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[PATCH, i386]: Fix PR46091, missed optimization: x86 bt/btc/bts instructions

From: Uros Bizjak <ubizjak at gmail dot com>
To: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
Date: Mon, 14 Aug 2017 18:56:06 +0200
Subject: [PATCH, i386]: Fix PR46091, missed optimization: x86 bt/btc/bts instructions
Authentication-results: sourceware.org; auth=none

Hello!

Attached patch implements generation of btr, bts and btc instructions.
These insns are generated for operations with registers and exact log2
immediates, where bitpos <= 63 and >= 31. Immediates with bits >= 31
are out of range for x86 andq/orq/xorq instructions, so we save a
movabsq constant load.

2017-08-14  Uros Bizjak  <ubizjak@gmail.com>

    PR target/46091
    * config/i386/i386.md (*anddi_1_btr): New insn_and_split pattern.
    (*iordi_1_bts): Ditto.
    (*xordi_1_btc): Ditto.

testsuite/ChangeLog:

2017-08-14  Uros Bizjak  <ubizjak@gmail.com>

    PR target/46091
    * gcc.target/i386/pr46091-1.c: New test.
    * gcc.target/i386/pr46091-2.c: Ditto.
    * gcc.target/i386/pr46091-3.c: Ditto.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Committed to mainline.

Uros.

Attachment: p.diff.txt
Description: Text document

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