InstCombine: canonicalize sext-and --> select

                          sext-not-and --> select.

Patch by Muhammad Tauqir Ahmad.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173901 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 0 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index c1e60d4..bf065fe 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1245,6 +1245,34 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
       }
   }
 
+  {
+    Value *X = 0;
+    bool OpsSwapped = false;
+    // Canonicalize SExt or Not to the LHS
+    if (match(Op1, m_SExt(m_Value())) ||
+        match(Op1, m_Not(m_Value()))) {
+      std::swap(Op0, Op1);
+      OpsSwapped = true;
+    }
+
+    // Fold (and (sext bool to A), B) --> (select bool, B, 0)
+    if (match(Op0, m_SExt(m_Value(X))) &&
+        X->getType()->getScalarType()->isIntegerTy(1)) {
+      Value *Zero = Constant::getNullValue(Op1->getType());
+      return SelectInst::Create(X, Op1, Zero);
+    }
+
+    // Fold (and ~(sext bool to A), B) --> (select bool, 0, B)
+    if (match(Op0, m_Not(m_SExt(m_Value(X)))) &&
+        X->getType()->getScalarType()->isIntegerTy(1)) {
+      Value *Zero = Constant::getNullValue(Op0->getType());
+      return SelectInst::Create(X, Zero, Op1);
+    }
+
+    if (OpsSwapped)
+      std::swap(Op0, Op1);
+  }
+
   return Changed ? &I : 0;
 }