Index: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -6631,10 +6631,9 @@
                          Value *RHS, const Twine &Name, Instruction *I) {
     Value *Op = createOp(Builder, RdxKind, LHS, RHS, Name);
     if (RecurrenceDescriptor::isIntMinMaxRecurrenceKind(RdxKind)) {
-      if (auto *Sel = dyn_cast<SelectInst>(Op)) {
-        propagateIRFlags(Sel->getCondition(),
-                         cast<SelectInst>(I)->getCondition());
-      }
+      if (auto *Sel = dyn_cast<SelectInst>(Op))
+        if (auto *SelI = dyn_cast<SelectInst>(I))
+          propagateIRFlags(Sel->getCondition(), SelI->getCondition());
     }
     propagateIRFlags(Op, I);
     return Op;
Index: llvm/test/Transforms/SLPVectorizer/slp-umax-rdx-crash.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SLPVectorizer/slp-umax-rdx-crash.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -slp-vectorizer -S < %s | FileCheck %s
+
+declare i32 @llvm.smin.i32(i32, i32)
+declare i32 @llvm.umin.i32(i32, i32)
+
+; Given LLVM IR caused crash in SLP.
+define void @test() {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = call <4 x i32> @llvm.smin.v4i32(<4 x i32> undef, <4 x i32> <i32 3, i32 2, i32 1, i32 0>)
+; CHECK-NEXT:    [[TMP1:%.*]] = sub nsw <4 x i32> undef, [[TMP0]]
+; CHECK-NEXT:    [[TMP2:%.*]] = call i32 @llvm.vector.reduce.umin.v4i32(<4 x i32> [[TMP1]])
+; CHECK-NEXT:    [[OP_EXTRA:%.*]] = icmp ult i32 [[TMP2]], 77
+; CHECK-NEXT:    [[OP_EXTRA1:%.*]] = select i1 [[OP_EXTRA]], i32 [[TMP2]], i32 77
+; CHECK-NEXT:    [[E:%.*]] = icmp ugt i32 [[OP_EXTRA1]], 1
+; CHECK-NEXT:    ret void
+;
+entry:
+  %smin0 = call i32 @llvm.smin.i32(i32 undef, i32 0)
+  %smin1 = call i32 @llvm.smin.i32(i32 undef, i32 1)
+  %smin2 = call i32 @llvm.smin.i32(i32 undef, i32 2)
+  %smin3 = call i32 @llvm.smin.i32(i32 undef, i32 3)
+  %a = sub nsw i32 undef, %smin0
+  %b = sub nsw i32 undef, %smin1
+  %c = sub nsw i32 undef, %smin2
+  %d = sub nsw i32 undef, %smin3
+  %umin0 = call i32 @llvm.umin.i32(i32 %d, i32 %c)
+  %umin1 = call i32 @llvm.umin.i32(i32 %umin0, i32 %b)
+  %umin2 = call i32 @llvm.umin.i32(i32 %umin1, i32 %a)
+  %umin3 = call i32 @llvm.umin.i32(i32 %umin2, i32 77)
+  %e = icmp ugt i32 %umin3, 1
+  ret void
+}
+