• brooks's avatar
    Add a patch for upstream r300404: · 074555cb
    brooks authored
    Use correct registers for "A" inline asm constraint
    
    Summary:
    In PR32594, inline assembly using the 'A' constraint on x86_64 causes
    llvm to crash with a "Cannot select" stack trace.  This is because
    `X86TargetLowering::getRegForInlineAsmConstraint` hardcodes that 'A'
    means the EAX and EDX registers.
    
    However, on x86_64 it means the RAX and RDX registers, and on 16-bit x86
    (ia16?) it means the old AX and DX registers.
    
    Add new register classes in `X86RegisterInfo.td` to support these cases,
    and amend the logic in `getRegForInlineAsmConstraint` to cope with
    different subtargets.  Also add a test case, derived from PR32594.
    
    Submitted by:	dim
    074555cb