diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -6509,6 +6509,11 @@
   if (ValAssumedPoison == V)
     return true;
 
+  auto *IAssumedPoison = dyn_cast<Instruction>(ValAssumedPoison);
+  auto *IV = dyn_cast<Instruction>(V);
+  if (IAssumedPoison && IV && IAssumedPoison->isIdenticalTo(IV))
+    return true;
+
   const unsigned MaxDepth = 2;
   if (Depth >= MaxDepth)
     return false;
diff --git a/llvm/test/Transforms/InstCombine/signed-truncation-check.ll b/llvm/test/Transforms/InstCombine/signed-truncation-check.ll
--- a/llvm/test/Transforms/InstCombine/signed-truncation-check.ll
+++ b/llvm/test/Transforms/InstCombine/signed-truncation-check.ll
@@ -661,7 +661,7 @@
 ; CHECK-NEXT:    call void @use32(i32 [[T4]])
 ; CHECK-NEXT:    [[T5:%.*]] = icmp eq i32 [[T4]], [[ARG]]
 ; CHECK-NEXT:    call void @use1(i1 [[T5]])
-; CHECK-NEXT:    [[T6:%.*]] = select i1 [[T2]], i1 [[T5]], i1 false
+; CHECK-NEXT:    [[T6:%.*]] = and i1 [[T2]], [[T5]]
 ; CHECK-NEXT:    ret i1 [[T6]]
 ;
   %t1 = trunc i32 %arg to i8