From mboxrd@z Thu Jan 1 00:00:00 1970 From: mol@pengutronix.de (Michael Olbrich) Date: Tue, 11 Sep 2012 12:29:05 +0200 Subject: GCC 4.6.x miscompiling arm-linux? In-Reply-To: <20120911113139.3b7b879f@archvile> References: <20120910171654.1d4972b2@archvile> <20120911092753.7b8315d4@archvile> <20120911084853.GT24458@pengutronix.de> <20120911113139.3b7b879f@archvile> Message-ID: <20120911102905.GC14994@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Sep 11, 2012 at 11:31:39AM +0200, David Jander wrote: > On Tue, 11 Sep 2012 10:48:53 +0200 > Sascha Hauer wrote: > > > On Tue, Sep 11, 2012 at 09:27:53AM +0200, David Jander wrote: > > > > > > Hi Matt, > > > > > > > @ Function supports interworking. > > > > @ args = 0, pretend = 0, frame = 0 > > > > @ frame_needed = 0, uses_anonymous_args = 0 > > > > @ link register save eliminated. > > > > cmp r0, #9 > > > > mov r3, #0 > > > > str r3, [r1, #0] > > > > mov r0, #0 > > > > strgt r3, [r1, #4] > > > > bx lr > > > > .size flexcan_chip_start, .-flexcan_chip_start > > > > .ident "GCC: (GNU) 4.3.3" > > > > .section .note.GNU-stack,"",%progbits > > > > > > > > I think this looks correct. Perhaps you could try the angstrom arm5te > > > > toolchain and see if it's a toolchain issue? > > > > > > Yes, this looks a lot better, and is exactly what I get when I compile this > > > code with CodeSourcery GCC-4.4.1 > > > > > > I have tries building gcc-4.6.3 also with OSELAS/PTXdist, and it gives the > > > same (wrong) result as with gcc-4.6.2 > > > > AFAIK our OSELAS/PTXdist Toolchains use Linaro patches, this would > > explain why both have the same result. No, OSELAS Toolchains only uses the Linaro GCC for Cortex-A8/-A9 > It would indeed, if I had just used OSELAS as-is, but I didn't ;-) > I made a copy of > arm-v5te-linux-gnueabi_gcc-4.6.2_glibc-2.14.1_binutils-2.21.1a_kernel-2.6.39-sanitized.ptxconfig > and replaced the version string 4.6.2 with 4.6.3. AFAIK, this way PTXdist will > download pristine gcc-4.6.3 sources and not apply any patches, since there is > no directory named patches/gcc-4.6.3, right? Can I assume that I have an > unpatched version of gcc-4.6.3 then? Correct. This way you'll get gcc-4.6.3 without any patches. > Btw, Here's what I get from it: > > flexcan_chip_start: > @ args = 0, pretend = 0, frame = 0 > @ frame_needed = 0, uses_anonymous_args = 0 > @ link register save eliminated. > mov r3, #0 > cmp r0, #9 > str r3, [r1, #0] > ldrle r3, [r1, #4] > mov r0, #0 > str r3, [r1, #4] > bx lr > .size flexcan_chip_start, .-flexcan_chip_start > .ident "GCC: (OSELAS.Toolchain-2011.11.1) 4.6.3" > .section .note.GNU-stack,"",%progbits How can I reproduce this output? I'd like to test this with different toolchain versions. > Wrong code. > See the version string? It is clearly not an existing OSELAS version. Hmmm, so far it seems all tested gcc-4.6.x versions produce wrong code, correct? Regards, Michael -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |