Index: lib/Target/SystemZ/SystemZISelLowering.cpp
===================================================================
--- lib/Target/SystemZ/SystemZISelLowering.cpp
+++ lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -1844,11 +1844,14 @@
                               ISD::SEXTLOAD :
                               ISD::ZEXTLOAD);
   if (C.Op0.getValueType() != MVT::i32 ||
-      Load->getExtensionType() != ExtType)
+      Load->getExtensionType() != ExtType) {
     C.Op0 = DAG.getExtLoad(ExtType, SDLoc(Load), MVT::i32, Load->getChain(),
                            Load->getBasePtr(), Load->getPointerInfo(),
                            Load->getMemoryVT(), Load->getAlignment(),
                            Load->getMemOperand()->getFlags());
+    // Update the chain uses.
+    DAG.ReplaceAllUsesOfValueWith(SDValue(Load, 1), C.Op0.getValue(1));
+  }
 
   // Make sure that the second operand is an i32 with the right value.
   if (C.Op1.getValueType() != MVT::i32 ||
@@ -2940,9 +2943,13 @@
   // but we need this case for bitcasts that are created during lowering
   // and which are then lowered themselves.
   if (auto *LoadN = dyn_cast<LoadSDNode>(In))
-    if (ISD::isNormalLoad(LoadN))
-      return DAG.getLoad(ResVT, DL, LoadN->getChain(), LoadN->getBasePtr(),
-                         LoadN->getMemOperand());
+    if (ISD::isNormalLoad(LoadN)) {
+      SDValue NewLoad = DAG.getLoad(ResVT, DL, LoadN->getChain(),
+                                    LoadN->getBasePtr(), LoadN->getMemOperand());
+      // Update the chain uses.
+      DAG.ReplaceAllUsesOfValueWith(SDValue(LoadN, 1), NewLoad.getValue(1));
+      return NewLoad;
+    }
 
   if (InVT == MVT::i32 && ResVT == MVT::f32) {
     SDValue In64;
Index: test/CodeGen/SystemZ/dag-combine-02.ll
===================================================================
--- /dev/null
+++ test/CodeGen/SystemZ/dag-combine-02.ll
@@ -0,0 +1,192 @@
+; Test that adjustSubwordCmp() maintains the chains properly when creating a
+; new extending load.
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z13 -O3 | FileCheck %s
+
+@g_56 = external hidden unnamed_addr global i64, align 8
+@func_22.l_91 = external hidden unnamed_addr constant [4 x [7 x i16*]], align 8
+@g_102 = external hidden unnamed_addr global i16**, align 8
+@.str = external hidden unnamed_addr constant [2 x i8], align 2
+@.str.1 = external hidden unnamed_addr constant [15 x i8], align 2
+@crc32_context = external hidden unnamed_addr global i32, align 4
+@crc32_tab = external hidden unnamed_addr global [256 x i32], align 4
+@.str.2 = external hidden unnamed_addr constant [36 x i8], align 2
+@.str.3 = external hidden unnamed_addr constant [15 x i8], align 2
+@g_181.0.4.5 = external hidden unnamed_addr global i1, align 2
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #0
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1) #0
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #0
+
+; Function Attrs: nounwind
+define signext i32 @main(i32 signext, i8** nocapture readonly) local_unnamed_addr #1 {
+  %3 = alloca [4 x [7 x i16*]], align 8
+  %4 = icmp eq i32 %0, 2
+  br i1 %4, label %5, label %11
+
+; <label>:5:                                      ; preds = %2
+  %6 = getelementptr inbounds i8*, i8** %1, i64 1
+  %7 = load i8*, i8** %6, align 8
+  %8 = tail call signext i32 @strcmp(i8* %7, i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0)) #4
+  %9 = icmp eq i32 %8, 0
+  %10 = zext i1 %9 to i32
+  br label %11
