Bug 13383 – wrong code with -O with ints, longs and bitwise operations

Consider the following code (minimized example): ----- void main () { foreach (k; 32..33) { if (1L & (1L << k)) { assert (false); } } } ----- Obviously, 1L & (1L << k) must be true only when k = 0. Still, with k = 32, it produces a true value when compiled with "dmd -O". All is well without "-O". It is reproducible for me with DMD 2.064.2-2.066.0 on Win32. It works for me with DMD 2.063.2. So, the issue was probably introduced between 2.063.2 and 2.064.2.

Created attachment 1390 A small example demonstrating the problem.

The compiler incorrectly optimizes 1L & (1L << k) to 1 btst k, which is only valid when 1L fits in a register. https://github.com/D-Programming-Language/dmd/pull/3934

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/e14242906651c07247e41e37de1d27a18b81e54b Fix Issue 13383 - wrong code with -O with ints, longs and bitwise operations Converting '(1 << a) & b' to 'b btst a' is only valid when the constant fits in a register. https://github.com/D-Programming-Language/dmd/commit/10edd8d6121ffffd916bc94768723b15c6a321c1 Merge pull request #3934 from yebblies/issue13383 Issue 13383 - wrong code with -O with ints, longs and bitwise operations

Commit pushed to 2.066 at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/d1a3b4e624971de83456d1b1e2a84dc480e54e94 Merge pull request #3934 from yebblies/issue13383 Issue 13383 - wrong code with -O with ints, longs and bitwise operations