Re: [PATCH] sra: Disqualify bases of operands of asm gotos

[Richard Biener <rguenther@suse.de>]

On Wed, 17 Jan 2024, Martin Jambor wrote:

> Hi,
> 
> PR 110422 shows that SRA can ICE assuming there is a single edge
> outgoing from a block terminated with an asm goto.  We need that for
> BB-terminating statements so that any adjustments they make to the
> aggregates can be copied over to their replacements.  Because we can't
> have that after ASM gotos, we need to punt.
> 
> Bootstrapped and tested on x86_64-linux, OK for master?  It will need
> some tweaking for release branches, is it in principle OK for them too
> (after testing)?

OK.

> Thanks,
> 
> Martin
> 
> 
> gcc/ChangeLog:
> 
> 2024-01-17  Martin Jambor  <mjambor@suse.cz>
> 
> 	PR tree-optimization/110422
> 	* tree-sra.cc (scan_function): Disqualify bases of operands of asm
> 	gotos.
> 
> gcc/testsuite/ChangeLog:
> 
> 2024-01-17  Martin Jambor  <mjambor@suse.cz>
> 
> 	PR tree-optimization/110422
> 	* gcc.dg/torture/pr110422.c: New test.
> ---
>  gcc/testsuite/gcc.dg/torture/pr110422.c | 10 +++++++++
>  gcc/tree-sra.cc                         | 29 ++++++++++++++++++++-----
>  2 files changed, 33 insertions(+), 6 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/torture/pr110422.c
> 
> diff --git a/gcc/testsuite/gcc.dg/torture/pr110422.c b/gcc/testsuite/gcc.dg/torture/pr110422.c
> new file mode 100644
> index 00000000000..2e171a7a19e
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/torture/pr110422.c
> @@ -0,0 +1,10 @@
> +/* { dg-do compile } */
> +
> +struct T { int x; };
> +int foo(void) {
> +  struct T v;
> +  asm goto("" : "+r"(v.x) : : : lab);
> +  return 0;
> +lab:
> +  return -5;
> +}
> diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
> index 6a1141b7377..f8e71ec48b9 100644
> --- a/gcc/tree-sra.cc
> +++ b/gcc/tree-sra.cc
> @@ -1559,15 +1559,32 @@ scan_function (void)
>  	    case GIMPLE_ASM:
>  	      {
>  		gasm *asm_stmt = as_a <gasm *> (stmt);
> -		for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
> +		if (stmt_ends_bb_p (asm_stmt)
> +		    && !single_succ_p (gimple_bb (asm_stmt)))
>  		  {
> -		    t = TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
> -		    ret |= build_access_from_expr (t, asm_stmt, false);
> +		    for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
> +		      {
> +			t = TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
> +			disqualify_base_of_expr (t, "OP of asm goto.");
> +		      }
> +		    for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
> +		      {
> +			t = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
> +			disqualify_base_of_expr (t, "OP of asm goto.");
> +		      }
>  		  }
> -		for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
> +		else
>  		  {
> -		    t = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
> -		    ret |= build_access_from_expr (t, asm_stmt, true);
> +		    for (i = 0; i < gimple_asm_ninputs (asm_stmt); i++)
> +		      {
> +			t = TREE_VALUE (gimple_asm_input_op (asm_stmt, i));
> +			ret |= build_access_from_expr (t, asm_stmt, false);
> +		      }
> +		    for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
> +		      {
> +			t = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
> +			ret |= build_access_from_expr (t, asm_stmt, true);
> +		      }
>  		  }
>  	      }
>  	      break;
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)