+
+; <label>:11:                                     ; preds = %5, %2
+  %12 = phi i32 [ 0, %2 ], [ %10, %5 ]
+  br label %13
+
+; <label>:13:                                     ; preds = %13, %11
+  %14 = phi i64 [ 0, %11 ], [ %58, %13 ]
+  %15 = phi <4 x i32> [ <i32 0, i32 1, i32 2, i32 3>, %11 ], [ %59, %13 ]
+  %16 = and <4 x i32> %15, <i32 1, i32 1, i32 1, i32 1>
+  %17 = icmp eq <4 x i32> %16, zeroinitializer
+  %18 = lshr <4 x i32> %15, <i32 1, i32 1, i32 1, i32 1>
+  %19 = xor <4 x i32> %18, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %20 = select <4 x i1> %17, <4 x i32> %18, <4 x i32> %19
+  %21 = and <4 x i32> %20, <i32 1, i32 1, i32 1, i32 1>
+  %22 = icmp eq <4 x i32> %21, zeroinitializer
+  %23 = lshr <4 x i32> %20, <i32 1, i32 1, i32 1, i32 1>
+  %24 = xor <4 x i32> %23, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %25 = select <4 x i1> %22, <4 x i32> %23, <4 x i32> %24
+  %26 = and <4 x i32> %25, <i32 1, i32 1, i32 1, i32 1>
+  %27 = icmp eq <4 x i32> %26, zeroinitializer
+  %28 = lshr <4 x i32> %25, <i32 1, i32 1, i32 1, i32 1>
+  %29 = xor <4 x i32> %28, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %30 = select <4 x i1> %27, <4 x i32> %28, <4 x i32> %29
+  %31 = and <4 x i32> %30, <i32 1, i32 1, i32 1, i32 1>
+  %32 = icmp eq <4 x i32> %31, zeroinitializer
+  %33 = lshr <4 x i32> %30, <i32 1, i32 1, i32 1, i32 1>
+  %34 = xor <4 x i32> %33, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %35 = select <4 x i1> %32, <4 x i32> %33, <4 x i32> %34
+  %36 = and <4 x i32> %35, <i32 1, i32 1, i32 1, i32 1>
+  %37 = icmp eq <4 x i32> %36, zeroinitializer
+  %38 = lshr <4 x i32> %35, <i32 1, i32 1, i32 1, i32 1>
+  %39 = xor <4 x i32> %38, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %40 = select <4 x i1> %37, <4 x i32> %38, <4 x i32> %39
+  %41 = and <4 x i32> %40, <i32 1, i32 1, i32 1, i32 1>
+  %42 = icmp eq <4 x i32> %41, zeroinitializer
+  %43 = lshr <4 x i32> %40, <i32 1, i32 1, i32 1, i32 1>
+  %44 = xor <4 x i32> %43, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %45 = select <4 x i1> %42, <4 x i32> %43, <4 x i32> %44
+  %46 = and <4 x i32> %45, <i32 1, i32 1, i32 1, i32 1>
+  %47 = icmp eq <4 x i32> %46, zeroinitializer
+  %48 = lshr <4 x i32> %45, <i32 1, i32 1, i32 1, i32 1>
+  %49 = xor <4 x i32> %48, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %50 = select <4 x i1> %47, <4 x i32> %48, <4 x i32> %49
+  %51 = and <4 x i32> %50, <i32 1, i32 1, i32 1, i32 1>
+  %52 = icmp eq <4 x i32> %51, zeroinitializer
+  %53 = lshr <4 x i32> %50, <i32 1, i32 1, i32 1, i32 1>
+  %54 = xor <4 x i32> %53, <i32 -306674912, i32 -306674912, i32 -306674912, i32 -306674912>
+  %55 = select <4 x i1> %52, <4 x i32> %53, <4 x i32> %54
+  %56 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %14
+  %57 = bitcast i32* %56 to <4 x i32>*
+  store <4 x i32> %55, <4 x i32>* %57, align 4
+  %58 = add i64 %14, 4
+  %59 = add <4 x i32> %15, <i32 4, i32 4, i32 4, i32 4>
+  %60 = icmp eq i64 %58, 256
+  br i1 %60, label %61, label %13
+
+; <label>:61:                                     ; preds = %13
+; CHECK-LABEL: BB#6:
+; CHECK: stgrl   %r1, g_56
+; CHECK: llhrl   %r1, g_56+6
+; CHECK: stgrl   %r2, g_56
+  store i64 0, i64* @g_56, align 8
+  %62 = bitcast [4 x [7 x i16*]]* %3 to i8*
+  call void @llvm.lifetime.start.p0i8(i64 224, i8* nonnull %62) #5
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %62, i8* bitcast ([4 x [7 x i16*]]* @func_22.l_91 to i8*), i64 224, i32 8, i1 false) #5
