re PR rtl-optimization/93088 (Compile time hog on gcc/testsuite/gcc.target/i386/pr56348.c w/ -O3 -funroll-loops -fno-tree-dominator-opts -fno-tree-vrp)

	PR rtl-optimization/93088
	* loop-iv.c (find_single_def_src): Punt after looking through
	128 reg copies for regs with single definitions.  Move definitions
	to first uses.

	* gcc.target/i386/pr93088.c: New test.

From-SVN: r279854