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* Re: java/8204: gcj -O2 to native reorders certain instructions improperly.
@ 2003-03-24 15:16 bangerth
  0 siblings, 0 replies; 2+ messages in thread
From: bangerth @ 2003-03-24 15:16 UTC (permalink / raw)
  To: gcc-bugs, gcc-prs, java-prs, nobody, rsdio

Synopsis: gcj -O2 to native reorders certain instructions improperly.

State-Changed-From-To: feedback->open
State-Changed-By: bangerth
State-Changed-When: Mon Mar 24 15:16:42 2003
State-Changed-Why:
    Leave this to the Java experts

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8204


^ permalink raw reply	[flat|nested] 2+ messages in thread
* Re: java/8204: gcj -O2 to native reorders certain instructions improperly.
@ 2003-03-22 18:09 bangerth
  0 siblings, 0 replies; 2+ messages in thread
From: bangerth @ 2003-03-22 18:09 UTC (permalink / raw)
  To: gcc-bugs, gcc-prs, java-prs, nobody, rsdio

Synopsis: gcj -O2 to native reorders certain instructions improperly.

State-Changed-From-To: open->feedback
State-Changed-By: bangerth
State-Changed-When: Sat Mar 22 18:09:51 2003
State-Changed-Why:
    In your code, you are modifying i twice in the same line:
      (f(s.charAt(i++)) << 4) | (f(s.charAt(i++))))
    I don't know enough about Java, but in C/C++ this will invoke
    undefined behavior, since the standard doesn't prescribe
    which of the two function calls happen first, and with
    which value of i. Is this different in Java, i.e. does
    the Java standard give guarantees as to the order in which
    the sub-statements are executed?
    
    W.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8204


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