https://bugs.kde.org/show_bug.cgi?id=385843
--- Comment #5 from Ivo Raisr <iv...@ivosh.net> --- Your fix touches register allocation. It is crucial that both ARMInstr_Call() and getRRegUniverse_ARM() are kept in sync (hinted in getRRegUniverse_ARM as well) and that register allocator is presented with the workable set of registers. By marking all Q ones as caller saved (trashed for call), register allocator would need to spill them all before the call. This creates a performance penalty and bloats the generated r-code. Would you try running Memcheck on a program which uses 128-bit VFP (q) registers with '--stats=yes' and note the difference on 'ratio' reported? How prevalent are programs utilizing 128-bit VFP registers compared to 64-bit ones? In other words, are compilers (gcc) likely to utilize those registers a lot? A clue for your answer might lie in the document you cited first: "Registers s16-s31 (d8-d15, q4-q7) must be preserved across subroutine calls; registers s0-s15 (d0-d7, q0-q3) do not need to be preserved (and can be used for passing arguments or returning results in standard procedure-call variants). Registers d16-d31 (q8-q15), if present, do not need to be preserved." -- You are receiving this mail because: You are watching all bug changes.
