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[PATCH, i386]: Fix PR81763, Issues with BMI on 32bit x86 apps on GCC 7.1+

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>
Cc: Jakub Jelinek <jakub at redhat dot com>
Date: Fri, 26 Jan 2018 16:45:21 +0100
Subject: [PATCH, i386]: Fix PR81763, Issues with BMI on 32bit x86 apps on GCC 7.1+
Authentication-results: sourceware.org; auth=none

Hello!

It turned out that *andndi3_doubleword pattern needs earlyclobber on
the output operand of its (=r,r,rm) alternative to prevent partial
regs of the first split instruction from clobbering input operands of
the second insn.The patch also adds a couple of alternatives with
matching input and output operands that are guaranteed to not clobber
the other input operand in a sequence of split insns of a
three-operand non-destructive insn.

2018-01-26  Uros Bizjak  <ubizjak@gmail.com>

    PR target/81763
    * config/i386/i386.md (*andndi3_doubleword): Add earlyclobber
    to (=&r,r,rm) alternative. Add (=r,0,rm) and (=r,r,0) alternatives.

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

Committed to mainline, will be bacported to gcc-7 branch early next week.

Uros.

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