https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68955
Bug ID: 68955 Summary: wrong code at -O3 on x86-64-linux-gnu in 32-bit mode Product: gcc Version: 6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: chengniansun at gmail dot com Target Milestone: --- The following code is miscompiled by the gcc trunk at -O3 on x86-64-linux-gnu in 32-bit mode (not in 64-bit mode). $: 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 20151217 (experimental) [trunk revision 231731] (GCC) $: $: gcc-trunk -O3 -m32 -w small.c ; ./a.out 0 $: gcc-trunk -w small.c ; ./a.out 1 $: cat small.c int printf (const char *, ...); int a, b, c, d, g, m; int i[7][7][5] = { {{5}}, {{5}}, {{5}, {5}, {5}, {5}, {5}, {-1}} }; static int j = 11; short e, f, h, k, l; static void fn1 () { for (; e < 5; e++) for (h = 3; h; h--) { for (g = 1; g < 6; g++) { m = c == 0 ? b : b / c; i[e][1][e] = i[1][1][1] | (m & l) && f; } for (k = 0; k < 6; k++) { for (d = 0; d < 6; d++) i[1][e][h] = i[h][k][e] >= l; i[e + 2][h + 3][e] = 6 & l; i[2][1][2] = a; for (; j < 5;) for (;;) ; } } } int main () { fn1 (); printf ("%d\n", i[1][0][2]); return 0; } $: