https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67456
Bug ID: 67456 Summary: wrong code at -O2 and -O3 on x86_64-linux-gnu Product: gcc Version: 6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu Target Milestone: --- The current gcc trunk miscompiles the following code on x86_64-linux-gnu at -O2 and -O3 in both 32-bit and 64-bit modes. This is a regression from 5.2.x. $ gcc-trunk -v Using built-in specs. COLLECT_GCC=gcc-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk --enable-languages=c,c++ --disable-werror --enable-multilib Thread model: posix gcc version 6.0.0 20150904 (experimental) [trunk revision 227491] (GCC) $ $ gcc-trunk -Os small.c; ./a.out -1 $ gcc-5.2 -O2 small.c; ./a.out -1 $ $ gcc-trunk -O2 small.c $ ./a.out -2 $ --------------------------------- int printf (const char *, ...); short d = -1; char e, h; int main () { char i; int j = 0; h = e = d; i = e < j ? e : e << 1; printf ("%d\n", i); return 0; }