On Tue, 19 Nov 2024, Jakub Jelinek wrote:
> Hi!
>
> r15-4601 added match.pd simplification of some TRUNC_DIV_EXPR expressions
> into EXACT_DIV_EXPR, so bitintlower can now encounter even those.
> From bitint lowering POV the fact that the division will be exact
> doesn't matter, we still need to call at runtime the __divmodbitint4
> API and it wouldn't simplify there anything to know it is exact if
> we duplicated that, so the following patch lowers EXACT_DIV_EXPR exactly
> as TRUNC_DIV_EXPR.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
> I think we don't need to backport this unless something introduces
> EXACT_DIV_EXPR on BITINT_TYPEd expressions on the 14 branch as well.
Agreed.
Richard.
> 2024-11-19 Jakub Jelinek <ja...@redhat.com>
>
> PR middle-end/117571
> * gimple-lower-bitint.cc (bitint_large_huge::lower_muldiv_stmt,
> bitint_large_huge::lower_stmt, stmt_needs_operand_addr,
> build_bitint_stmt_ssa_conflicts, gimple_lower_bitint): Handle
> EXACT_DIV_EXPR like TRUNC_DIV_EXPR.
>
> * gcc.dg/bitint-114.c: New test.
>
> --- gcc/gimple-lower-bitint.cc.jj 2024-10-24 18:53:39.263072751 +0200
> +++ gcc/gimple-lower-bitint.cc 2024-11-18 15:37:35.344738882 +0100
> @@ -3597,6 +3597,7 @@ bitint_large_huge::lower_muldiv_stmt (tr
> insert_before (g);
> break;
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> g = gimple_build_call_internal (IFN_DIVMODBITINT, 8,
> lhs, build_int_cst (sitype, prec),
> null_pointer_node,
> @@ -5560,6 +5561,7 @@ bitint_large_huge::lower_stmt (gimple *s
> return;
> case MULT_EXPR:
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> lower_muldiv_stmt (lhs, g);
> goto handled;
> @@ -5694,6 +5696,7 @@ bitint_large_huge::lower_stmt (gimple *s
> return;
> case MULT_EXPR:
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> lower_muldiv_stmt (NULL_TREE, stmt);
> return;
> @@ -5740,6 +5743,7 @@ stmt_needs_operand_addr (gimple *stmt)
> {
> case MULT_EXPR:
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> case FLOAT_EXPR:
> return true;
> @@ -5931,6 +5935,7 @@ build_bitint_stmt_ssa_conflicts (gimple
> {
> case MULT_EXPR:
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> muldiv_p = true;
> default:
> @@ -6174,6 +6179,7 @@ gimple_lower_bitint (void)
> break;
> case MULT_EXPR:
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (s))
> {
> @@ -6455,6 +6461,7 @@ gimple_lower_bitint (void)
> switch (gimple_assign_rhs_code (use_stmt))
> {
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> case FLOAT_EXPR:
> /* For division, modulo and casts to floating
> @@ -6568,6 +6575,7 @@ gimple_lower_bitint (void)
> case RSHIFT_EXPR:
> case MULT_EXPR:
> case TRUNC_DIV_EXPR:
> + case EXACT_DIV_EXPR:
> case TRUNC_MOD_EXPR:
> case FIX_TRUNC_EXPR:
> case REALPART_EXPR:
> --- gcc/testsuite/gcc.dg/bitint-114.c.jj 2024-11-18 15:35:20.374624506
> +0100
> +++ gcc/testsuite/gcc.dg/bitint-114.c 2024-11-18 15:35:55.651131671 +0100
> @@ -0,0 +1,23 @@
> +/* PR middle-end/117571 */
> +/* { dg-do compile { target bitint } } */
> +/* { dg-options "-O2" } */
> +
> +#if __BITINT_MAXWIDTH__ >= 255
> +_BitInt(255) b;
> +
> +_BitInt(255)
> +foo ()
> +{
> + return (b << 10) / 2;
> +}
> +#endif
> +
> +#if __BITINT_MAXWIDTH__ >= 8192
> +_BitInt(8192) c;
> +
> +_BitInt(8192)
> +bar ()
> +{
> + return (c << 1039) /
> 0x20000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000wb;
> +}
> +#endif
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
