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authorSanjay Patel <spatel@rotateright.com>2017-04-24 18:24:36 +0000
committerSanjay Patel <spatel@rotateright.com>2017-04-24 18:24:36 +0000
commit0889225f51791cb4e8219a9dd96c3144122348ec (patch)
treecd69e38b730176c23efafa34134de4931b720ef9 /llvm/lib/Analysis/InstructionSimplify.cpp
parentf2fc5b068e011455a4857cdc9349055c5a8b5221 (diff)
downloadbcm5719-llvm-0889225f51791cb4e8219a9dd96c3144122348ec.tar.gz
bcm5719-llvm-0889225f51791cb4e8219a9dd96c3144122348ec.zip
[InstSimplify] move (A & ~B) | (A ^ B) -> (A ^ B) from InstCombine
This is a straight cut and paste, but there's a bigger problem: if this fold exists for simplifyOr, there should be a DeMorganized version for simplifyAnd. But more than that, we have a patchwork of ad hoc logic optimizations in InstCombine. There should be some structure to ensure that we're not missing sibling folds across and/or/xor. llvm-svn: 301213
Diffstat (limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')
-rw-r--r--llvm/lib/Analysis/InstructionSimplify.cpp13
1 files changed, 13 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 2259fbaeb98..0f60f1ba8a9 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1877,6 +1877,19 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const Query &Q,
(A == Op0 || B == Op0))
return Constant::getAllOnesValue(Op0->getType());
+ // (A & ~B) | (A ^ B) -> (A ^ B)
+ // (~B & A) | (A ^ B) -> (A ^ B)
+ if (match(Op0, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
+ match(Op1, m_Xor(m_Specific(A), m_Specific(B))))
+ return Op1;
+
+ // Commute the 'or' operands.
+ // (A ^ B) | (A & ~B) -> (A ^ B)
+ // (A ^ B) | (~B & A) -> (A ^ B)
+ if (match(Op1, m_c_And(m_Value(A), m_Not(m_Value(B)))) &&
+ match(Op0, m_Xor(m_Specific(A), m_Specific(B))))
+ return Op0;
+
if (auto *ICILHS = dyn_cast<ICmpInst>(Op0)) {
if (auto *ICIRHS = dyn_cast<ICmpInst>(Op1)) {
if (Value *V = SimplifyOrOfICmps(ICILHS, ICIRHS))
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