[LVI][CVP] Add support for abs/nabs select pattern flavor

Based on ConstantRange support added in D61084, we can now handle
abs and nabs select pattern flavors in LVI.

Differential Revision: https://reviews.llvm.org/D61794

llvm-svn: 360700

1 files changed, 22 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index e7ca69150c0..4f6a3441701 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -893,7 +893,28 @@ bool LazyValueInfoImpl::solveBlockValueSelect(ValueLatticeElement &BBLV,
       return true;
     }
 
-    // TODO: ABS, NABS from the SelectPatternResult
+    if (SPR.Flavor == SPF_ABS) {
+      if (LHS == SI->getTrueValue()) {
+        BBLV = ValueLatticeElement::getRange(TrueCR.abs());
+        return true;
+      }
+      if (LHS == SI->getFalseValue()) {
+        BBLV = ValueLatticeElement::getRange(FalseCR.abs());
+        return true;
+      }
+    }
+
+    if (SPR.Flavor == SPF_NABS) {
+      ConstantRange Zero(APInt::getNullValue(TrueCR.getBitWidth()));
+      if (LHS == SI->getTrueValue()) {
+        BBLV = ValueLatticeElement::getRange(Zero.sub(TrueCR.abs()));
+        return true;
+      }
+      if (LHS == SI->getFalseValue()) {
+        BBLV = ValueLatticeElement::getRange(Zero.sub(FalseCR.abs()));
+        return true;
+      }
+    }
   }
 
   // Can we constrain the facts about the true and false values by using the