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 <ja...@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
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
