https://llvm.org/bugs/show_bug.cgi?id=1388
John Brawn <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |[email protected] Resolution|--- |FIXED --- Comment #7 from John Brawn <[email protected]> --- This was fixed by r216138: Author: Jonathan Roelofs <[email protected]> Date: Wed Aug 20 23:38:50 2014 +0000 Lower thumbv4t & thumbv5 lo->lo copies through a push-pop sequence On pre-v6 hardware, 'MOV lo, lo' gives undefined results, so such copies need to be avoided. This patch trades simplicity for implementation time at the expense of performance... As they say: correctness first, then performance. See http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-August/075998.html for a few ideas on how to make this better. AsmParser also doesn't permit MOV lo, lo (or CPY, as it used to be known), so you can't use it in embedded asm, but MC does permit it, so using clang to assemble a .s file with --target=thumbv4t-none-eabi gives no error but should. That's less of a problem though. -- You are receiving this mail because: You are on the CC list for the bug.
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