[llvm-commits] [PATCH] simplify-libcalls: fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0

[Benjamin Kramer]

This seems to be a common idiom to check the prefix of a string (lldb uses it) and it triggers O(n*m) behavior in most libc implementations. strncmp brings it down to O(m).

I'm not sure if simplify-libcalls is the right place for this. The code basically works around the pass's infrastructure (skipping statistics etc.)


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