David Majnemer 5624046453 InstCombine: Simplify (A ^ B) or/and (A ^ B ^ C) ... While we can already transform A | (A ^ B) into A | B, things get bad once we have (A ^ B) | (A ^ B ^ Cst) because reassociation will morph this into (A ^ B) | ((A ^ Cst) ^ B). Our existing patterns fail once this happens. To fix this, we add a new pattern which looks through the tree of xor binary operators to see that, in fact, there exists a redundant xor operation. What follows bellow is a correctness proof of the transform using CVC3. $ cat t.cvc A, B, C : BITVECTOR(64); QUERY BVXOR(A, B) | BVXOR(BVXOR(B, C), A) = BVXOR(A, B) | C; QUERY BVXOR(BVXOR(A, C), B) | BVXOR(A, B) = BVXOR(A, B) | C; QUERY BVXOR(A, B) & BVXOR(BVXOR(B, C), A) = BVXOR(A, B) & ~C; QUERY BVXOR(BVXOR(A, C), B) & BVXOR(A, B) = BVXOR(A, B) & ~C; $ cvc3 < t.cvc Valid. Valid. Valid. Valid. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214342 91177308-0d34-0410-b5e6-96231b3b80d8		2014-07-30 21:26:37 +00:00
..
CMakeLists.txt
InstCombine.h	This patch implements optimization as mentioned in PR19753: Optimize comparisons with "ashr/lshr exact" of a constanst.	2014-07-22 19:19:36 +00:00
InstCombineAddSub.cpp	Fix Typo (first commit to test commit access)	2014-07-17 06:09:34 +00:00
InstCombineAndOrXor.cpp	InstCombine: Simplify (A ^ B) or/and (A ^ B ^ C)	2014-07-30 21:26:37 +00:00
InstCombineCalls.cpp	Canonicalization for @llvm.assume	2014-07-25 21:45:17 +00:00
InstCombineCasts.cpp	Fix comment in InstCombiner::visitAddrSpaceCast.	2014-07-16 01:34:21 +00:00
InstCombineCompares.cpp	This patch implements optimization as mentioned in PR19753: Optimize comparisons with "ashr/lshr exact" of a constanst.	2014-07-22 19:19:36 +00:00
InstCombineLoadStoreAlloca.cpp	AA metadata refactoring (introduce AAMDNodes)	2014-07-24 12:16:19 +00:00
InstCombineMulDivRem.cpp
InstCombinePHI.cpp
InstCombineSelect.cpp
InstCombineShifts.cpp	fixed typo in comment	2014-07-22 04:57:06 +00:00
InstCombineSimplifyDemanded.cpp
InstCombineVectorOps.cpp	fixed some typos	2014-07-07 22:13:58 +00:00
InstCombineWorklist.h
InstructionCombining.cpp	Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges."	2014-07-21 17:06:51 +00:00
LLVMBuild.txt
Makefile