diff --git a/llvm/test/Transforms/InstCombine/mul.ll b/llvm/test/Transforms/InstCombine/mul.ll
--- a/llvm/test/Transforms/InstCombine/mul.ll
+++ b/llvm/test/Transforms/InstCombine/mul.ll
@@ -607,3 +607,236 @@
   %mul = mul i32 %sel, %y
   ret i32 %mul
 }
+
+
+; TODO. 'select + mul' -> 'select + shl' for power of twos
+
+define i32 @shift_if_power2(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_power2(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 16, i32 4
+; CHECK-NEXT:    [[R:%.*]] = mul i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 16, i32 4
+  %r = mul i32 %sel, %x
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_nuw(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_power2_nuw(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 16, i32 4
+; CHECK-NEXT:    [[R:%.*]] = mul nuw i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 16, i32 4
+  %r = mul nuw i32 %sel, %x
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_nsw(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_power2_nsw(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 16, i32 4
+; CHECK-NEXT:    [[R:%.*]] = mul nsw i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 16, i32 4
+  %r = mul nsw i32 %sel, %x
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_nuw_nsw(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_power2_nuw_nsw(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 16, i32 4
+; CHECK-NEXT:    [[R:%.*]] = mul nuw nsw i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 16, i32 4
+  %r = mul nuw nsw i32 %sel, %x
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_nuw_nsw_min(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_power2_nuw_nsw_min(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 -2, i32 -2147483648
+; CHECK-NEXT:    [[R:%.*]] = mul nuw nsw i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 -2, i32 -2147483648
+  %r = mul nuw nsw i32 %sel, %x
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_double_select(i32 %x, i32 %y, i1 %cond1, i1 %cond2) {
+; CHECK-LABEL: @shift_if_power2_double_select(
+; CHECK-NEXT:    [[SHL_RES:%.*]] = shl i32 8, [[Y:%.*]]
+; CHECK-NEXT:    [[SEL1:%.*]] = select i1 [[COND1:%.*]], i32 [[SHL_RES]], i32 1024
+; CHECK-NEXT:    [[SEL2:%.*]] = select i1 [[COND2:%.*]], i32 16, i32 [[SEL1]]
+; CHECK-NEXT:    [[R:%.*]] = mul nuw i32 [[SEL2]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shl.res = shl i32 8, %y
+  %sel1 = select i1 %cond1, i32 %shl.res, i32 1024
+  %sel2 = select i1 %cond2, i32 16, i32 %sel1
+  %r = mul nuw i32 %x, %sel2
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_double_select_zext(i32 %x, i16 %y, i1 %cond1, i1 %cond2) {
+; CHECK-LABEL: @shift_if_power2_double_select_zext(
+; CHECK-NEXT:    [[SHL_RES:%.*]] = shl nsw i16 8, [[Y:%.*]]
+; CHECK-NEXT:    [[SHL:%.*]] = zext i16 [[SHL_RES]] to i32
+; CHECK-NEXT:    [[SEL1:%.*]] = select i1 [[COND1:%.*]], i32 [[SHL]], i32 1024
+; CHECK-NEXT:    [[SEL2:%.*]] = select i1 [[COND2:%.*]], i32 16, i32 [[SEL1]]
+; CHECK-NEXT:    [[R:%.*]] = mul nuw i32 [[SEL2]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shl.res = shl nsw i16 8, %y
+  %shl = zext i16 %shl.res to i32
+  %sel1 = select i1 %cond1, i32 %shl, i32 1024
+  %sel2 = select i1 %cond2, i32 16, i32 %sel1
+  %r = mul nuw i32 %x, %sel2
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_double_select_zext_mul_nsw(i32 %x, i16 %y, i1 %cond1, i1 %cond2) {
+; CHECK-LABEL: @shift_if_power2_double_select_zext_mul_nsw(
+; CHECK-NEXT:    [[SHL_RES:%.*]] = shl i16 8, [[Y:%.*]]
+; CHECK-NEXT:    [[SHL:%.*]] = zext i16 [[SHL_RES]] to i32
+; CHECK-NEXT:    [[SEL1:%.*]] = select i1 [[COND1:%.*]], i32 [[SHL]], i32 1024
+; CHECK-NEXT:    [[SEL2:%.*]] = select i1 [[COND2:%.*]], i32 16, i32 [[SEL1]]
+; CHECK-NEXT:    [[R:%.*]] = mul nsw i32 [[SEL2]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shl.res = shl i16 8, %y
+  %shl = zext i16 %shl.res to i32
+  %sel1 = select i1 %cond1, i32 %shl, i32 1024
+  %sel2 = select i1 %cond2, i32 16, i32 %sel1
+  %r = mul nsw i32 %x, %sel2
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_double_select_zext_shift_nsw(i32 %x, i16 %y, i1 %cond1, i1 %cond2) {
+; CHECK-LABEL: @shift_if_power2_double_select_zext_shift_nsw(
+; CHECK-NEXT:    [[SHL_RES:%.*]] = shl nsw i16 8, [[Y:%.*]]
+; CHECK-NEXT:    [[SHL:%.*]] = zext i16 [[SHL_RES]] to i32
+; CHECK-NEXT:    [[SEL1:%.*]] = select i1 [[COND1:%.*]], i32 [[SHL]], i32 1024
