[Bug inline-asm/37195] different variables get the same overlapping memory address in inline assembly
--- Comment #8 from jdemeyer at cage dot ugent dot be 2010-04-30 07:24 --- On first sight, it looks fixed in gcc 4.6.0 SVN. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug inline-asm/41294] New: =rm constraints give overlapping memory addresses
In some cases in inline asm, an output parameter with no-clobber =rm constraint gets the same address as an input parameter, even when they refer to two different C variables. This seems to happen when the following conditions are satisfied: * The variables involved appear only in inline asm (as the output of one asm statement and the input of a second). * The output constraint is =rm (=m works correctly). * There are too many clobbered variables forcing some of the output parameters into memory. The attached testcase works for i386, x86_64, powerpc and powerpc64. For other targets, change the clobber list to include as much registers as possible. Compile with gcc -O1 -save-temps -c -o bug.o bug.c Tested with gcc -v: Using built-in specs. Target: x86_64-unknown-linux-gnu Configured with: ../gcc/configure CC=/usr/bin/gcc-4.3.4 --prefix=/home/jdemeyer/local --enable-checking=release Thread model: posix gcc version 4.5.0 20090904 (experimental) (GCC) -- Summary: =rm constraints give overlapping memory addresses Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: inline-asm AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jdemeyer at cage dot ugent dot be http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41294
[Bug inline-asm/41294] =rm constraints give overlapping memory addresses
--- Comment #1 from jdemeyer at cage dot ugent dot be 2009-09-07 10:49 --- Created an attachment (id=18528) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18528action=view) Testcase -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41294
[Bug inline-asm/41294] =rm constraints give overlapping memory addresses
--- Comment #3 from jdemeyer at cage dot ugent dot be 2009-09-07 19:30 --- (In reply to comment #2) I think you need to mark both alternatives early-clobber, not only the register one. Thus =rm at least according to the manual. That doesn't seem to change anything. It looks to me like the parser only checks for the presence of at least one , since it even accepts =rm (maybe that's another bug?). On the other hand, using =m as constraint gives an error bug.c:141:2: error: '' constraint used with no register class According to http://gcc.gnu.org/onlinedocs/gcc/Multi_002dAlternative.html, the constraint =rm counts as ONE alternative, since alternatives are seperated by commas. This is one alternative, allowing both a register or memory location. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41294
[Bug c/41263] New: gcc uses all available memory
When compiling the attached program with the command line gcc -v -save-temps -O2 bug.i gcc uses all available memory. gcc -v gives me Using built-in specs. Target: x86_64-unknown-linux-gnu Configured with: ../gcc/configure CC=/usr/bin/gcc-4.3.4 --prefix=/home/jdemeyer/local --enable-checking=release Thread model: posix gcc version 4.5.0 20090904 (experimental) (GCC) -- Summary: gcc uses all available memory Product: gcc Version: 4.5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jdemeyer at cage dot ugent dot be GCC build triplet: x86_64-unknown-linux-gnu GCC host triplet: x86_64-unknown-linux-gnu GCC target triplet: x86_64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41263
[Bug c/41263] gcc uses all available memory
--- Comment #1 from jdemeyer at cage dot ugent dot be 2009-09-04 13:21 --- Created an attachment (id=18493) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18493action=view) Testcase -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41263
[Bug inline-asm/37195] different variables get the same overlapping memory address in inline assembly
--- Comment #5 from jdemeyer at cage dot ugent dot be 2008-09-29 19:22 --- Created an attachment (id=16428) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16428action=view) Unified testcase This testcase exhibits the problem on i386, x86_64, powerpc and powerpc64 using preprocessor macros. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug c/37544] New: Conversion double - unsigned long long - unsigned - double gives wrong results
