If nonnull is already set, we currently skip setting both nonnull
and dereferenceable. Make these independent, to avoid regressions
when additional nonnull attributes are inferred earlier.
There's a potential change in dereferenceability attribute semantics in the nearish future. See llvm-dev thread "RFC: Decomposing deref(N) into deref(N) + nofree" and D99100 for context.
This change simply adds appropriate attributes to tests to keep transform logic exercised under both old and new/proposed semantics. Note that for many of these cases, O3 would infer exactly these attributes on the test IR.
This change handles the idiomatic pattern of a dereferenceable object being passed to a call which can not free that memory. There's a couple other tests which need more one-off attention, they'll be handled in another change.
- When emitting libcalls, do not only pass the calling convention from the
function prototype but also the attributes.
- Do not pass attributes from e.g. libc memcpy to llvm.memcpy.
Review: Reid Kleckner, Eli Friedman, Arthur Eubanks
Differential Revision: https://reviews.llvm.org/D103992
I think we can use here same logic as for nonnull.
strlen(X) - X must be noundef => valid pointer.
for libcalls with size arg, we add noundef only if size is known and greater than 0 - so pointers must be noundef (valid ones)
Reviewed By: jdoerfert, aqjune
Differential Revision: https://reviews.llvm.org/D95122
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
