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

["tprinceusa" <tprinceusa@netzero.net>]

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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