+  %63 = getelementptr inbounds [4 x [7 x i16*]], [4 x [7 x i16*]]* %3, i64 0, i64 0, i64 2
+  store i16** %63, i16*** @g_102, align 8
+  %64 = load i64, i64* @g_56, align 8
+  store i64 2, i64* @g_56, align 8
+  %65 = and i64 %64, 65535
+  %66 = icmp eq i64 %65, 0
+  br i1 %66, label %68, label %67
+
+; <label>:67:                                     ; preds = %61
+  store i1 true, i1* @g_181.0.4.5, align 2
+  br label %68
+
+; <label>:68:                                     ; preds = %67, %61
+  call void @llvm.lifetime.end.p0i8(i64 224, i8* nonnull %62) #5
+  %69 = load i1, i1* @g_181.0.4.5, align 2
+  %70 = select i1 %69, i32 0, i32 72
+  %71 = load i32, i32* @crc32_context, align 4
+  %72 = lshr i32 %71, 8
+  %73 = and i32 %71, 255
+  %74 = xor i32 %73, %70
+  %75 = zext i32 %74 to i64
+  %76 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %75
+  %77 = load i32, i32* %76, align 4
+  %78 = xor i32 %72, %77
+  %79 = lshr i32 %78, 8
+  %80 = and i32 %78, 255
+  %81 = zext i32 %80 to i64
+  %82 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %81
+  %83 = load i32, i32* %82, align 4
+  %84 = xor i32 %79, %83
+  %85 = lshr i32 %84, 8
+  %86 = and i32 %84, 255
+  %87 = zext i32 %86 to i64
+  %88 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %87
+  %89 = load i32, i32* %88, align 4
+  %90 = xor i32 %85, %89
+  %91 = lshr i32 %90, 8
+  %92 = and i32 %90, 255
+  %93 = zext i32 %92 to i64
+  %94 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %93
+  %95 = load i32, i32* %94, align 4
+  %96 = xor i32 %91, %95
+  %97 = lshr i32 %96, 8
+  %98 = and i32 %96, 255
+  %99 = zext i32 %98 to i64
+  %100 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %99
+  %101 = load i32, i32* %100, align 4
+  %102 = xor i32 %97, %101
+  %103 = lshr i32 %102, 8
+  %104 = and i32 %102, 255
+  %105 = zext i32 %104 to i64
+  %106 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %105
+  %107 = load i32, i32* %106, align 4
+  %108 = xor i32 %103, %107
+  %109 = lshr i32 %108, 8
+  %110 = and i32 %108, 255
+  %111 = zext i32 %110 to i64
+  %112 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %111
+  %113 = load i32, i32* %112, align 4
+  %114 = xor i32 %109, %113
+  %115 = lshr i32 %114, 8
+  %116 = and i32 %114, 255
+  %117 = zext i32 %116 to i64
+  %118 = getelementptr inbounds [256 x i32], [256 x i32]* @crc32_tab, i64 0, i64 %117
+  %119 = load i32, i32* %118, align 4
+  %120 = xor i32 %115, %119
+  store i32 %120, i32* @crc32_context, align 4
+  %121 = icmp eq i32 %12, 0
+  br i1 %121, label %127, label %122
+
+; <label>:122:                                    ; preds = %68
+  %123 = xor i32 %120, -1
+  %124 = zext i32 %123 to i64
+  %125 = call signext i32 (i8*, ...) @printf(i8* getelementptr inbounds ([36 x i8], [36 x i8]* @.str.2, i64 0, i64 0), i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.1, i64 0, i64 0), i64 %124) #5
+  %126 = load i32, i32* @crc32_context, align 4
+  br label %127
+
+; <label>:127:                                    ; preds = %122, %68
+  %128 = phi i32 [ %120, %68 ], [ %126, %122 ]
+  %129 = xor i32 %128, -1
+  %130 = call signext i32 (i8*, ...) @printf(i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.3, i64 0, i64 0), i32 zeroext %129) #5
+  ret i32 0
+}
+
+; Function Attrs: nounwind readonly
+declare signext i32 @strcmp(i8* nocapture, i8* nocapture) local_unnamed_addr #2
+
+; Function Attrs: nounwind
+declare signext i32 @printf(i8* nocapture readonly, ...) local_unnamed_addr #3