Consider the following line of the attached test case, where a is double with value 4294967296.0. double b = (unsigned int)((unsigned long long int)a % 4294967296ULL); Then (unsigned long long int)a % 4294967296ULL should be equal to 0ULL, and therefore b should be 0.0. However, when compiled with -O1 -march=pentium4, b gets the wrong value of 4294967296.0 (the same as a). Note that the error only occurs with -march=pentium4. To compile the testcase: gcc -std=c99 -O1 -march=pentium4 convert-bug.i -o convert-bug gcc -v: Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../gcc/configure --enable-checking=release --prefix=/home/jdemeyer/local CC=gcc-4.1.2 Thread model: posix gcc version 4.4.0 20080916 (experimental) (GCC) -- Summary: Conversion double - unsigned long long - unsigned - double gives wrong results Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jdemeyer at cage dot ugent dot be GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37544
[Bug c/37544] Conversion double - unsigned long long - unsigned - double gives wrong results
--- Comment #1 from jdemeyer at cage dot ugent dot be 2008-09-16 16:40 --- Created an attachment (id=16339) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16339action=view) Testcase -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37544
[Bug c/37544] Conversion double - unsigned long long - unsigned - double gives wrong results
--- Comment #3 from jdemeyer at cage dot ugent dot be 2008-09-16 18:39 --- In fact, with -mno-sse the problem disappears for me too. I *do* get the problem with gcc -std=c99 -O1 -march=i386 -msse2 -mfpmath=387 -- jdemeyer at cage dot ugent dot be changed: What|Removed |Added Component|target |c http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37544
[Bug inline-asm/37195] different variables get the same memory address in inline assembly
--- Comment #4 from jdemeyer at cage dot ugent dot be 2008-09-03 07:57 --- Created an attachment (id=16200) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16200action=view) Testcase for powerpc-unknown-linux-gnu Also fails on powerpc: $ gcc -O1 test37195-powerpc.i -save-temps -c -o test37195-powerpc.o test37195-powerpc.s: Assembler messages: test37195-powerpc.s:119: Error: ASM 2: %1 and %5 are both equal to 16(1) test37195-powerpc.s:192: Error: ASM 3: %2 and %5 are both equal to 16(1) $ gcc -v Using built-in specs. Target: powerpc-unknown-linux-gnu Configured with: /var/tmp/portage/sys-devel/gcc-4.2.4/work/gcc-4.2.4/configure --prefix=/usr --bindir=/usr/powerpc-unknown-linux-gnu/gcc-bin/4.2.4 --includedir=/usr/lib/gcc/powerpc-unknown-linux-gnu/4.2.4/include --datadir=/usr/share/gcc-data/powerpc-unknown-linux-gnu/4.2.4 --mandir=/usr/share/gcc-data/powerpc-unknown-linux-gnu/4.2.4/man --infodir=/usr/share/gcc-data/powerpc-unknown-linux-gnu/4.2.4/info --with-gxx-include-dir=/usr/lib/gcc/powerpc-unknown-linux-gnu/4.2.4/include/g++-v4 --host=powerpc-unknown-linux-gnu --build=powerpc-unknown-linux-gnu --enable-altivec --enable-nls --without-included-gettext --with-system-zlib --disable-checking --disable-werror --enable-secureplt --disable-multilib --enable-libmudflap --disable-libssp --disable-libgcj --enable-languages=c,c++,treelang,fortran --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu Thread model: posix gcc version 4.2.4 (Gentoo 4.2.4 p1.0) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug inline-asm/37195] unrelated variables get the same memory address in inline assembly
--- Comment #3 from jdemeyer at cage dot ugent dot be 2008-09-02 08:52 --- Created an attachment (id=16187) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16187action=view) Further testcase simplification The third testcase uses only rm and =rm constraints, which means that it might not be specific to i386 targets. I still have to try other targets. Note that the bug only occurs if there are sufficiently many registers in the clobber list (otherwise the compiler just uses registers for everything). -- jdemeyer at cage dot ugent dot be changed: What|Removed |Added Attachment #16183|0 |1 is obsolete|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug inline-asm/37195] unrelated variables get the same memory address in inline assembly
