Compiler version and platform:
Intel(R) C Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 17.0.1.132 Build 20161005
$ icc -O2 small.c; ./a.out 0 $ $ icc -O3 small.c; ./a.out -1 $ $ cat small.c int printf (const char *, ...); int a, b, c, d = 1, e, f; void foo () { for (c = 0; c < 2; c++) { if (d) { if (a && e) continue; b = c; c = b; } break; } } int main () { foo (); printf ("%d\n", c); for (f = 0; f < 2; f++) ; return 0; } $