diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -241,9 +241,11 @@
   Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
   assert(Op0->getType() == Op1->getType());
 
-  // If the shift amount is a one-use `sext`, we can demote it to `zext`.
+  // If the shift amount is a `sext`, we can demote it to `zext`.
+  // We indeed don't check use-count here, shift-by-zext is considered much
+  // more friendly for any further analysis.
   Value *Y;
-  if (match(Op1, m_OneUse(m_SExt(m_Value(Y))))) {
+  if (match(Op1, m_SExt(m_Value(Y)))) {
     Value *NewExt = Builder.CreateZExt(Y, I.getType(), Op1->getName());
     return BinaryOperator::Create(I.getOpcode(), Op0, NewExt);
   }
diff --git a/llvm/test/Transforms/InstCombine/shift-by-signext.ll b/llvm/test/Transforms/InstCombine/shift-by-signext.ll
--- a/llvm/test/Transforms/InstCombine/shift-by-signext.ll
+++ b/llvm/test/Transforms/InstCombine/shift-by-signext.ll
@@ -69,13 +69,14 @@
 define i32 @t6_twoshifts(i32 %x, i8 %shamt) {
 ; CHECK-LABEL: @t6_twoshifts(
 ; CHECK-NEXT:  bb:
-; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext i8 [[SHAMT:%.*]] to i32
 ; CHECK-NEXT:    br label [[WORK:%.*]]
 ; CHECK:       work:
 ; CHECK-NEXT:    br label [[END:%.*]]
 ; CHECK:       end:
-; CHECK-NEXT:    [[N0:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE]]
-; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[N0]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    [[SHAMT_WIDE1:%.*]] = zext i8 [[SHAMT:%.*]] to i32
+; CHECK-NEXT:    [[N0:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE1]]
+; CHECK-NEXT:    [[SHAMT_WIDE2:%.*]] = zext i8 [[SHAMT]] to i32
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[N0]], [[SHAMT_WIDE2]]
 ; CHECK-NEXT:    ret i32 [[R]]
 ;
 bb:
@@ -141,7 +142,8 @@
 ; CHECK-LABEL: @n11_extrause(
 ; CHECK-NEXT:    [[SHAMT_WIDE:%.*]] = sext i8 [[SHAMT:%.*]] to i32
 ; CHECK-NEXT:    call void @use32(i32 [[SHAMT_WIDE]])
-; CHECK-NEXT:    [[R:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    [[SHAMT_WIDE1:%.*]] = zext i8 [[SHAMT]] to i32
+; CHECK-NEXT:    [[R:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE1]]
 ; CHECK-NEXT:    ret i32 [[R]]
 ;
   %shamt_wide = sext i8 %shamt to i32
@@ -156,8 +158,10 @@
 ; CHECK:       work:
 ; CHECK-NEXT:    br label [[END:%.*]]
 ; CHECK:       end:
-; CHECK-NEXT:    [[N0:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE]]
-; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[N0]], [[SHAMT_WIDE]]
+; CHECK-NEXT:    [[SHAMT_WIDE1:%.*]] = zext i8 [[SHAMT]] to i32
+; CHECK-NEXT:    [[N0:%.*]] = shl i32 [[X:%.*]], [[SHAMT_WIDE1]]
+; CHECK-NEXT:    [[SHAMT_WIDE2:%.*]] = zext i8 [[SHAMT]] to i32
+; CHECK-NEXT:    [[R:%.*]] = ashr i32 [[N0]], [[SHAMT_WIDE2]]
 ; CHECK-NEXT:    call void @use32(i32 [[SHAMT_WIDE]])
 ; CHECK-NEXT:    ret i32 [[R]]
 ;