1 files changed, 24 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index ef84e0c..b8ff6be 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -2902,6 +2902,24 @@ static bool isSignedMinMaxClamp(const Value *Select, const Value *&In,
   return CLow->sle(*CHigh);
 }
 
+static bool isSignedMinMaxIntrinsicClamp(const IntrinsicInst *II,
+                                         const APInt *&CLow,
+                                         const APInt *&CHigh) {
+  assert((II->getIntrinsicID() == Intrinsic::smin ||
+          II->getIntrinsicID() == Intrinsic::smax) && "Must be smin/smax");
+
+  Intrinsic::ID InverseID = getInverseMinMaxIntrinsic(II->getIntrinsicID());
+  auto *InnerII = dyn_cast<IntrinsicInst>(II->getArgOperand(0));
+  if (!InnerII || InnerII->getIntrinsicID() != InverseID ||
+      !match(II->getArgOperand(1), m_APInt(CLow)) ||
+      !match(InnerII->getArgOperand(1), m_APInt(CHigh)))
+    return false;
+
+  if (II->getIntrinsicID() == Intrinsic::smin)
+    std::swap(CLow, CHigh);
+  return CLow->sle(*CHigh);
+}
+
 /// For vector constants, loop over the elements and find the constant with the
 /// minimum number of sign bits. Return 0 if the value is not a vector constant
 /// or if any element was not analyzed; otherwise, return the count for the
@@ -3242,6 +3260,12 @@ static unsigned ComputeNumSignBitsImpl(const Value *V,
 
           // Absolute value reduces number of sign bits by at most 1.
           return Tmp - 1;
+        case Intrinsic::smin:
+        case Intrinsic::smax: {
+          const APInt *CLow, *CHigh;
+          if (isSignedMinMaxIntrinsicClamp(II, CLow, CHigh))
+            return std::min(CLow->getNumSignBits(), CHigh->getNumSignBits());
+        }
         }
       }
     }