On Wed, Dec 4, 2013 at 5:59 PM, Kirill Yukhin <kirill.yuk...@gmail.com> wrote:
> MSVC and ICC (currently Windows version, Linux version soon) have > dedicated intrinsics to read/set EFLAGS register ([1], [2]). > > Patch introduces these intrinsics and tests for them. > > Bootstrapped. New tests pass. > Although gate is closed patch is obvious. > So, is it ok for trunk? > > ChangeLog/ > * config/i386/ia32intrin.h (__readeflags): New. > (__writeeflags): Ditto. > > testsuite/ChangeLog/ > * gcc.target/i386/readeflags-1.c: New. > * gcc.target/i386/writeeflags-1.c: Ditto. > > [1] - http://msdn.microsoft.com/en-us/library/aa983406(v=vs.90).aspx > [2] - http://msdn.microsoft.com/en-us/library/aa983392(v=vs.90).aspx > > -- > Thanks, K > > diff --git a/gcc/config/i386/ia32intrin.h b/gcc/config/i386/ia32intrin.h > index b26dc46..c9e68c5 100644 > --- a/gcc/config/i386/ia32intrin.h > +++ b/gcc/config/i386/ia32intrin.h > @@ -238,6 +238,34 @@ __rorq (unsigned long long __X, int __C) > return (__X >> __C) | (__X << (64 - __C)); > } > > +/* Read flags register */ > +extern __inline unsigned long long > +__attribute__((__gnu_inline__, __always_inline__, __artificial__)) > +__readeflags (void) > +{ > + unsigned long long result = 0; > + __asm__ __volatile__ ("pushf\n\t" > + "popq %0\n" > + :"=r"(result) > + : > + : > + ); > + return result; > +} > + > +/* Write flags register */ > +extern __inline void > +__attribute__((__gnu_inline__, __always_inline__, __artificial__)) > +__writeeflags (unsigned long long X) > +{ > + __asm__ __volatile__ ("pushq %0\n\t" > + "popf\n" > + : > + :"r"(X) > + :"flags" > + ); > +} > + Oh, no. We don't want assembly in this century ;) The proper implementation is to introduce a __builtin_readflags/__builtin_writeflags that expand the sequence by calling gen_push and gen_pop functions. You will need new patterns for pushfl and popfl, something like: (define_insn "*pushfl<mode>" [(set (match_operand:DWIH 0 "push_operand" "=<") (match_operand:DWIH 0 "flags_reg_operand"))] "" "pushf{<mode>}" [(set_attr "type" "push") (set_attr "mode" "<MODE>")]) (define_insn "*popfl<mode>1" [(set (match_operand:DWIH 0 "flags_reg_operand") (match_operand:DWIH 1 "pop_operand" ">"))] "" "popf{<imodesuffix>}\t%0" [(set_attr "type" "pop") (set_attr "mode" "<MODE>")]) Uros.
