1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
| ; RUN: opt < %s -instcombine -S | FileCheck %s
; Remove an icmp by using its operand in the subsequent logic directly.
define i8 @zext_or_icmp_icmp(i8 %a, i8 %b) {
%mask = and i8 %a, 1
%toBool1 = icmp eq i8 %mask, 0
%toBool2 = icmp eq i8 %b, 0
%bothCond = or i1 %toBool1, %toBool2
%zext = zext i1 %bothCond to i8
ret i8 %zext
; CHECK-LABEL: zext_or_icmp_icmp(
; CHECK-NEXT: %mask = and i8 %a, 1
; CHECK-NEXT: %toBool2 = icmp eq i8 %b, 0
; CHECK-NEXT: %toBool22 = zext i1 %toBool2 to i8
; CHECK-NEXT: %1 = xor i8 %mask, 1
; CHECK-NEXT: %zext = or i8 %1, %toBool22
; CHECK-NEXT: ret i8 %zext
}
; Here, widening the or from i1 to i32 and removing one of the icmps would
; widen an undef value (created by the out-of-range shift), increasing the
; range of valid values for the return, so we can't do it.
define i32 @dont_widen_undef() {
entry:
br label %block2
block1:
br label %block2
block2:
%m.011 = phi i32 [ 33, %entry ], [ 0, %block1 ]
%cmp.i = icmp ugt i32 %m.011, 1
%m.1.op = lshr i32 1, %m.011
%sext.mask = and i32 %m.1.op, 65535
%cmp115 = icmp ne i32 %sext.mask, 0
%cmp1 = or i1 %cmp.i, %cmp115
%conv2 = zext i1 %cmp1 to i32
ret i32 %conv2
; CHECK-LABEL: dont_widen_undef(
; CHECK: %m.011 = phi i32 [ 33, %entry ], [ 0, %block1 ]
; CHECK-NEXT: %cmp.i = icmp ugt i32 %m.011, 1
; CHECK-NEXT: %m.1.op = lshr i32 1, %m.011
; CHECK-NEXT: %sext.mask = and i32 %m.1.op, 65535
; CHECK-NEXT: %cmp115 = icmp ne i32 %sext.mask, 0
; CHECK-NEXT: %cmp1 = or i1 %cmp.i, %cmp115
; CHECK-NEXT: %conv2 = zext i1 %cmp1 to i32
; CHECK-NEXT: ret i32 %conv2
}
|