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
|
; RUN: opt -passes=gvn -S < %s | FileCheck %s
;
; The Global Value Numbering pass (GVN) propagates boolean values
; that are constant in dominated basic blocks to all the uses
; in these basic blocks. However, we don't want the constant propagated
; into fake.use intrinsics since this would render the intrinsic useless
; with respect to keeping the variable live up until the fake.use.
; This test checks that we don't generate any fake.uses with constant 0.
;
; Reduced from the following test case, generated with clang -O2 -S -emit-llvm -fextend-variable-liveness test.c
;
; extern void func1();
; extern int bar();
; extern void baz(int);
;
; int foo(int i, float f, int *punused)
; {
; int j = 3*i;
; if (j > 0) {
; int m = bar(i);
; if (m) {
; char b = f;
; baz(b);
; if (b)
; goto lab;
; func1();
; }
; lab:
; func1();
; }
; return 1;
; }
;; GVN should propagate a constant value through to a regular call, but not to
;; a fake use, which should continue to track the original value.
; CHECK: %[[CONV_VAR:[a-zA-Z0-9]+]] = fptosi
; CHECK: call {{.+}} @bees(i8 0)
; CHECK: call {{.+}} @llvm.fake.use(i8 %[[CONV_VAR]])
define i32 @foo(float %f) optdebug {
%conv = fptosi float %f to i8
%tobool3 = icmp eq i8 %conv, 0
br i1 %tobool3, label %if.end, label %lab
if.end:
tail call void (...) @bees(i8 %conv)
tail call void (...) @llvm.fake.use(i8 %conv)
br label %lab
lab:
ret i32 1
}
declare i32 @bar(...)
declare void @baz(i32)
declare void @bees(i32)
declare void @func1(...)
|
