6 Commits

Author	SHA1	Message	Date
Benjamin Kramer	b338b22e72	PR13578: Teach MachineCSE that instructions that use a constant register can be CSE'd safely. ... This is common e.g. when doing rip-relative addressing on x86_64. llvm-svn: 161728	2012-08-11 19:05:13 +00:00
Manman Ren	5d43c19d9e	MachineCSE: Update the heuristics for isProfitableToCSE. ... If the result of a common subexpression is used at all uses of the candidate expression, CSE should not increase the live range of the common subexpression. rdar://11393714 and rdar://11819721 llvm-svn: 161396	2012-08-07 06:16:46 +00:00
Evan Cheng	7855c5d08f	Allow machine-cse to look across MBB boundary when cse'ing instructions that ... define physical registers. It's currently very restrictive, only catching cases where the CE is in an immediate (and only) predecessor. But it catches a surprising large number of cases. rdar://10660865 llvm-svn: 147827	2012-01-10 02:02:58 +00:00
Evan Cheng	bac3e87eaa	sext(undef) = 0, because the top bits will all be the same. ... zext(undef) = 0, because the top bits will be zero. llvm-svn: 127649	2011-03-15 02:22:10 +00:00
Evan Cheng	68e1ed8752	Teach machine cse to commute instructions. ... llvm-svn: 121903	2010-12-15 22:16:21 +00:00
Evan Cheng	668ceddeec	Enable machine cse pass. ... llvm-svn: 98132	2010-03-10 03:07:41 +00:00