
