[PATCH] [PowerPC] Fix __tls_get_addr sequence to avoid register assignment issues

[hfinkel at anl.gov]

> Maybe it needs the full clobber mask associated with a regular function call? Based on this crash, it looks like it at least also clobbers r4.


To answer my own question, Google seems to say that glibc/sysdeps/powerpc/tls-macros.h has this:

  #define __TLS_CALL_CLOBBERS						      \
  	"0", "4", "5", "6", "7", "8", "9", "10", "11", "12",		      \
  	"lr", "ctr", "cr0", "cr1", "cr5", "cr6", "cr7"

(and that's what is used by the TLS_LD/TLS_GD macros (etc.) that contain calls to __tls_get_addr.

Let's define a minimal CC reg mask that only has these registers, and apply it to the pseudo that becomes the function call (or something like that).


http://reviews.llvm.org/D7491

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