Handle internal functions in is_tm_pure_call

The upcoming changes to use internal functions for things like sqrt
caused a failure in gcc.dg/tm/20100610.c, because we were trying to get
call flags from the null gimple_call_fn of an IFN_SQRT call.  We've been
making fairly heavy use of internal functions for a while now so I think
this might be latent.

Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.

gcc/
	* trans-mem.c (is_tm_pure_call): Use gimple_call_flags for
	internal functions.

From-SVN: r229925

gcc/ChangeLog

 2015-11-07  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* trans-mem.c (is_tm_pure_call): Use gimple_call_flags for
+	internal functions.
+
+2015-11-07  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* builtins.def: #undef DEF_BUILTIN and DEF_BUILTIN_CHKP
 	* builtins.c, genmatch.c, tree-core.h: Don't undef them here.
 

gcc/trans-mem.c

@@ -266,6 +266,9 @@ is_tm_safe (const_tree x)
 static bool
 is_tm_pure_call (gimple *call)
 {
+  if (gimple_call_internal_p (call))
+    return (gimple_call_flags (call) & (ECF_CONST | ECF_TM_PURE)) != 0;
+
   tree fn = gimple_call_fn (call);
 
   if (TREE_CODE (fn) == ADDR_EXPR)