http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49379
Summary: warning from Mac OS X linker alignment lost for -ftree-vectorize optimization Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassig...@gcc.gnu.org ReportedBy: ne...@intrepid.com While running some tests on Mac OS X 10.6.7 I ran into the following warning from the linker: ld: warning: alignment lost in merging tentative definition _u_th_arr Test links without the warning if -fno-tree-vectorize option is provided when compiling the source. I didn't have a chance to verify that executable is correct as my test is hanging - there might be multiple reasons for it. Linker is: @(#)PROGRAM:ld PROJECT:ld64-123.2 llvm version 2.9svn, from Apple Clang 2.0 (build 139) I am attaching a small test program that I checked out against the snapshot of the compiler 4.7.0 20110604. Here is the output of the compile/link process: + snapshot/gcc/xgcc -B../bld/packed-opt/gcc/ -v Reading specs from ../bld/packed-opt/gcc/specs COLLECT_GCC=snapshot/gcc/xgcc COLLECT_LTO_WRAPPER=../bld/packed-opt/gcc/lto-wrapper Target: x86_64-apple-darwin10.7.4 Configured with: ../../src/gcc-4.7-20110604/configure --disable-bootstrap Thread model: posix gcc version 4.7.0 20110604 (experimental) (GCC) + snapshot/gcc/xgcc -B../bld/packed-opt/gcc/ -I. -O3 -c a.c + snapshot/gcc/xgcc -B../bld/packed-opt/gcc/ -I. -O3 -c b.c + snapshot/gcc/xgcc -B../bld/packed-opt/gcc/ -o a -O3 a.o b.o ld: warning: alignment lost in merging tentative definition _u_th_arr + snapshot/gcc/xgcc -B../bld/packed-opt/gcc/ -I. -O3 -fno-tree-vectorize -c a.c + snapshot/gcc/xgcc -B../bld/packed-opt/gcc/ -I. -O3 -fno-tree-vectorize -c b.c + snapshot/gcc/xgcc -B../bld/packed-opt/gcc/ -o a -O3 a.o b.o