Re: optimization/7909: ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above

Re: optimization/7909: ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above

[rth]

Synopsis: ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above

State-Changed-From-To: open->closed
State-Changed-By: rth
State-Changed-When: Sun Oct  6 19:46:06 2002
State-Changed-Why:
    Duplicate of 7908

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7909

Re: optimization/7909: ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above

[tprinceusa]

The following reply was made to PR optimization/7909; it has been noted by GNATS.

From: "tprinceusa" <tprinceusa@netzero.net>
To: <ben@zeus.com>,
	<gcc-gnats@gcc.gnu.org>
Cc:  
Subject: Re: optimization/7909: ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above
Date: Sat, 14 Sep 2002 22:27:18 -0700

 ----- Original Message -----
 From: <ben@zeus.com>
 To: <gcc-gnats@gcc.gnu.org>
 Sent: Friday, September 13, 2002 6:38 AM
 Subject: optimization/7909: ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above
 
 
 >
 > >Number:         7909
 > >Category:       optimization
 > >Synopsis:       ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above
 > >Confidential:   no
 > >Severity:       non-critical
 > >Priority:       medium
 > >Responsible:    unassigned
 > >State:          open
 > >Class:          sw-bug
 > >Submitter-Id:   net
 > >Arrival-Date:   Fri Sep 13 06:46:02 PDT 2002
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Ben
 > >Release:        3.2
 > >Organization:
 > >Environment:
 > Compiling native code for a ia64 box
 > >Description:
 > The code sample is a fairly ugly routine to convert pointers
 > into a hex string. The code compiles fine with all levels of
 > optimisation. However, with -O2 and above, gcc reports the
 > following warning messages:
 >
 > /tmp/cc2HCufe.s: Assembler messages:
 > /tmp/cc2HCufe.s:133: Warning: Use of 'mov' may violate WAW dependency 'GR%, % in 1 - 127' (impliedf), specific resource number is
 14
 I see such messages reported consistently in gcc testsuite, for fp-cmp5.  In some cases, including this, the compiled code runs OK.
 It is possible to provoke many more such problems, e.g. by use of -frename-registers -O2, some of which do involve broken code
 generation.  Do others simply suppress these warnings?
 
 
 
 
 
 
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optimization/7909: ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above

[ben]

>Number:         7909
>Category:       optimization
>Synopsis:       ia64 warning 'Use of 'mov' may violate WAW dependency' on -O2 and above
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Sep 13 06:46:02 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Ben
>Release:        3.2
>Organization:
>Environment:
Compiling native code for a ia64 box
>Description:
The code sample is a fairly ugly routine to convert pointers
into a hex string. The code compiles fine with all levels of
optimisation. However, with -O2 and above, gcc reports the
following warning messages:

/tmp/cc2HCufe.s: Assembler messages:
/tmp/cc2HCufe.s:133: Warning: Use of 'mov' may violate WAW dependency 'GR%, % in 1 - 127' (impliedf), specific resource number is 14
/tmp/cc2HCufe.s:133: Warning: Only the first path encountering the conflict is reported
>How-To-Repeat:
Compile the code with -O2 or above. No other compile flags required.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
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