Bug 13784 – Wrong code with modulo operation and optimisations enabled

assertions passes when compiled with no flags and fails when compiled with -O ``` long modulo24 (long ticks) { const TicksPerDay = 864000000000; ticks %= TicksPerDay; if (ticks < 0) ticks += TicksPerDay; return ticks; } unittest { assert (modulo24(-141600000000) == 722400000000); } ``` Checking assembly reveals wrong optimisation via replacing modulo with multiplication. Issue present in both D1 and D2 compilers. Workaround is to avoid modulo operation with negative numbers.

Extra issue is that even with workaround it sometimes does broken optimisation at if both -O and -inline are present (at the call site for modulo24)

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/61dd9d1fac47855a2fb6c1c79cd54c49a47db306 fix Issue 13784 - Wrong code with modulo operation and optimisations enabled https://github.com/D-Programming-Language/dmd/commit/1b8db262262352b00d027c93aee00b669b290931 Merge pull request #4214 from WalterBright/fix13784 fix Issue 13784 - Wrong code with modulo operation and optimisations ena...

Reopening as D1-only until fix is merged into dmd-1.x :P

Commit pushed to dmd-1.x at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/012695720948b8633e054e63485ccb091b3847d5 fix Issue 13784 - Wrong code with modulo operation and optimisations enabled

Commits pushed to 2.067 at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/61dd9d1fac47855a2fb6c1c79cd54c49a47db306 fix Issue 13784 - Wrong code with modulo operation and optimisations enabled https://github.com/D-Programming-Language/dmd/commit/1b8db262262352b00d027c93aee00b669b290931 Merge pull request #4214 from WalterBright/fix13784