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From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Subject: [PATCH v2 0/5] tcg/i386: Improve vector shifts
Date: Sat, 30 Aug 2025 13:39:21 +1000	[thread overview]
Message-ID: <20250830033926.372955-1-richard.henderson@linaro.org> (raw)

x86 doesn't directly support 8-bit vector shifts, so we have
some 2 to 5 insn expansions.  With VGF2P8AFFINEQB, we can do
it in 1 insn, plus a (possibly shared) constant load.

Changes for v2:
  - Use PCMPGT for arithmetic right-shift of bits-1 (paolo).
  - Tidy an instance of non-canonical operand ordering.

r~

Richard Henderson (5):
  cpuinfo/i386: Detect GFNI as an AVX extension
  tcg/i386: Expand sari of bits-1 as pcmpgt
  tcg/i386: Use canonical operand ordering in expand_vec_sari
  tcg/i386: Add INDEX_op_x86_vgf2p8affineqb_vec
  tcg/i386: Use vgf2p8affineqb for MO_8 vector shifts

 host/include/i386/host/cpuinfo.h |  1 +
 include/qemu/cpuid.h             |  3 ++
 util/cpuinfo-i386.c              |  1 +
 tcg/i386/tcg-target-opc.h.inc    |  1 +
 tcg/i386/tcg-target.c.inc        | 91 +++++++++++++++++++++++++++++---
 5 files changed, 91 insertions(+), 6 deletions(-)

-- 
2.43.0



             reply	other threads:[~2025-08-30 16:20 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-30  3:39 Richard Henderson [this message]
2025-08-30  3:39 ` [PATCH v2 1/5] cpuinfo/i386: Detect GFNI as an AVX extension Richard Henderson
2025-08-30  3:39 ` [PATCH v2 2/5] tcg/i386: Expand sari of bits-1 as pcmpgt Richard Henderson
2025-08-30  3:39 ` [PATCH v2 3/5] tcg/i386: Use canonical operand ordering in expand_vec_sari Richard Henderson
2025-09-01  6:44   ` Philippe Mathieu-Daudé
2025-09-02 13:28     ` Richard Henderson
2025-08-30  3:39 ` [PATCH v2 4/5] tcg/i386: Add INDEX_op_x86_vgf2p8affineqb_vec Richard Henderson
2025-08-30  3:39 ` [PATCH v2 5/5] tcg/i386: Use vgf2p8affineqb for MO_8 vector shifts Richard Henderson

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