simplify-rtx: Fix up simplify_logical_relational_operation for vector IOR [PR101008]

Hi!

simplify_relational_operation callees typically return just const0_rtx
or const_true_rtx and then simplify_relational_operation attempts to fix
that up if the comparison result has vector mode, or floating mode,
or punt if it has scalar mode and vector mode operands (it doesn't know how
exactly to deal with the scalar masks).
But, simplify_logical_relational_operation has a special case, where
it attempts to fold (x < y) | (x >= y) etc. and if it determines it is
always true, it just returns const_true_rtx, without doing the dances that
simplify_relational_operation does.
That results in an ICE on the following testcase, where such folding happens
during expansion (of debug stmts into DEBUG_INSNs) and we ICE because
all of sudden a VOIDmode rtx appears where it expects a vector (V4SImode)
rtx.

The following patch fixes that by moving the adjustement into a separate
helper routine and using it from both simplify_relational_operation and
simplify_logical_relational_operation.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2021-06-11  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/101008
	* simplify-rtx.c (relational_result): New function.
	(simplify_logical_relational_operation,
	simplify_relational_operation): Use it.

	* gcc.dg/pr101008.c: New test.


	Jakub

On Fri, 11 Jun 2021, Jakub Jelinek wrote:

> Hi!
> 
> simplify_relational_operation callees typically return just const0_rtx
> or const_true_rtx and then simplify_relational_operation attempts to fix
> that up if the comparison result has vector mode, or floating mode,
> or punt if it has scalar mode and vector mode operands (it doesn't know how
> exactly to deal with the scalar masks).
> But, simplify_logical_relational_operation has a special case, where
> it attempts to fold (x < y) | (x >= y) etc. and if it determines it is
> always true, it just returns const_true_rtx, without doing the dances that
> simplify_relational_operation does.
> That results in an ICE on the following testcase, where such folding happens
> during expansion (of debug stmts into DEBUG_INSNs) and we ICE because
> all of sudden a VOIDmode rtx appears where it expects a vector (V4SImode)
> rtx.
> 
> The following patch fixes that by moving the adjustement into a separate
> helper routine and using it from both simplify_relational_operation and
> simplify_logical_relational_operation.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK.

Thanks,
Richard.