--- Comment #2 from jdemeyer at cage dot ugent dot be 2008-09-01 18:18 --- Created an attachment (id=16183) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16183action=view) Better and simpler test case The second test case, asmtest2.i exhibits the bug on even more versions of gcc. To run the testcase, do gcc -O1 -save-temps asmtest2.i -o asmtest2 Consider the following piece of inline assembly (the second one of asmtest2.i): asm(# ASM 2\n movl %5, %2\n movl %4, %0\n movl %0, %1\n movl %3, %0\n : =a (c0), =rm (c1), =rm (c2) : rm (b0), rm (b1), 0 (b2) : cc, %esi, %edi, %edx ); gcc 4.3.2 compiles this as movl %eax, -40(%ebp) movl -24(%ebp), %eax movl %eax, -44(%ebp) movl -40(%ebp), %eax Note that %2 and %3 are both stored in -40(%ebp). I think this is a bug. I have tried this with the following versions of gcc, all of which have the bug: 3.4.6, 4.0.3, 4.1.2, 4.2.4, 4.3.1, 4.3.2 -- jdemeyer at cage dot ugent dot be changed: What|Removed |Added Attachment #16123|0 |1 is obsolete|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug inline-asm/37195] unrelated variables get the same memory address in inline assembly
-- jdemeyer at cage dot ugent dot be changed: What|Removed |Added Severity|normal |major http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug inline-asm/37195] unrelated variables get the same memory address in inline assembly
-- jdemeyer at cage dot ugent dot be changed: What|Removed |Added CC||jdemeyer at cage dot ugent ||dot be Severity|major |normal Version|4.3.2 |4.4.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug inline-asm/37195] New: unrelated variables get the same memory address in inline assembly
In the following inline assembly statement (the second one in the attached program), the operands %0 and %5 are stored in exactly the same memory address -44(%ebp), even though they refer to different variables (and all the output constraints have the earlyclobber modifier). asm( shrdl %6, %4, %3\n movl %3, %0\n movl %5, %2\n shrdl %6, %2, %1\n shrl %6, %2\n : =rm (d0), =r (d1), =r (d2) : 2 (c0), 1 (c1), g (c2), cI (s) : %eax, %esi, %edi, cc ); This code is compiled as shrdl %cl, %edx, %ebx movl %ebx, -40(%ebp) movl -40(%ebp), %ebx shrdl %cl, %ebx, %edx shrl %cl, %ebx Command line: gcc-4.2.4 -O1 -save-temps asmtest.c -c -o asmtest.o Note: gcc 4.3.1 does not seem to have this problem. Output of gcc -v: Using built-in specs. Target: i686-pc-linux-gnu Configured with: /var/tmp/portage/sys-devel/gcc-4.2.4/work/gcc-4.2.4/configure --prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.2.4 --includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.2.4/include --datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.2.4 --mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.2.4/man --infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.2.4/info --with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.2.4/include/g++-v4 --host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec --enable-nls --without-included-gettext --with-system-zlib --disable-checking --disable-werror --enable-secureplt --disable-multilib --enable-libmudflap --disable-libssp --disable-libgcj --with-arch=i686 --enable-languages=c,c++,treelang,fortran --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu Thread model: posix gcc version 4.2.4 (Gentoo 4.2.4) -- Summary: unrelated variables get the same memory address in inline assembly Product: gcc Version: 4.2.4 Status: UNCONFIRMED Severity: normal Priority: P3 Component: inline-asm AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: jdemeyer at cage dot ugent dot be GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
[Bug inline-asm/37195] unrelated variables get the same memory address in inline assembly
--- Comment #1 from jdemeyer at cage dot ugent dot be 2008-08-21 21:16 --- Created an attachment (id=16123) -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16123action=view) Source code which shows the problem -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37195
