Bug 12051 – Wrong code with ?: resulting in char on x86-64

A wrong code issue was found in DCD project commit e7f3952. The code where the compiler fails to produce correct code is in astconverter.d:558 foreach (i, s; importInfo.importParts) { immutable kind = i + 1 < importInfo.importParts.length ? CompletionKind.packageName : CompletionKind.moduleName; // Begin compiler bug workaround (this is part of the next commit, not e7f3952) if (kind == 'L') std.stdio.writeln("ERROR ", kind); ... } CompletionKind is a char enum (located in messages.d), CompletionKind.packageName = 'P', CompletionKind.moduleName = 'M' -------------------------------------------------- The assembly produced for this part of the code: lea 0x1(%rbx),%rcx cmp -0x1c0(%rbp),%rcx sbb %rsi,%rsi and $0x3,%dh <---------- wrong register, should be sil, not dh add $0x4d,%sil This code is the same on commit e7f3952 in an optimized build and on commit 2745763 in a non-optimized build. However it is different in an optimized for commit 2745763. The optimized code is: lea 0x1(%r12),%rcx cmp -0xa0(%rbp),%rcx sbb %r13,%r13 and $0x3,%r13b add $0x4d,%r13b The code in the optimized build doesn't have the issue. And it runs as expected. -------------------------------------------------- Original discussion https://github.com/Hackerpilot/DCD/issues/92

BTW, inline and possibly other flags are not required to reproduce the issue. And removing it from the build script will speed up the compilation greatly.

Slowly, slowly reducing with dustmite.

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/558ff1217863936fbb3df9d01cb0bc4f8a11cd14 Fix Issue 12051 - Wrong code with ?: resulting in char on x86-64 https://github.com/D-Programming-Language/dmd/commit/1fdd3c6ace7ea0c5985d7c3041d4641b05b098df Merge pull request #3182 from yebblies/issue12051 Issue 12051 - Wrong code with ?: resulting in char on x86-64

Commit pushed to dmd-1.x at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/e39e0707f590fff45deebde81e5b34846ecdffed Merge pull request #3182 from yebblies/issue12051 Issue 12051 - Wrong code with ?: resulting in char on x86-64

Commit pushed to 2.065 at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/b1ba7340cf028a3fd9857de2980b6eb611c0caef Merge pull request #3182 from yebblies/issue12051 Issue 12051 - Wrong code with ?: resulting in char on x86-64