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From: snyder@fnal.gov To: gcc-gnats@gcc.gnu.org Subject: target/6087: 3.1 i86 FP stack pop bug Date: Thu, 28 Mar 2002 16:16:00 -0000 [thread overview] Message-ID: <200203290008.g2T08t305925@karma.fnal.gov> (raw) >Number: 6087 >Category: target >Synopsis: 3.1 i86 FP stack pop bug >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: wrong-code >Submitter-Id: net >Arrival-Date: Thu Mar 28 16:16:02 PST 2002 >Closed-Date: >Last-Modified: >Originator: scott snyder >Release: 3.1 20020326 (prerelease) >Organization: >Environment: System: Linux karma 2.4.9-13 #1 Tue Oct 30 20:11:04 EST 2001 i686 unknown Architecture: i686 host: i686-pc-linux-gnu build: i686-pc-linux-gnu target: i686-pc-linux-gnu configured with: ../egcs/configure --prefix=/usr/local/egcs --enable-threads=posix --enable-long-long --enable-languages=c,c++,f77 >Description: The code below executes incorrectly. Here's what i get: $ g++ -O0 -o x x.cc y.cc $ ./x 25.000000 25.000000 25.000000 25.000000 nan nan What's happening is that the CftRibbon() constructor is not properly popping the result of foobar5() off the FP stack. The stack eventually fills up, and we start getting nan's resulting from FP operations. Here's the generated code for the call to foobar5(): .LEHB0: call _Z7foobar5v .LEHE0: fld %st(0) jmp .L1 Instead of popping the returned value, this duplicates it. >How-To-Repeat: Compile and link together these two sources. -- x.cc ---------------------------------------------------------- struct d0om_Registerable { virtual ~d0om_Registerable () {} }; struct CftRibbon : public d0om_Registerable { CftRibbon (); }; double foobar5 (); CftRibbon::CftRibbon () { foobar5(); } int main () { new CftRibbon; new CftRibbon; new CftRibbon; new CftRibbon; new CftRibbon; new CftRibbon; return 0; } -- y.cc ---------------------------------------------------------- extern "C" int printf(...); double x = 3; double y = 4; double foobar5 () { double z = x*x+y*y; printf ("%lf\n", z); return z; } ------------------------------------------------------------------ >Fix: >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2002-03-29 0:16 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-03-28 16:16 snyder [this message] 2002-03-28 19:41 rth 2002-03-28 22:23 rth
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