Bug 21037 – AVX code sometimes fails to set VEX prefix

Suddenly this started failing in the test suite. The failing code is extracted from runnable/testxmm.d: ------------------------------------ import core.simd; import core.stdc.string; import core.stdc.stdio; version (D_AVX) { void foo_byte32(byte t, byte s) { byte32 f = s; (***) auto p = cast(byte*)&f; foreach (i; 0 .. 32) { printf("[%d]: %d\n", i, p[i]); assert(p[i] == s); } } void main() { foo_byte32(5, -10); } } The (***) is where the problem is, the MOVDQA instruction generated should be VMOVDQA.

dlang/dmd pull request #11406 "fix Issue 21037 - AVX code sometimes fails to set VEX prefix" was merged into master: - 9f6bd4504a85ef86b84f41a36e8759c8cec02bb7 by Walter Bright: fix Issue 21037 - AVX code sometimes fails to set VEX prefix https://github.com/dlang/dmd/pull/11406