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Copy changes from doc/tm.texi to doc/tm.texi.in

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* doc/tm.texi.in (Condition Code Status): Update documention for
	relative locations of cc0-setter and cc0-user.

From-SVN: r208205
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H.J. Lu 2014-02-27 19:54:56 +00:00 committed by H.J. Lu
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@ -1,3 +1,8 @@
2014-02-27 H.J. Lu <hongjiu.lu@intel.com>
* doc/tm.texi.in (Condition Code Status): Update documention for
relative locations of cc0-setter and cc0-user.
2014-02-27 Jeff Law <law@redhat.com>
PR rtl-optimization/52714

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gcc/doc/tm.texi.in
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@ -4484,8 +4484,13 @@ most instructions do not affect it. The latter category includes
most RISC machines.
The implicit clobbering poses a strong restriction on the placement of
the definition and use of the condition code, which need to be in adjacent
insns for machines using @code{(cc0)}. This can prevent important
the definition and use of the condition code. In the past the definition
and use were always adjacent. However, recent changes to support trapping
arithmatic may result in the definition and user being in different blocks.
Thus, there may be a @code{NOTE_INSN_BASIC_BLOCK} between them. Additionally,
the definition may be the source of exception handling edges.
These restrictions can prevent important
optimizations on some machines. For example, on the IBM RS/6000, there
is a delay for taken branches unless the condition code register is set
three instructions earlier than the conditional branch. The instruction