[PATCH] D124633: [SimplifyLibCalls] Pointers passed to libcalls must point to valid objects

[Martin Sebor via Phabricator via llvm-commits]

msebor added a comment.

Just to confirm your understanding of what GCC does: it relies on attribute `nonnull` on function (and function pointer) declarations to eliminate redundant null pointer tests subsequent to calls to such functions (with `-fdelete-null-pointer-checks`).



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Comment at: llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp:155
 static void annotateNonNullNoUndefBasedOnAccess(CallInst *CI,
-                                         ArrayRef<unsigned> ArgNos) {
+                                         ArrayRef<unsigned> ArgNos, bool MinDereferenceableBytes = 1) {
   Function *F = CI->getCaller();
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It seems that for a `bool` the default ought  to `true` rather than 1 (ditto for the actual argument at the call sites); a better name for the argument would also reflect the fact it's a toggle rather than a count.

But I wonder if changing the last argument to something like `Value *MinBytes = nullptr` and computing the Boolean result from it here would be a way to simplify the code and avoid having to do that at the call site.


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  https://reviews.llvm.org/D124633/new/

https://reviews.llvm.org/D124633