> 2021-06-11  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR rtl-optimization/101008
> 	* simplify-rtx.c (relational_result): New function.
> 	(simplify_logical_relational_operation,
> 	simplify_relational_operation): Use it.
> 
> 	* gcc.dg/pr101008.c: New test.
> 
> --- gcc/simplify-rtx.c.jj	2021-05-04 21:02:24.000000000 +0200
> +++ gcc/simplify-rtx.c	2021-06-10 13:56:48.946628822 +0200
> @@ -2294,6 +2294,53 @@ comparison_code_valid_for_mode (enum rtx
>  	gcc_unreachable ();
>      }
>  }
> +
> +/* Canonicalize RES, a scalar const0_rtx/const_true_rtx to the right
> +   false/true value of comparison with MODE where comparison operands
> +   have CMP_MODE.  */
> +
> +static rtx
> +relational_result (machine_mode mode, machine_mode cmp_mode, rtx res)
> +{
> +  if (SCALAR_FLOAT_MODE_P (mode))
> +    {
> +      if (res == const0_rtx)
> +        return CONST0_RTX (mode);
> +#ifdef FLOAT_STORE_FLAG_VALUE
> +      REAL_VALUE_TYPE val = FLOAT_STORE_FLAG_VALUE (mode);
> +      return const_double_from_real_value (val, mode);
> +#else
> +      return NULL_RTX;
> +#endif
> +    }
> +  if (VECTOR_MODE_P (mode))
> +    {
> +      if (res == const0_rtx)
> +	return CONST0_RTX (mode);
> +#ifdef VECTOR_STORE_FLAG_VALUE
> +      rtx val = VECTOR_STORE_FLAG_VALUE (mode);
> +      if (val == NULL_RTX)
> +	return NULL_RTX;
> +      if (val == const1_rtx)
> +	return CONST1_RTX (mode);
> +
> +      return gen_const_vec_duplicate (mode, val);
> +#else
> +      return NULL_RTX;
> +#endif
> +    }
> +  /* For vector comparison with scalar int result, it is unknown
> +     if the target means here a comparison into an integral bitmask,
> +     or comparison where all comparisons true mean const_true_rtx
> +     whole result, or where any comparisons true mean const_true_rtx
> +     whole result.  For const0_rtx all the cases are the same.  */
> +  if (VECTOR_MODE_P (cmp_mode)
> +      && SCALAR_INT_MODE_P (mode)
> +      && res == const_true_rtx)
> +    return NULL_RTX;
> +
> +  return res;
> +}
>  				       
>  /* Simplify a logical operation CODE with result mode MODE, operating on OP0
>     and OP1, which should be both relational operations.  Return 0 if no such
> @@ -2329,7 +2376,7 @@ simplify_context::simplify_logical_relat
>    int mask = mask0 | mask1;
>  
>    if (mask == 15)
> -    return const_true_rtx;
> +    return relational_result (mode, GET_MODE (op0), const_true_rtx);
>  
>    code = mask_to_comparison (mask);
>  
> @@ -5315,51 +5362,7 @@ simplify_context::simplify_relational_op
>  
>    tem = simplify_const_relational_operation (code, cmp_mode, op0, op1);
>    if (tem)
> -    {
> -      if (SCALAR_FLOAT_MODE_P (mode))
> -	{
> -          if (tem == const0_rtx)
> -            return CONST0_RTX (mode);
> -#ifdef FLOAT_STORE_FLAG_VALUE
> -	  {
> -	    REAL_VALUE_TYPE val;
> -	    val = FLOAT_STORE_FLAG_VALUE (mode);
> -	    return const_double_from_real_value (val, mode);
> -	  }
> -#else
> -	  return NULL_RTX;
> -#endif
> -	}
> -      if (VECTOR_MODE_P (mode))
> -	{
> -	  if (tem == const0_rtx)
> -	    return CONST0_RTX (mode);
> -#ifdef VECTOR_STORE_FLAG_VALUE
> -	  {
> -	    rtx val = VECTOR_STORE_FLAG_VALUE (mode);
> -	    if (val == NULL_RTX)
> -	      return NULL_RTX;
> -	    if (val == const1_rtx)
> -	      return CONST1_RTX (mode);
> -
> -	    return gen_const_vec_duplicate (mode, val);
> -	  }
> -#else
> -	  return NULL_RTX;
> -#endif
> -	}
> -      /* For vector comparison with scalar int result, it is unknown
> -	 if the target means here a comparison into an integral bitmask,
> -	 or comparison where all comparisons true mean const_true_rtx
> -	 whole result, or where any comparisons true mean const_true_rtx
> -	 whole result.  For const0_rtx all the cases are the same.  */
> -      if (VECTOR_MODE_P (cmp_mode)
> -	  && SCALAR_INT_MODE_P (mode)
> -	  && tem == const_true_rtx)
> -	return NULL_RTX;
> -
> -      return tem;
> -    }
> +    return relational_result (mode, cmp_mode, tem);
>  
>    /* For the following tests, ensure const0_rtx is op1.  */
>    if (swap_commutative_operands_p (op0, op1)
> --- gcc/testsuite/gcc.dg/pr101008.c.jj	2021-06-10 14:20:02.230559294 +0200
> +++ gcc/testsuite/gcc.dg/pr101008.c	2021-06-10 14:19:36.518911260 +0200
> @@ -0,0 +1,18 @@
> +/* PR rtl-optimization/101008 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -g" } */
> +
> +typedef unsigned __attribute__((__vector_size__(32))) U;
> +typedef unsigned __attribute__((__vector_size__(16))) V;
> +
> +int c, r;
> +
> +V v;
> +
> +void
> +foo(void)
> +{
> +  U u = __builtin_shufflevector (v, (V)(v != c) | (V)(c == v),
> +				 4, 3, 5, 5, 1, 2, 3, 0);
> +  r = ((union { U a; int b; }) u).b;
> +}
> 
> 	Jakub
> 
>