* auto-inc-dec.c, config/arm/arm.c,
	config/m32r/constraints.md, config/mips/mips.md,
	config/rs6000/rs6000.c, cselib.c, dce.c, df-core.c,
	df-problems.c, df-scan.c, df.h, dse.c, gimplify.c,
	tree-if-conv.c, tree-ssa-sccvn.c, tree-ssa.c: Fix comment
	typos.  Follow spelling conventions.
	* doc/invoke.texi, doc/rtl.texi: Fix typos.

From-SVN: r126439