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From: "kirill.yukhin at intel dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/49547] New: LZCNT should be enabled only if ABM or LZCNT bits are set
Date: Mon, 27 Jun 2011 16:51:00 -0000	[thread overview]
Message-ID: <bug-49547-4@http.gcc.gnu.org/bugzilla/> (raw)

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49547

           Summary: LZCNT should be enabled only if ABM or LZCNT bits are
                    set
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: kirill.yukhin@intel.com


Hi,
according to freshest Specs, we need to enable LZCNT only when ABM or LZCNT
bits of CPUID (leaf 8000_0001h) is set.
However config/i386/i386.md has:

(define_insn "clz<mode>2_abm"
  [(set (match_operand:SWI248 0 "register_operand" "=r")
        (clz:SWI248 (match_operand:SWI248 1 "nonimmediate_operand" "rm")))
   (clobber (reg:CC FLAGS_REG))]
  "TARGET_ABM || TARGET_BMI"
  "lzcnt{<imodesuffix>}\t{%1, %0|%0, %1}"
  [(set_attr "prefix_rep" "1")
   (set_attr "type" "bitmanip")
   (set_attr "mode" "<MODE>")])

There is no connection to BMI anymore.


             reply	other threads:[~2011-06-27 16:51 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-27 16:51 kirill.yukhin at intel dot com [this message]
2011-06-27 16:53 ` [Bug target/49547] " hjl.tools at gmail dot com
2011-07-27  5:04 ` kirill.yukhin at intel dot com
2011-07-27 17:59 ` kirill.yukhin at intel dot com
2011-07-27 18:03 ` hjl.tools at gmail dot com
2011-07-27 18:07 ` kirill.yukhin at intel dot com
2011-08-01 13:48 ` hjl at gcc dot gnu.org
2011-08-01 13:57 ` hjl.tools at gmail dot com

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