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From: Paolo Bonzini <pbonzini@redhat.com>
To: Richard Henderson <richard.henderson@linaro.org>, qemu-devel@nongnu.org
Subject: Re: [PATCH 02/20] tcg/optimize: Add one's mask to TempOptInfo
Date: Tue, 6 May 2025 13:05:11 +0200	[thread overview]
Message-ID: <b94f0dcf-6f55-45e9-866c-ad2e59ce85a7@redhat.com> (raw)
In-Reply-To: <20250505202751.3510517-3-richard.henderson@linaro.org>

On 5/5/25 22:27, Richard Henderson wrote:
> +    /* Bits that are known 1 and bits that are known 0 must not overlap. */
> +    tcg_debug_assert((o_mask & ~z_mask) == 0);
> +
> +    /* All bits that are not known zero are known one is a constant. */
> +    if (z_mask == o_mask) {
> +        return tcg_opt_gen_movi(ctx, op, op->args[0], o_mask);
> +    }
> +    /* All bits known zero is zero. */
>       if (z_mask == 0) {
>           return tcg_opt_gen_movi(ctx, op, op->args[0], 0);
>       }
Just a nit, but this second check is now redundant.  z_mask == 0 implies 
that o_mask == 0 (otherwise o_mask & z_mask is not zero); therefore the 
"if (z_mask == o_mask)" must have returned from fold_masks_zos().

Really nice!

Paolo



  reply	other threads:[~2025-05-06 11:06 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-05 20:27 [PATCH 00/20] tcg/optimize: Track and use known 1's Richard Henderson
2025-05-05 20:27 ` [PATCH 01/20] tcg/optimize: Introduce arg_const_val Richard Henderson
2025-06-24 22:21   ` Pierrick Bouvier
2025-05-05 20:27 ` [PATCH 02/20] tcg/optimize: Add one's mask to TempOptInfo Richard Henderson
2025-05-06 11:05   ` Paolo Bonzini [this message]
2025-05-06 14:12     ` Richard Henderson
2025-06-24 22:38   ` Pierrick Bouvier
2025-05-05 20:27 ` [PATCH 03/20] tcg/optimize: Build and use o_bits in fold_and Richard Henderson
2025-06-24 22:42   ` Pierrick Bouvier
2025-05-05 20:27 ` [PATCH 04/20] tcg/optimize: Build and use o_bits in fold_andc Richard Henderson
2025-06-24 23:20   ` Pierrick Bouvier
2025-05-05 20:27 ` [PATCH 05/20] tcg/optimize: Build and use z_bits and o_bits in fold_eqv Richard Henderson
2025-06-24 23:55   ` Pierrick Bouvier
2025-05-05 20:27 ` [PATCH 06/20] tcg/optimize: Build and use z_bits and o_bits in fold_nand Richard Henderson
2025-05-05 20:27 ` [PATCH 07/20] tcg/optimize: Build and use z_bits and o_bits in fold_nor Richard Henderson
2025-05-05 20:27 ` [PATCH 08/20] tcg/optimize: Build and use z_bits and o_bits in fold_not Richard Henderson
2025-05-05 20:27 ` [PATCH 09/20] tcg/optimize: Build and use one and affected bits in fold_or Richard Henderson
2025-05-05 20:27 ` [PATCH 10/20] tcg/optimize: Build and use zero, one and affected bits in fold_orc Richard Henderson
2025-05-05 20:27 ` [PATCH 11/20] tcg/optimize: Build and use o_bits in fold_xor Richard Henderson
2025-05-05 20:27 ` [PATCH 12/20] tcg/optimize: Build and use o_bits in fold_bswap Richard Henderson
2025-05-05 20:27 ` [PATCH 13/20] tcg/optimize: Build and use o_bits in fold_deposit Richard Henderson
2025-05-05 20:27 ` [PATCH 14/20] tcg/optimize: Build and use o_bits in fold_extract Richard Henderson
2025-05-05 20:27 ` [PATCH 15/20] tcg/optimize: Build and use z_bits and o_bits in fold_extract2 Richard Henderson
2025-05-06 11:12   ` Paolo Bonzini
2025-05-06 14:15     ` Richard Henderson
2025-05-05 20:27 ` [PATCH 16/20] tcg/optimize: Build and use o_bits in fold_exts Richard Henderson
2025-05-05 20:27 ` [PATCH 17/20] tcg/optimize: Build and use o_bits in fold_extu Richard Henderson
2025-05-05 20:27 ` [PATCH 18/20] tcg/optimize: Build and use o_bits in fold_movcond Richard Henderson
2025-05-05 20:27 ` [PATCH 19/20] tcg/optimize: Build and use o_bits in fold_sextract Richard Henderson
2025-05-05 20:27 ` [PATCH 20/20] tcg/optimize: Build and use o_bits in fold_shift Richard Henderson

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