diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -13998,20 +13998,32 @@
   if (N0.isUndef())
     return DAG.getUNDEF(VT);
 
-  // If the input is a BUILD_VECTOR with all constant elements, fold this now.
-  // Only do this before legalize types, unless both types are integer and the
-  // scalar type is legal. Only do this before legalize ops, since the target
-  // maybe depending on the bitcast.
-  // First check to see if this is all constant.
-  // TODO: Support FP bitcasts after legalize types.
-  if (VT.isVector() &&
+  // If the input is a BUILD_VECTOR with all constant elements or SPLAT_VECTOR
+  // with a constant scalar, fold this now. Only do this before legalize types,
+  // unless both types are integer and the scalar type is legal. Only do this
+  // before legalize ops, since the target maybe depending on the bitcast.
+  // First check to see if this is all constant.  TODO: Support FP bitcasts
+  // after legalize types.
+  if (VT.isVector() && N0->hasOneUse() &&
       (!LegalTypes ||
        (!LegalOperations && VT.isInteger() && N0.getValueType().isInteger() &&
-        TLI.isTypeLegal(VT.getVectorElementType()))) &&
-      N0.getOpcode() == ISD::BUILD_VECTOR && N0->hasOneUse() &&
-      cast<BuildVectorSDNode>(N0)->isConstant())
-    return ConstantFoldBITCASTofBUILD_VECTOR(N0.getNode(),
-                                             VT.getVectorElementType());
+        TLI.isTypeLegal(VT.getVectorElementType())))) {
+    if (N0.getOpcode() == ISD::BUILD_VECTOR &&
+        cast<BuildVectorSDNode>(N0)->isConstant())
+      return ConstantFoldBITCASTofBUILD_VECTOR(N0.getNode(),
+                                               VT.getVectorElementType());
+
+    // In the case of SPLAT_VECTOR, convert it back to a BUILD_VECTOR first and
+    // fold it that way
+    if (N0.getOpcode() == ISD::SPLAT_VECTOR &&
+        DAG.isConstantValueOfAnyType(N0.getOperand(0))) {
+
+      auto BVN = DAG.getSplatBuildVector(N0.getValueType(), SDLoc(N0),
+                                         N0.getOperand(0));
+      return ConstantFoldBITCASTofBUILD_VECTOR(BVN.getNode(),
+                                               VT.getVectorElementType());
+    }
+  }
 
   // If the input is a constant, let getNode fold it.
   if (isIntOrFPConstant(N0)) {
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -3030,6 +3030,14 @@
     }
     break;
   }
+  case ISD::SPLAT_VECTOR: {
+    SDValue Scl = Op.getOperand(0);
+    if (Scl.isUndef())
+      KnownUndef.setAllBits();
+    if (isNullConstant(Scl) || isNullFPConstant(Scl))
+      KnownZero.setAllBits();
+    break;
+  }
   case ISD::CONCAT_VECTORS: {
     EVT SubVT = Op.getOperand(0).getValueType();
     unsigned NumSubVecs = Op.getNumOperands();
diff --git a/llvm/test/CodeGen/WebAssembly/pr59626.ll b/llvm/test/CodeGen/WebAssembly/pr59626.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/pr59626.ll
@@ -0,0 +1,30 @@
+; RUN: llc < %s -mtriple=wasm64-- -mattr=+simd128 | FileCheck %s
+
+define i8 @f(ptr %0, ptr %1) {
+; CHECK-LABEL: f:
+; CHECK:         .functype f (i64, i64) -> (i32)
+; CHECK-NEXT:    .local i32
+; CHECK-NEXT:  # %bb.0: # %BB
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    i32.const 0
+; CHECK-NEXT:    i32.store8 2
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    i32.const 0
+; CHECK-NEXT:    i32.store16 0
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    i8x16.splat
+; CHECK-NEXT:    v128.store16_lane 0, 0
+; CHECK-NEXT:    drop
+; CHECK-NEXT:    i32.const 0
+; CHECK-NEXT:    # fallthrough-return
+BB:
+  store <3 x i8> zeroinitializer, ptr %0
+  %S = shufflevector <3 x i128> zeroinitializer, <3 x i128> <i128 0, i128 1, i128 2>, <3 x i32> undef
+  %C = icmp ule <3 x i128> %S, zeroinitializer
+  %C1 = zext <3 x i1> %C to <3 x i8>
+  %E = extractelement <3 x i8> %C1, i32 0
+  %B = sdiv <3 x i8> <i8 1, i8 3, i8 5>, %C1
+  store <3 x i8> %B, ptr %1
+  ret i8 %E
+}