[PATCH, CHKP, i386] Fix retval generated for instrumented calls returning values on multiple registers

[Jan Hubicka]

> Hi,
> 
> This patch fixes nested PARALLEL in retval for isntrumented calls. Current possible call:
> 
> (call_insn:TI 6 30 17 2 (set (parallel [
>                 (expr_list:REG_DEP_TRUE (parallel:TI [
>                             (expr_list:REG_DEP_TRUE (reg:DF 21 xmm0)
>                                 (const_int 0 [0]))
>                             (expr_list:REG_DEP_TRUE (reg:DF 22 xmm1)
>                                 (const_int 8 [0x8]))
>                         ])
>                     (const_int 0 [0]))
>                 (expr_list:REG_DEP_TRUE (reg:BND64 77 bnd0)
>                     (const_int 0 [0]))
>                 (expr_list:REG_DEP_TRUE (reg:BND64 78 bnd1)
>                     (const_int 0 [0]))
>             ])
>         (call/j (mem:QI (symbol_ref:DI ("test1") [flags 0x41]  <function_decl 0x7f6f50e02ca8 test1.chkp>) [0 test1.chkp S1 A8])
>             (const_int 0 [0]))) complex.c:11 670 {*call_value}
> 
> Such construction causes DF analysis problems.  This patch tranforms it to:
> 
> (call_insn:TI 6 30 17 2 (set (parallel:TI [
>                 (expr_list:REG_DEP_TRUE (reg:DF 21 xmm0)
>                     (const_int 0 [0]))
>                 (expr_list:REG_DEP_TRUE (reg:DF 22 xmm1)
>                     (const_int 8 [0x8]))
>                 (expr_list:REG_DEP_TRUE (reg:BND64 77 bnd0)
>                     (const_int 0 [0]))
>                 (expr_list:REG_DEP_TRUE (reg:BND64 78 bnd1)
>                     (const_int 0 [0]))
>             ])
>         (call/j (mem:QI (symbol_ref:DI ("test1") [flags 0x41]  <function_decl 0x7fb609bf7ca8 test1.chkp>) [0 test1.chkp S1 A8])
>             (const_int 0 [0]))) complex.c:11 670 {*call_value}

Yep, nested parallels should not happen.

> 2015-04-02  Ilya Enkovich  <ilya.enkovich@intel.com>
> 
> 	* config/i386/i386.c (ix86_expand_call): Avoid nested
> 	PARALLEL in returned call value.
> 
> 
> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
> index 744642c..1d821cd 100644
> --- a/gcc/config/i386/i386.c
> +++ b/gcc/config/i386/i386.c
> @@ -25624,8 +25624,19 @@ ix86_expand_call (rtx retval, rtx fnaddr, rtx callarg1,
>  	{
>  	  rtx b0 = gen_rtx_REG (BND64mode, FIRST_BND_REG);
>  	  rtx b1 = gen_rtx_REG (BND64mode, FIRST_BND_REG + 1);
> -	  retval = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (3, retval, b0, b1));
> -	  chkp_put_regs_to_expr_list (retval);
> +	  if (GET_CODE (retval) == PARALLEL)
> +	    {
> +	      b0 = gen_rtx_EXPR_LIST (VOIDmode, b0, const0_rtx);
> +	      b1 = gen_rtx_EXPR_LIST (VOIDmode, b1, const0_rtx);
> +	      rtx par = gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, b0, b1));
> +	      retval = chkp_join_splitted_slot (retval, par);

I do not understand this code. Isn't it just droping the original return value
constructing prallelcontaining only the BND_REGs?

Honza