search for: __writeeflags

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 t...

...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 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 mat...

...tion. 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 register for >> __readeflags and pushf and pop to register for __writeeflags. >> These instructions are not connected explicitly so I can't use patterns >&gt...

On Tue, Dec 17, 2013 at 01:05:10PM -0800, David Majnemer wrote: > This intrinsic seems very ill-defined, apparently it can be freely > reordered and does _not_ act like a compiler barrier. [1] > Other than source compatibility, why would one want this intrinsic? What > semantics is it supposed to give? Even more, why can't it just be defined as inline function in some header?

On 18 Dec 2013, at 11:03, Alexey Volkov <avolkov.intel at gmail.com> wrote: > These intrinsics are introduced for compatibility purposes. > Besides MSVC GCC also supports it in its main trunk; ICC supports it on Windows and is going to support in the next version on Linux. There have been two questions, neither of which is really answered. The questions are: - Why does this need

These intrinsics are introduced for compatibility purposes. Besides MSVC GCC also supports it in its main trunk; ICC supports it on Windows and is going to support in the next version on Linux. 2013/12/18 Joerg Sonnenberger <joerg at britannica.bec.de> > On Tue, Dec 17, 2013 at 01:05:10PM -0800, David Majnemer wrote: > > This intrinsic seems very ill-defined, apparently it can be