search for: id1164

...AC? Even DF is typically scratch, and could be used for an -Oz memmove lowering for example. I don't think LLVM will ever really support capturing ALU flags from previous ops without "using" the operation. LLVM does have overflow intrinsics though: http://llvm.org/docs/LangRef.html#id1164 On Tue, Dec 17, 2013 at 1:02 AM, Alexey Volkov <avolkov.intel at gmail.com>wrote: > Hello all, > > I am trying to implement intrinsics __readeflags and __writeeflags reading > and writing EFLAGS register on x86. > These intrinsics expand to two instructions popf and push to...

Hello all, I am trying to implement intrinsics __readeflags and __writeeflags reading and writing EFLAGS register on x86. These intrinsics expand to two instructions popf and push to register for __readeflags and pushf and pop to register for __writeeflags. These instructions are not connected explicitly so I can't use patterns in .td file to match intrinsics. I tried to implement custom

...atch, and could be used for an -Oz > memmove lowering for example. > > I don't think LLVM will ever really support capturing ALU flags from > previous ops without "using" the operation. LLVM does have overflow > intrinsics though: > http://llvm.org/docs/LangRef.html#id1164 > > > On Tue, Dec 17, 2013 at 1:02 AM, Alexey Volkov <avolkov.intel at gmail.com>wrote: > >> Hello all, >> >> I am trying to implement intrinsics __readeflags and __writeeflags >> reading and writing EFLAGS register on x86. >> These intrinsics expand...