re PR rtl-optimization/11001 (global register %edi versus string builtins)

re PR rtl-optimization/11001 (global register %edi versus string builtins)

gcc/
	PR 11001
	* config/i386/i386.md (strmov): Check for esi and edi usage.
	* config/i386/i386.c (decide_alg): Check whether we can use a
	rep prefix and adjust algorithm choice accordingly.
	(ix86_expand_strlen): Check for eax, ecx, and edi usage.

gcc/testsuite/
	PR 11001
	* gcc.target/i386/pr11001-strlen-1.c: New testcase.
	* gcc.target/i386/pr11001-strlen-2.c: New testcase.
	* gcc.target/i386/pr11001-strlen-3.c: New testcase.
	* gcc.target/i386/pr11001-memset-1.c: New testcase.
	* gcc.target/i386/pr11001-memset-2.c: New testcase.
	* gcc.target/i386/pr11001-memset-3.c: New testcase.
	* gcc.target/i386/pr11001-memcpy-1.c: New testcase.
	* gcc.target/i386/pr11001-memcpy-2.c: New testcase.
	* gcc.target/i386/pr11001-memcpy-3.c: New testcase.

From-SVN: r129265