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From: ehrhardt@mathematik.uni-ulm.de To: Joerg-Cyril.Hoehle@T-Systems.com, bruno@clisp.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org, sds@gnu.org Subject: Re: optimization/10684: register variable update disappears when using -O Date: Thu, 08 May 2003 18:52:00 -0000 [thread overview] Message-ID: <20030508185226.1292.qmail@sources.redhat.com> (raw) Synopsis: register variable update disappears when using -O State-Changed-From-To: open->analyzed State-Changed-By: cae State-Changed-When: Thu May 8 18:52:25 2003 State-Changed-Why: Confirmed, still present in 3.4-cvs. This is a reduced testcase: register int STACK __asm__("%ebx"); static void (*p) (); void f () { STACK += 1; p (); STACK -= 1; } Looking at the assembly shows that STACK += 1 ist lost if compiled with -O. The problem seems to be that life analysis adds a REG_DEAD note to the call to (*p) which makes STACK += 1 a dead store. regards Christian http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10684
next reply other threads:[~2003-05-08 18:52 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2003-05-08 18:52 ehrhardt [this message] 2003-05-08 23:46 Jim Wilson
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