Make Argument::getArgNo() constant time, not O(#args)
getArgNo is actually hot in LLVM, because its how we check for
attributes on arguments:
bool Argument::hasNonNullAttr() const {
if (!getType()->isPointerTy()) return false;
if (getParent()->getAttributes().
hasAttribute(getArgNo()+1, Attribute::NonNull))
return true;
It actually shows up as the 23rd hottest leaf function in a 13s sample
of LTO of llc.
This grows Argument by four bytes, but I have another pending patch to
shrink it by removing its ilist_node base.
Reviewed By: chandlerc
Subscribers: inglorion, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D31057
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298003
91177308-0d34-0410-b5e6-
96231b3b80d8