+; CHECK-NEXT:    [[SEL2:%.*]] = select i1 [[COND2:%.*]], i32 16, i32 [[SEL1]]
+; CHECK-NEXT:    [[R:%.*]] = mul nuw nsw i32 [[SEL2]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shl.res = shl nsw i16 8, %y
+  %shl = zext i16 %shl.res to i32
+  %sel1 = select i1 %cond1, i32 %shl, i32 1024
+  %sel2 = select i1 %cond2, i32 16, i32 %sel1
+  %r = mul nuw nsw i32 %x, %sel2
+  ret i32 %r
+}
+
+define i32 @shift_if_power2_zero(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_power2_zero(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 1, i32 4
+; CHECK-NEXT:    [[R:%.*]] = mul i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 1, i32 4
+  %r = mul i32 %sel, %x
+  ret i32 %r
+}
+
+define <2 x i8> @shift_if_power2_vector(<2 x i8> %px, i1 %cond) {
+; CHECK-LABEL: @shift_if_power2_vector(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], <2 x i8> <i8 16, i8 4>, <2 x i8> <i8 1, i8 32>
+; CHECK-NEXT:    [[R:%.*]] = mul <2 x i8> [[SEL]], [[PX:%.*]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %sel = select i1 %cond, <2 x i8> <i8 16, i8 4>, <2 x i8> <i8 1, i8 32>
+  %r = mul <2 x i8> %px, %sel
+  ret <2 x i8> %r
+}
+
+define i32 @shift_if_extra_use(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_extra_use(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 4, i32 128
+; CHECK-NEXT:    call void @use32(i32 [[SEL]])
+; CHECK-NEXT:    [[R:%.*]] = mul i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 4, i32 128
+  call void @use32(i32 %sel)
+  %r = mul i32 %sel, %x
+  ret i32 %r
+}
+
+; Negative tests for power2
+
+define i32 @shift_if_one_not_power2(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shift_if_one_not_power2(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], i32 5, i32 4
+; CHECK-NEXT:    [[R:%.*]] = mul i32 [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %sel = select i1 %cond, i32 5, i32 4
+  %r = mul i32 %sel, %x
+  ret i32 %r
+}
+
+define i32 @shift_if_not_power2_double_select(i32 %x, i32 %y, i1 %cond1, i1 %cond2) {
+; CHECK-LABEL: @shift_if_not_power2_double_select(
+; CHECK-NEXT:    [[SHL_RES:%.*]] = shl i32 7, [[Y:%.*]]
+; CHECK-NEXT:    [[SEL1:%.*]] = select i1 [[COND1:%.*]], i32 [[SHL_RES]], i32 1024
+; CHECK-NEXT:    [[SEL2:%.*]] = select i1 [[COND2:%.*]], i32 16, i32 [[SEL1]]
+; CHECK-NEXT:    [[R:%.*]] = mul nuw i32 [[SEL2]], [[X:%.*]]
+; CHECK-NEXT:    ret i32 [[R]]
+;
+  %shl.res = shl i32 7, %y
+  %sel1 = select i1 %cond1, i32 %shl.res, i32 1024
+  %sel2 = select i1 %cond2, i32 16, i32 %sel1
+  %r = mul nuw i32 %x, %sel2
+  ret i32 %r
+}
+
+define <2 x i8> @shift_if_one_not_power2_vector(<2 x i8> %px, i1 %cond) {
+; CHECK-LABEL: @shift_if_one_not_power2_vector(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], <2 x i8> <i8 16, i8 4>, <2 x i8> <i8 0, i8 32>
+; CHECK-NEXT:    [[R:%.*]] = mul <2 x i8> [[SEL]], [[PX:%.*]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %sel = select i1 %cond, <2 x i8> <i8 16, i8 4>, <2 x i8> <i8 0, i8 32>
+  %r = mul <2 x i8> %px, %sel
+  ret <2 x i8> %r
+}
+
+; Undef select + mul tests
+
+define <2 x i8> @shift_if_undef_vector(<2 x i8> %px, i1 %cond) {
+; CHECK-LABEL: @shift_if_undef_vector(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], <2 x i8> <i8 16, i8 4>, <2 x i8> <i8 undef, i8 32>
+; CHECK-NEXT:    [[R:%.*]] = mul <2 x i8> [[SEL]], [[PX:%.*]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %sel = select i1 %cond, <2 x i8> <i8 16, i8 4>, <2 x i8> <i8 undef, i8 32>
+  %r = mul <2 x i8> %px, %sel
+  ret <2 x i8> %r
+}
+
+define <2 x i8> @shift_if_different_lanes_undef_vector(<2 x i8> %px, i1 %cond) {
+; CHECK-LABEL: @shift_if_different_lanes_undef_vector(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], <2 x i8> <i8 16, i8 undef>, <2 x i8> <i8 undef, i8 32>
+; CHECK-NEXT:    [[R:%.*]] = mul <2 x i8> [[SEL]], [[PX:%.*]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %sel = select i1 %cond, <2 x i8> <i8 16, i8 undef>, <2 x i8> <i8 undef, i8 32>
+  %r = mul <2 x i8> %px, %sel
+  ret <2 x i8> %r
+}
+
+define <2 x i8> @shift_if_same_lane_undef_vector(<2 x i8> %px, i1 %cond) {
+; CHECK-LABEL: @shift_if_same_lane_undef_vector(
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[COND:%.*]], <2 x i8> <i8 undef, i8 4>, <2 x i8> <i8 undef, i8 32>
+; CHECK-NEXT:    [[R:%.*]] = mul <2 x i8> [[SEL]], [[PX:%.*]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %sel = select i1 %cond, <2 x i8> <i8 undef, i8 4>, <2 x i8> <i8 undef, i8 32>
+  %r = mul <2 x i8> %px, %sel
+  ret <2 x i8> %r
+}