[PATCH] D68089: [InstCombine] Optimize some memccpy calls to memcpy/null

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

(Comments using argument names from the signature `void *memccpy(void *dest, const void *src, int c, size_t n);`.)

Please add a testcase where the optimization triggers and "c" is 0.  (I think getConstantStringInfo trims the null terminator by default?)

It should be possible to optimize cases where "c" doesn't appear in "src" if "n" is smaller than the length of "src".



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Comment at: test/Transforms/InstCombine/memccpy.ll:57
+; CHECK-LABEL: @memccpy_to_null3(
+; CHECK-NEXT:    ret i8* null
+;
----------------
This is obviously wrong; you've removed the side-effect.


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