1; RUN: opt < %s -instcombine -S | FileCheck %s
2
3target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
4
5; CHECK-LABEL: @oppositesign
6; CHECK: add nsw i16 %a, %b
7define i16 @oppositesign(i16 %x, i16 %y) {
8; %a is negative, %b is positive
9  %a = or i16 %x, 32768
10  %b = and i16 %y, 32767
11  %c = add i16 %a, %b
12  ret i16 %c
13}
14
15define i16 @zero_sign_bit(i16 %a) {
16; CHECK-LABEL: @zero_sign_bit(
17; CHECK-NEXT: and
18; CHECK-NEXT: add nuw
19; CHECK-NEXT: ret
20  %1 = and i16 %a, 32767
21  %2 = add i16 %1, 512
22  ret i16 %2
23}
24
25define i16 @zero_sign_bit2(i16 %a, i16 %b) {
26; CHECK-LABEL: @zero_sign_bit2(
27; CHECK-NEXT: and
28; CHECK-NEXT: and
29; CHECK-NEXT: add nuw
30; CHECK-NEXT: ret
31  %1 = and i16 %a, 32767
32  %2 = and i16 %b, 32767
33  %3 = add i16 %1, %2
34  ret i16 %3
35}
36
37declare i16 @bounded(i16 %input);
38declare i32 @__gxx_personality_v0(...);
39!0 = !{i16 0, i16 32768} ; [0, 32767]
40!1 = !{i16 0, i16 32769} ; [0, 32768]
41
42define i16 @add_bounded_values(i16 %a, i16 %b) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
43; CHECK-LABEL: @add_bounded_values(
44entry:
45  %c = call i16 @bounded(i16 %a), !range !0
46  %d = invoke i16 @bounded(i16 %b) to label %cont unwind label %lpad, !range !0
47cont:
48; %c and %d are in [0, 32767]. Therefore, %c + %d doesn't unsigned overflow.
49  %e = add i16 %c, %d
50; CHECK: add nuw i16 %c, %d
51  ret i16 %e
52lpad:
53  %0 = landingpad { i8*, i32 }
54          filter [0 x i8*] zeroinitializer
55  ret i16 42
56}
57
58define i16 @add_bounded_values_2(i16 %a, i16 %b) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
59; CHECK-LABEL: @add_bounded_values_2(
60entry:
61  %c = call i16 @bounded(i16 %a), !range !1
62  %d = invoke i16 @bounded(i16 %b) to label %cont unwind label %lpad, !range !1
63cont:
64; Similar to add_bounded_values, but %c and %d are in [0, 32768]. Therefore,
65; %c + %d may unsigned overflow and we cannot add NUW.
66  %e = add i16 %c, %d
67; CHECK: add i16 %c, %d
68  ret i16 %e
69lpad:
70  %0 = landingpad { i8*, i32 }
71          filter [0 x i8*] zeroinitializer
72  ret i16 42
73}
74
75; CHECK-LABEL: @ripple_nsw1
76; CHECK: add nsw i16 %a, %b
77define i16 @ripple_nsw1(i16 %x, i16 %y) {
78; %a has at most one bit set
79  %a = and i16 %y, 1
80
81; %b has a 0 bit other than the sign bit
82  %b = and i16 %x, 49151
83
84  %c = add i16 %a, %b
85  ret i16 %c
86}
87
88; Like the previous test, but flip %a and %b
89; CHECK-LABEL: @ripple_nsw2
90; CHECK: add nsw i16 %b, %a
91define i16 @ripple_nsw2(i16 %x, i16 %y) {
92  %a = and i16 %y, 1
93  %b = and i16 %x, 49151
94  %c = add i16 %b, %a
95  ret i16 %c
96}
97
98; CHECK-LABEL: @ripple_nsw3
99; CHECK: add nsw i16 %a, %b
100define i16 @ripple_nsw3(i16 %x, i16 %y) {
101  %a = and i16 %y, 43691
102  %b = and i16 %x, 21843
103  %c = add i16 %a, %b
104  ret i16 %c
105}
106
107; Like the previous test, but flip %a and %b
108; CHECK-LABEL: @ripple_nsw4
109; CHECK: add nsw i16 %b, %a
110define i16 @ripple_nsw4(i16 %x, i16 %y) {
111  %a = and i16 %y, 43691
112  %b = and i16 %x, 21843
113  %c = add i16 %b, %a
114  ret i16 %c
115}
116
117; CHECK-LABEL: @ripple_nsw5
118; CHECK: add nsw i16 %a, %b
119define i16 @ripple_nsw5(i16 %x, i16 %y) {
120  %a = or i16 %y, 43691
121  %b = or i16 %x, 54613
122  %c = add i16 %a, %b
123  ret i16 %c
124}
125
126; Like the previous test, but flip %a and %b
127; CHECK-LABEL: @ripple_nsw6
128; CHECK: add nsw i16 %b, %a
129define i16 @ripple_nsw6(i16 %x, i16 %y) {
130  %a = or i16 %y, 43691
131  %b = or i16 %x, 54613
132  %c = add i16 %b, %a
133  ret i16 %c
134}
135
136; CHECK-LABEL: @ripple_no_nsw1
137; CHECK: add i32 %a, %x
138define i32 @ripple_no_nsw1(i32 %x, i32 %y) {
139; We know nothing about %x
140  %a = and i32 %y, 1
141  %b = add i32 %a, %x
142  ret i32 %b
143}
144
145; CHECK-LABEL: @ripple_no_nsw2
146; CHECK: add nuw i16 %a, %b
147define i16 @ripple_no_nsw2(i16 %x, i16 %y) {
148; %a has at most one bit set
149  %a = and i16 %y, 1
150
151; %b has a 0 bit, but it is the sign bit
152  %b = and i16 %x, 32767
153
154  %c = add i16 %a, %b
155  ret i16 %c
156}
157
158; CHECK-LABEL: @ripple_no_nsw3
159; CHECK: add i16 %a, %b
160define i16 @ripple_no_nsw3(i16 %x, i16 %y) {
161  %a = and i16 %y, 43691
162  %b = and i16 %x, 21845
163  %c = add i16 %a, %b
164  ret i16 %c
165}
166
167; Like the previous test, but flip %a and %b
168; CHECK-LABEL: @ripple_no_nsw4
169; CHECK: add i16 %b, %a
170define i16 @ripple_no_nsw4(i16 %x, i16 %y) {
171  %a = and i16 %y, 43691
172  %b = and i16 %x, 21845
173  %c = add i16 %b, %a
174  ret i16 %c
175}
176
177; CHECK-LABEL: @ripple_no_nsw5
178; CHECK: add i16 %a, %b
179define i16 @ripple_no_nsw5(i16 %x, i16 %y) {
180  %a = or i16 %y, 43689
181  %b = or i16 %x, 54613
182  %c = add i16 %a, %b
183  ret i16 %c
184}
185
186; Like the previous test, but flip %a and %b
187; CHECK-LABEL: @ripple_no_nsw6
188; CHECK: add i16 %b, %a
189define i16 @ripple_no_nsw6(i16 %x, i16 %y) {
190  %a = or i16 %y, 43689
191  %b = or i16 %x, 54613
192  %c = add i16 %b, %a
193  ret i16 %c
194}
195