[ARM32] Display wrong register number for double registers #2191

From @hqueue on May 16, 2017 11:47

For ARM32, double register number is not shown correctly in JitDump, JitDisasm and etc.

• An example from coreclr unit test.

  $ COMPlus_JitDisasm=DblAdd COMPlus_JitDump=DblAdd  ./corerun 
  tests/JIT/CodeGenBringUpTests/DblAdd/DblAdd.exe
  ...(omitted)...
  IN0001: 000006  EE30 0B01      vadd    d0, d0, d2
  ...(omitted)...
  IN0001: 000006      vadd    d0, d0, d2
  

  However above instruction encoding means vadd d0, d0, d1.

• Another example from recent PR for ryujit/arm32.
  I was confused with below example ([RyuJIT/ARM32] Enable casting from small int to float coreclr#11643 (comment)) in the PR.

  IN0074: 000180  EEB8 4BC4      vcvt.i2d d8, s8  
  

  This means vcvt.i2d d4, s8, i.e. single-float register number is correct, but double register number is incorrectly displayed.

Both LegacyJIT and RyuJIT have same problem.

Copied from original issue: dotnet/coreclr#11646