// X >>l undef -> undef
if (isa<UndefValue>(C2))
return C2;
+ // undef >>l 0 -> undef
+ if (match(C2, m_Zero()))
+ return C1;
// undef >>l X -> 0
return Constant::getNullValue(C1->getType());
case Instruction::AShr:
// X >>a undef -> undef
if (isa<UndefValue>(C2))
return C2;
+ // undef >>a 0 -> undef
+ if (match(C2, m_Zero()))
+ return C1;
// TODO: undef >>a X -> undef if the shift is exact
// undef >>a X -> 0
return Constant::getNullValue(C1->getType());
// X << undef -> undef
if (isa<UndefValue>(C2))
return C2;
+ // undef << 0 -> undef
+ if (match(C2, m_Zero()))
+ return C1;
// undef << X -> 0
return Constant::getNullValue(C1->getType());
}
%b = shl i32 undef, %a
ret i32 %b
}
+
+; CHECK-LABEL: @test32
+; CHECK: ret i32 undef
+define i32 @test32(i32 %a) {
+ %b = shl i32 undef, 0
+ ret i32 %b
+}
+
+; CHECK-LABEL: @test33
+; CHECK: ret i32 undef
+define i32 @test33(i32 %a) {
+ %b = ashr i32 undef, 0
+ ret i32 %b
+}
+
+; CHECK-LABEL: @test34
+; CHECK: ret i32 undef
+define i32 @test34(i32 %a) {
+ %b = lshr i32 undef, 0
+ ret i32 %b
+}