6 Commits

Author	SHA1	Message	Date
Benjamin Kramer	cfc0ad6e48	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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161728 91177308-0d34-0410-b5e6-96231b3b80d8	2012-08-11 19:05:13 +00:00
Manman Ren	ba86b13ad9	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 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161396 91177308-0d34-0410-b5e6-96231b3b80d8	2012-08-07 06:16:46 +00:00
Evan Cheng	97b5beb7fe	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 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147827 91177308-0d34-0410-b5e6-96231b3b80d8	2012-01-10 02:02:58 +00:00
Evan Cheng	bf34a5ec22	sext(undef) = 0, because the top bits will all be the same. ... zext(undef) = 0, because the top bits will be zero. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127649 91177308-0d34-0410-b5e6-96231b3b80d8	2011-03-15 02:22:10 +00:00
Evan Cheng	a63cde26ff	Teach machine cse to commute instructions. ... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121903 91177308-0d34-0410-b5e6-96231b3b80d8	2010-12-15 22:16:21 +00:00
Evan Cheng	fac4f1f181	Enable machine cse pass. ... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98132 91177308-0d34-0410-b5e6-96231b3b80d8	2010-03-10 03:07:41 +00:00