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
|
; RUN: llc -verify-machineinstrs -mtriple=powerpc-unknown-linux-gnu -mattr=+altivec < %s | FileCheck %s
;; This test ensures that MergeConsecutiveStores does not attempt to
;; merge stores or loads when doing so would result in unaligned
;; memory operations (unless the target supports those, e.g. X86).
;; This issue happen in other situations for other targets, but PPC
;; with Altivec extensions was chosen for the test because it does not
;; support unaligned access with AltiVec instructions. If the 4
;; load/stores get merged to an v4i32 vector type severely bad code
;; gets generated: it painstakingly copies the values to a temporary
;; location on the stack, with vector ops, in order to then use
;; integer ops to load from the temporary stack location and store to
;; the final location. Yuck!
%struct.X = type { i32, i32, i32, i32 }
@fx = common global %struct.X zeroinitializer, align 4
@fy = common global %struct.X zeroinitializer, align 4
;; In this test case, lvx and stvx instructions should NOT be
;; generated, as the alignment is not sufficient for it to be
;; worthwhile.
;; CHECK-LABEL: f:
;; CHECK: lwzu
;; CHECK-NEXT: lwz
;; CHECK-NEXT: lwz
;; CHECK-NEXT: lwz
;; CHECK-NEXT: stwu
;; CHECK-NEXT: stw
;; CHECK-NEXT: stw
;; CHECK-NEXT: stw
;; CHECK-NEXT: blr
define void @f() {
entry:
%0 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 0), align 4
%1 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 1), align 4
%2 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 2), align 4
%3 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 3), align 4
store i32 %0, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 0), align 4
store i32 %1, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 1), align 4
store i32 %2, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 2), align 4
store i32 %3, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 3), align 4
ret void
}
@gx = common global %struct.X zeroinitializer, align 16
@gy = common global %struct.X zeroinitializer, align 16
;; In this test, lvx and stvx instructions SHOULD be generated, as
;; the 16-byte alignment of the new load/store is acceptable.
;; CHECK-LABEL: g:
;; CHECK: lvx
;; CHECK: stvx
;; CHECK: blr
define void @g() {
entry:
%0 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 0), align 16
%1 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 1), align 4
%2 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 2), align 4
%3 = load i32, i32* getelementptr inbounds (%struct.X, %struct.X* @fx, i32 0, i32 3), align 4
store i32 %0, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 0), align 16
store i32 %1, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 1), align 4
store i32 %2, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 2), align 4
store i32 %3, i32* getelementptr inbounds (%struct.X, %struct.X* @fy, i32 0, i32 3), align 4
ret void
}
|
