[PATCH 4/4] x86: Add 'V' register operand modifier

[Jan Hubicka]

> Add 'V', a special modifier which prints the name of the full integer
> register without '%'.  For
> 
> extern void (*func_p) (void);
> 
> void
> foo (void)
> {
>   asm ("call __x86_indirect_thunk_%V0" : : "a" (func_p));
> }
> 
> it generates:
> 
> foo:
> 	movq	func_p(%rip), %rax
> 	call	__x86_indirect_thunk_rax
> 	ret
> 
> gcc/
> 
> 	* config/i386/i386.c (print_reg): Print the name of the full
> 	integer register without '%'.
> 	(ix86_print_operand): Handle 'V'.
> 	 * doc/extend.texi: Document 'V' modifier.

Seems reasonable. Purpose of this is to make posible to call thunks
from asm statements, right?

Honza
> 
> gcc/testsuite/
> 
> 	* gcc.target/i386/indirect-thunk-register-4.c: New test.
> ---
>  gcc/config/i386/i386.c                                    | 13 ++++++++++++-
>  gcc/doc/extend.texi                                       |  3 +++
>  gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c | 13 +++++++++++++
>  3 files changed, 28 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c
> 
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 9ffcb69d6d7..e69135d7191 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -17617,6 +17617,7 @@ put_condition_code (enum rtx_code code, machine_mode mode, bool reverse,
>     If CODE is 'h', pretend the reg is the 'high' byte register.
>     If CODE is 'y', print "st(0)" instead of "st", if the reg is stack op.
>     If CODE is 'd', duplicate the operand for AVX instruction.
> +   If CODE is 'V', print naked full integer register name without %.
>   */
>  
>  void
> @@ -17627,7 +17628,7 @@ print_reg (rtx x, int code, FILE *file)
>    unsigned int regno;
>    bool duplicated;
>  
> -  if (ASSEMBLER_DIALECT == ASM_ATT)
> +  if (ASSEMBLER_DIALECT == ASM_ATT && code != 'V')
>      putc ('%', file);
>  
>    if (x == pc_rtx)
> @@ -17679,6 +17680,14 @@ print_reg (rtx x, int code, FILE *file)
>        return;
>      }
>  
> +  if (code == 'V')
> +    {
> +      if (GENERAL_REGNO_P (regno))
> +	msize = GET_MODE_SIZE (word_mode);
> +      else
> +	error ("'V' modifier on non-integer register");
> +    }
> +
>    duplicated = code == 'd' && TARGET_AVX;
>  
>    switch (msize)
> @@ -17798,6 +17807,7 @@ print_reg (rtx x, int code, FILE *file)
>     & -- print some in-use local-dynamic symbol name.
>     H -- print a memory address offset by 8; used for sse high-parts
>     Y -- print condition for XOP pcom* instruction.
> +   V -- print naked full integer register name without %.
>     + -- print a branch hint as 'cs' or 'ds' prefix
>     ; -- print a semicolon (after prefixes due to bug in older gas).
>     ~ -- print "i" if TARGET_AVX2, "f" otherwise.
> @@ -18021,6 +18031,7 @@ ix86_print_operand (FILE *file, rtx x, int code)
>  	case 'X':
>  	case 'P':
>  	case 'p':
> +	case 'V':
>  	  break;
>  
>  	case 's':
> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
> index f120b2a1429..dce808f1eab 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -9292,6 +9292,9 @@ The table below shows the list of supported modifiers and their effects.
>  @tab @code{2}
>  @end multitable
>  
> +@code{V} is a special modifier which prints the name of the full integer
> +register without @code{%}.
> +
>  @anchor{x86floatingpointasmoperands}
>  @subsubsection x86 Floating-Point @code{asm} Operands
>  
> diff --git a/gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c b/gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c
> new file mode 100644
> index 00000000000..f0cd9b75be8
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/indirect-thunk-register-4.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mindirect-branch=keep -fno-pic" } */
> +
> +extern void (*func_p) (void);
> +
> +void
> +foo (void)
> +{
> +  asm("call __x86_indirect_thunk_%V0" : : "a" (func_p));
> +}
> +
> +/* { dg-final { scan-assembler "call\[ \t\]*__x86_indirect_thunk_eax" { target ia32 } } } */
> +/* { dg-final { scan-assembler "call\[ \t\]*__x86_indirect_thunk_rax" { target { ! ia32 } } } } */
> -- 
> 2.14.3