1 ; RUN: opt -O3 -S < %s | FileCheck --check-prefix=CHECK-OPT %s
2 ; RUN: llc < %s | FileCheck --check-prefix=CHECK-LLC %s
3 ; These tests are targetted at making sure we don't retain information
4 ; about memory which contains potential gc references across a statepoint.
5 ; They're carefully written to only outlaw forwarding of references.
6 ; Depending on the collector, forwarding non-reference fields or
7 ; constant null references may be perfectly legal. (If unimplemented.)
8 ; The general structure of these tests is:
9 ; - learn a fact about memory (via an assume)
10 ; - cross a statepoint
11 ; - check the same fact about memory (which we no longer know)
13 target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
14 target triple = "x86_64-pc-linux-gnu"
16 ; If not at a statepoint, we could forward known memory values
18 declare void @func() readonly
20 ;; Forwarding the value of a pointer load is invalid since it may have
21 ;; changed at the safepoint. Forwarding a non-gc pointer value would
22 ;; be valid, but is not currently implemented.
23 define i1 @test_load_forward(i32 addrspace(1)* addrspace(1)* %p) gc "statepoint-example" {
25 %before = load i32 addrspace(1)*, i32 addrspace(1)* addrspace(1)* %p
26 %cmp1 = call i1 @f(i32 addrspace(1)* %before)
27 call void @llvm.assume(i1 %cmp1)
28 %safepoint_token = tail call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0, i32 addrspace(1)* addrspace(1)* %p)
29 %pnew = call i32 addrspace(1)* addrspace(1)* @llvm.experimental.gc.relocate.p1p1i32(i32 %safepoint_token, i32 7, i32 7)
30 %after = load i32 addrspace(1)*, i32 addrspace(1)* addrspace(1)* %pnew
31 %cmp2 = call i1 @f(i32 addrspace(1)* %after)
34 ; CHECK-OPT-LABEL: test_load_forward
35 ; CHECK-OPT: ret i1 %cmp2
36 ; CHECK-LLC-LABEL: test_load_forward
40 ;; Same as above, but forwarding from a store
41 define i1 @test_store_forward(i32 addrspace(1)* addrspace(1)* %p,
42 i32 addrspace(1)* %v) gc "statepoint-example" {
44 %cmp1 = call i1 @f(i32 addrspace(1)* %v)
45 call void @llvm.assume(i1 %cmp1)
46 store i32 addrspace(1)* %v, i32 addrspace(1)* addrspace(1)* %p
47 %safepoint_token = tail call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0, i32 addrspace(1)* addrspace(1)* %p)
48 %pnew = call i32 addrspace(1)* addrspace(1)* @llvm.experimental.gc.relocate.p1p1i32(i32 %safepoint_token, i32 7, i32 7)
49 %after = load i32 addrspace(1)*, i32 addrspace(1)* addrspace(1)* %pnew
50 %cmp2 = call i1 @f(i32 addrspace(1)* %after)
53 ; CHECK-OPT-LABEL: test_store_forward
54 ; CHECK-OPT: ret i1 %cmp2
55 ; CHECK-LLC-LABEL: test_store_forward
59 ; A predicate on the pointer which is not simply null, but whose value
60 ; would be known unchanged if the pointer value could be forwarded.
61 ; The implementation of such a function could inspect the integral value
62 ; of the pointer and is thus not safe to reuse after a statepoint.
63 declare i1 @f(i32 addrspace(1)* %v) readnone
65 ; This is a variant of the test_load_forward test which is intended to
66 ; highlight the fact that a gc pointer can be stored in part of the heap
67 ; that is not itself GC managed. The GC may have an external mechanism
68 ; to know about and update that value at a safepoint. Note that the
69 ; statepoint does not provide the collector with this root.
70 define i1 @test_load_forward_nongc_heap(i32 addrspace(1)** %p) gc "statepoint-example" {
72 %before = load i32 addrspace(1)*, i32 addrspace(1)** %p
73 %cmp1 = call i1 @f(i32 addrspace(1)* %before)
74 call void @llvm.assume(i1 %cmp1)
75 call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0)
76 %after = load i32 addrspace(1)*, i32 addrspace(1)** %p
77 %cmp2 = call i1 @f(i32 addrspace(1)* %after)
80 ; CHECK-OPT-LABEL: test_load_forward_nongc_heap
81 ; CHECK-OPT: ret i1 %cmp2
82 ; CHECK-LLC-LABEL: test_load_forward_nongc_heap
86 ;; Same as above, but forwarding from a store
87 define i1 @test_store_forward_nongc_heap(i32 addrspace(1)** %p,
88 i32 addrspace(1)* %v) gc "statepoint-example" {
90 %cmp1 = call i1 @f(i32 addrspace(1)* %v)
91 call void @llvm.assume(i1 %cmp1)
92 store i32 addrspace(1)* %v, i32 addrspace(1)** %p
93 call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @func, i32 0, i32 0, i32 0, i32 0)
94 %after = load i32 addrspace(1)*, i32 addrspace(1)** %p
95 %cmp2 = call i1 @f(i32 addrspace(1)* %after)
98 ; CHECK-OPT-LABEL: test_store_forward_nongc_heap
99 ; CHECK-OPT: ret i1 %cmp2
100 ; CHECK-LLC-LABEL: test_store_forward_nongc_heap
104 declare void @llvm.assume(i1)
105 declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)
106 declare i32 addrspace(1)* addrspace(1)* @llvm.experimental.gc.relocate.p1p1i32(i32, i32, i32) #3