File: shift-shift.ll

package info (click to toggle)
llvm-toolchain-11 1%3A11.0.1-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 995,808 kB
  • sloc: cpp: 4,767,656; ansic: 760,916; asm: 477,436; python: 170,940; objc: 69,804; lisp: 29,914; sh: 23,855; f90: 18,173; pascal: 7,551; perl: 7,471; ml: 5,603; awk: 3,489; makefile: 2,573; xml: 915; cs: 573; fortran: 503; javascript: 452
file content (135 lines) | stat: -rw-r--r-- 3,450 bytes parent folder | download | duplicates (5)
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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s

; These would crash if we didn't check for a negative shift.

; https://llvm.org/bugs/show_bug.cgi?id=12967

define void @pr12967() {
; CHECK-LABEL: @pr12967(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    br label [[LOOP]]
;
entry:
  br label %loop

loop:
  %c = phi i32 [ %shl, %loop ], [ undef, %entry ]
  %shr = shl i32 %c, 7
  %shl = lshr i32 %shr, -2
  br label %loop
}

; https://llvm.org/bugs/show_bug.cgi?id=26760

define void @pr26760() {
; CHECK-LABEL: @pr26760(
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    br label [[LOOP]]
;
entry:
  br label %loop

loop:
  %c = phi i32 [ %shl, %loop ], [ undef, %entry ]
  %shr = lshr i32 %c, 7
  %shl = shl i32 %shr, -2
  br label %loop
}

; Converting the 2 shifts to SHL 6 without the AND is wrong.
; https://llvm.org/bugs/show_bug.cgi?id=8547

define i32 @pr8547(i32* %g) {
; CHECK-LABEL: @pr8547(
; CHECK-NEXT:  codeRepl:
; CHECK-NEXT:    br label [[FOR_COND:%.*]]
; CHECK:       for.cond:
; CHECK-NEXT:    [[STOREMERGE:%.*]] = phi i32 [ 0, [[CODEREPL:%.*]] ], [ 5, [[FOR_COND]] ]
; CHECK-NEXT:    store i32 [[STOREMERGE]], i32* [[G:%.*]], align 4
; CHECK-NEXT:    [[TMP0:%.*]] = shl nuw nsw i32 [[STOREMERGE]], 6
; CHECK-NEXT:    [[CONV2:%.*]] = and i32 [[TMP0]], 64
; CHECK-NEXT:    [[TOBOOL:%.*]] = icmp eq i32 [[CONV2]], 0
; CHECK-NEXT:    br i1 [[TOBOOL]], label [[FOR_COND]], label [[CODEREPL2:%.*]]
; CHECK:       codeRepl2:
; CHECK-NEXT:    ret i32 [[CONV2]]
;
codeRepl:
  br label %for.cond

for.cond:
  %storemerge = phi i32 [ 0, %codeRepl ], [ 5, %for.cond ]
  store i32 %storemerge, i32* %g, align 4
  %shl = shl i32 %storemerge, 30
  %conv2 = lshr i32 %shl, 24
  %tobool = icmp eq i32 %conv2, 0
  br i1 %tobool, label %for.cond, label %codeRepl2

codeRepl2:
  ret i32 %conv2
}

; Two same direction shifts that add up to more than the bitwidth should get
; folded to zero.

define i32 @shl_shl(i32 %A) {
; CHECK-LABEL: @shl_shl(
; CHECK-NEXT:    ret i32 0
;
  %B = shl i32 %A, 6
  %C = shl i32 %B, 28
  ret i32 %C
}

define <2 x i33> @shl_shl_splat_vec(<2 x i33> %A) {
; CHECK-LABEL: @shl_shl_splat_vec(
; CHECK-NEXT:    ret <2 x i33> zeroinitializer
;
  %B = shl <2 x i33> %A, <i33 5, i33 5>
  %C = shl <2 x i33> %B, <i33 28, i33 28>
  ret <2 x i33> %C
}

; FIXME

define <2 x i33> @shl_shl_vec(<2 x i33> %A) {
; CHECK-LABEL: @shl_shl_vec(
; CHECK-NEXT:    [[B:%.*]] = shl <2 x i33> [[A:%.*]], <i33 6, i33 5>
; CHECK-NEXT:    [[C:%.*]] = shl <2 x i33> [[B]], <i33 27, i33 28>
; CHECK-NEXT:    ret <2 x i33> [[C]]
;
  %B = shl <2 x i33> %A, <i33 6, i33 5>
  %C = shl <2 x i33> %B, <i33 27, i33 28>
  ret <2 x i33> %C
}

define i232 @lshr_lshr(i232 %A) {
; CHECK-LABEL: @lshr_lshr(
; CHECK-NEXT:    ret i232 0
;
  %B = lshr i232 %A, 231
  %C = lshr i232 %B, 1
  ret i232 %C
}

define <2 x i32> @lshr_lshr_splat_vec(<2 x i32> %A) {
; CHECK-LABEL: @lshr_lshr_splat_vec(
; CHECK-NEXT:    ret <2 x i32> zeroinitializer
;
  %B = lshr <2 x i32> %A, <i32 28, i32 28>
  %C = lshr <2 x i32> %B, <i32 4, i32 4>
  ret <2 x i32> %C
}

define <2 x i32> @lshr_lshr_vec(<2 x i32> %A) {
; CHECK-LABEL: @lshr_lshr_vec(
; CHECK-NEXT:    ret <2 x i32> zeroinitializer
;
  %B = lshr <2 x i32> %A, <i32 29, i32 28>
  %C = lshr <2 x i32> %B, <i32 4, i32 5>
  ret <2 x i32> %C
}