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From: "mikpe at it dot uu.se" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/55171] incorrect virtual thunk on mingw Date: Sun, 11 Nov 2012 14:30:00 -0000 [thread overview] Message-ID: <bug-55171-4-EOzk9jSccM@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-55171-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55171 Mikael Pettersson <mikpe at it dot uu.se> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |mikpe at it dot uu.se --- Comment #5 from Mikael Pettersson <mikpe at it dot uu.se> 2012-11-11 14:30:14 UTC --- It's caused by "[patch i386]: Set for method-functions default calling-convention to thiscall for 32-bit msabi" in r171890: http://gcc.gnu.org/ml/gcc-patches/2011-04/msg00066.html http://gcc.gnu.org/ml/gcc-cvs/2011-04/msg00082.html With x86_64-w64-mingw32-g++ -m32 -O2 there are numerous code generation differences in r171890 for this test case (as expected with the changed calling convention), but looking only at the virtual thunk we see: --- pr55171.s-r171889 2012-11-11 14:51:38.000000000 +0100 +++ pr55171.s-r171890 2012-11-11 15:00:58.000000000 +0100 ... __ZTv0_n16_NK7Derived3fooEv: - movl 8(%esp), %eax - movl (%eax), %ecx - addl -16(%ecx), %eax - movl %eax, 8(%esp) + movl 4(%esp), %eax + movl (%eax), %eax + addl -16(%eax), %eax + movl %eax, 4(%esp) jmp LTHUNK2 ... The two code sequences are clearly not equivalent (ignore the stack position of the pointer being adjusted). Running the test case confirms: with g++ @ r171889 it succeeds, but with g++ @ r171890 it gets a runtime failure.
next prev parent reply other threads:[~2012-11-11 14:30 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-11-01 21:11 [Bug c++/55171] New: " mitza at ociweb dot com 2012-11-02 11:13 ` [Bug c++/55171] " paolo.carlini at oracle dot com 2012-11-02 19:51 ` mitza at ociweb dot com 2012-11-02 20:13 ` [Bug target/55171] " paolo.carlini at oracle dot com 2012-11-07 21:10 ` mitza at ociweb dot com 2012-11-11 14:30 ` mikpe at it dot uu.se [this message] 2012-11-23 21:57 ` paolo.carlini at oracle dot com 2012-11-24 12:47 ` [Bug c++/55171] [4.7/4.8 Regression] " ktietz at gcc dot gnu.org 2012-11-24 12:54 ` ktietz at gcc dot gnu.org 2012-11-25 15:55 ` [Bug target/55171] " rguenth at gcc dot gnu.org 2012-11-29 9:19 ` ktietz at gcc dot gnu.org 2012-11-29 9:21 ` ktietz at gcc dot gnu.org 2012-11-29 9:25 ` ktietz at gcc dot gnu.org 2013-05-06 1:10 ` steve.k.chiu at gmail dot com 2013-05-06 22:31 ` i.nixman at gmail dot com
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