mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-01-21 19:32:16 +00:00
667d4b8de6
and extern_weak_odr. These are the same as the non-odr versions, except that they indicate that the global will only be overridden by an *equivalent* global. In C, a function with weak linkage can be overridden by a function which behaves completely differently. This means that IP passes have to skip weak functions, since any deductions made from the function definition might be wrong, since the definition could be replaced by something completely different at link time. This is not allowed in C++, thanks to the ODR (One-Definition-Rule): if a function is replaced by another at link-time, then the new function must be the same as the original function. If a language knows that a function or other global can only be overridden by an equivalent global, it can give it the weak_odr linkage type, and the optimizers will understand that it is alright to make deductions based on the function body. The code generators on the other hand map weak and weak_odr linkage to the same thing. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66339 91177308-0d34-0410-b5e6-96231b3b80d8
*** add gcc builtins for alpha instructions *** custom expand byteswap into nifty extract/insert/mask byte/word/longword/quadword low/high sequences *** see if any of the extract/insert/mask operations can be added *** match more interesting things for cmovlbc cmovlbs (move if low bit clear/set) *** lower srem and urem remq(i,j): i - (j * divq(i,j)) if j != 0 remqu(i,j): i - (j * divqu(i,j)) if j != 0 reml(i,j): i - (j * divl(i,j)) if j != 0 remlu(i,j): i - (j * divlu(i,j)) if j != 0 *** add crazy vector instructions (MVI): (MIN|MAX)(U|S)(B8|W4) min and max, signed and unsigned, byte and word PKWB, UNPKBW pack/unpack word to byte PKLB UNPKBL pack/unpack long to byte PERR pixel error (sum accross bytes of bytewise abs(i8v8 a - i8v8 b)) cmpbytes bytewise cmpeq of i8v8 a and i8v8 b (not part of MVI extentions) this has some good examples for other operations that can be synthesised well from these rather meager vector ops (such as saturating add). http://www.alphalinux.org/docs/MVI-full.html