[Bug inline-asm/77607] New: Aarch64 LDP operand rejected incorrectly

["hyc at symas dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77607

            Bug ID: 77607
           Summary: Aarch64 LDP operand rejected incorrectly
           Product: gcc
           Version: 4.9.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: inline-asm
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hyc at symas dot com
  Target Milestone: ---

This sequence:

{uint8x16_t _a, _b, _c, _d;
    __asm__("ldp %0, %1, %4\n\t"
        "ldp %2, %3, %4, #32\n\t" : "=w"(_a), "=w"(_b), "=w"(_c), "=w"(_d) :
"Ump"(state.k) :);

Generates this code:

        ldp v1, v4, [x0]
        ldp v0, v2, [x0], #32

And gets this error:

/tmp/ccQYB8nY.s:172: Error: operand 1 should be a floating-point register --
`ldp v1,v4,[x0]'
/tmp/ccQYB8nY.s:173: Error: operand 1 should be a floating-point register --
`ldp v0,v2,[x0],#32'

According to the docs, "w" is the correct constraint character to use for FP or
SIMD register. So either gas is rejecting this incorrectly, or gcc is
generating the wrong register name for this constraint.