https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94977
Bug ID: 94977 Summary: Some X86 inline assembly modifiers are not documented in the web documentation Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: craig.topper at gmail dot com Target Milestone: --- gcc supports some modifiers for inline assembly on X86 that are not documented in the table at 6.47.2.8 x86 Operand Modifiers here https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html For example gcc supports %x0 in inline assembly to indicate to always print a register as its xmm name. Similar there is also %t0 and %g0 for ymm and zmm respectively.