bcm5719-llvm - Project Ortega BCM5719 LLVM

	Commit message (Collapse)	Author	Age	Files	Lines
*	[ValueTracking] Extend r251146 to catch a fairly common case	James Molloy	2015-10-26	1	-0/+13
	Even though we may not know the value of the shifter operand, it's possible we know the shifter operand is non-zero. This can allow us to infer more known bits - for example: %1 = load %p !range {1, 5} %2 = shl %q, %1 We don't know %1, but we do know that it is nonzero so %2[0] is known zero, and importantly %2 is known non-zero. Calling isKnownNonZero is nontrivially expensive so use an Optional to run it lazily and cache its result. llvm-svn: 251294