[RewriteStatepointsForGC] All constant should have null base pointer
Currently we consider that each constant has itself as a base value. I.e "base(const) = const".
This introduces couple of problems when we are trying to avoid reporting constants in statepoint live sets:
1. When querying "base( phi(const1, const2) )" we will get "phi(const1, const2)" as a base pointer. Since
it's not a constant we will record it in a stack map. However on practice we don't want this to happen
(constant are never relocated).
2. base( phi(const, gc ptr) ) = phi( const, base(gc ptr) ). This particular case imposes challenge on our
runtime - we don't expect to see constant base pointers other than null. This problems can be avoided
by treating all constant as if they were derived from null pointer base. I.e in a first case we will
not include constant pointer in a stack map at all. In a second case we will get "phi(null, base(gc ptr))"
as a base pointer which is a lot more convenient.
Differential Revision: http://reviews.llvm.org/D20584
llvm-svn: 270993
diff --git a/llvm/test/Transforms/RewriteStatepointsForGC/constants.ll b/llvm/test/Transforms/RewriteStatepointsForGC/constants.ll
index 68d6fd1..0a16f38 100644
--- a/llvm/test/Transforms/RewriteStatepointsForGC/constants.ll
+++ b/llvm/test/Transforms/RewriteStatepointsForGC/constants.ll
@@ -117,3 +117,147 @@
call void @foo() [ "deopt"() ]
ret i8 addrspace(1)* %load_addr
}
+
+define i8 @test8(i8 addrspace(1)* %p) gc "statepoint-example" {
+; Checks that base( phi(gep null, oop) ) = phi(null, base(oop)) and that we
+; correctly relocate this value
+; CHECK-LABEL: @test8
+entry:
+ %is_null = icmp eq i8 addrspace(1)* %p, null
+ br i1 %is_null, label %null.crit-edge, label %not-null
+
+not-null:
+ %load_addr = getelementptr inbounds i8, i8 addrspace(1)* %p, i64 8
+ br label %join
+
+null.crit-edge:
+ %load_addr.const = getelementptr inbounds i8, i8 addrspace(1)* null, i64 8
+ br label %join
+
+join:
+ %addr = phi i8 addrspace(1)* [ %load_addr, %not-null ], [%load_addr.const, %null.crit-edge]
+ ; CHECK: %addr.base = phi i8 addrspace(1)*
+ ; CHECK-DAG: [ %p, %not-null ]
+ ; CHECK-DAG: [ null, %null.crit-edge ]
+ ; CHECK: gc.statepoint
+ call void @foo() [ "deopt"() ]
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%addr.base, %addr.base)
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%addr.base, %addr)
+ br i1 %is_null, label %early-exit, label %use
+
+early-exit:
+ ret i8 0
+
+use:
+ %res = load i8, i8 addrspace(1)* %addr, align 1
+ ret i8 %res
+}
+
+define i8 @test9(i8 addrspace(1)* %p) gc "statepoint-example" {
+; Checks that base( phi(inttoptr, oop) ) = phi(null, base(oop)) and that we
+; correctly relocate this value
+; CHECK-LABEL: @test9
+entry:
+ %is_null = icmp eq i8 addrspace(1)* %p, null
+ br i1 %is_null, label %null.crit-edge, label %not-null
+
+not-null:
+ %load_addr = getelementptr inbounds i8, i8 addrspace(1)* %p, i64 8
+ br label %join
+
+null.crit-edge:
+ br label %join
+
+join:
+ %addr = phi i8 addrspace(1)* [ %load_addr, %not-null ], [inttoptr (i64 8 to i8 addrspace(1)*), %null.crit-edge]
+ ; CHECK: %addr.base = phi i8 addrspace(1)*
+ ; CHECK-DAG: [ %p, %not-null ]
+ ; CHECK-DAG: [ null, %null.crit-edge ]
+ ; CHECK: gc.statepoint
+ call void @foo() [ "deopt"() ]
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%addr.base, %addr.base)
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%addr.base, %addr)
+ br i1 %is_null, label %early-exit, label %use
+
+early-exit:
+ ret i8 0
+
+use:
+ %res = load i8, i8 addrspace(1)* %addr, align 1
+ ret i8 %res
+}
+
+define i8 @test10(i8 addrspace(1)* %p) gc "statepoint-example" {
+; Checks that base( phi(const gep, oop) ) = phi(null, base(oop)) and that we
+; correctly relocate this value
+; CHECK-LABEL: @test10
+entry:
+ %is_null = icmp eq i8 addrspace(1)* %p, null
+ br i1 %is_null, label %null.crit-edge, label %not-null
+
+not-null:
+ %load_addr = getelementptr inbounds i8, i8 addrspace(1)* %p, i64 8
+ br label %join
+
+null.crit-edge:
+ br label %join
+
+join:
+ %addr = phi i8 addrspace(1)* [ %load_addr, %not-null ], [getelementptr (i8, i8 addrspace(1)* null, i64 8), %null.crit-edge]
+ ; CHECK: %addr.base = phi i8 addrspace(1)*
+ ; CHECK-DAG: [ %p, %not-null ]
+ ; CHECK-DAG: [ null, %null.crit-edge ]
+ ; CHECK: gc.statepoint
+ call void @foo() [ "deopt"() ]
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%addr.base, %addr.base)
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%addr.base, %addr)
+ br i1 %is_null, label %early-exit, label %use
+
+early-exit:
+ ret i8 0
+
+use:
+ %res = load i8, i8 addrspace(1)* %addr, align 1
+ ret i8 %res
+}
+
+define i32 addrspace(1)* @test11(i1 %c) gc "statepoint-example" {
+; CHECK-LABEL: @test11
+; Checks that base( select(const1, const2) ) == null and that we don't record
+; such value in the oop map
+entry:
+ %val = select i1 %c, i32 addrspace(1)* inttoptr (i64 8 to i32 addrspace(1)*), i32 addrspace(1)* inttoptr (i64 15 to i32 addrspace(1)*)
+ ; CHECK: gc.statepoint
+ ; CHECK-NOT: call {{.*}}gc.relocate
+ call void @foo() [ "deopt"() ]
+ ret i32 addrspace(1)* %val
+}
+
+
+define <2 x i32 addrspace(1)*> @test12(i1 %c) gc "statepoint-example" {
+; CHECK-LABEL: @test12
+; Same as test11 but with vectors
+entry:
+ %val = select i1 %c, <2 x i32 addrspace(1)*> <i32 addrspace(1)* inttoptr (i64 5 to i32 addrspace(1)*),
+ i32 addrspace(1)* inttoptr (i64 15 to i32 addrspace(1)*)>,
+ <2 x i32 addrspace(1)*> <i32 addrspace(1)* inttoptr (i64 30 to i32 addrspace(1)*),
+ i32 addrspace(1)* inttoptr (i64 60 to i32 addrspace(1)*)>
+ ; CHECK: gc.statepoint
+ ; CHECK-NOT: call {{.*}}gc.relocate
+ call void @foo() [ "deopt"() ]
+ ret <2 x i32 addrspace(1)*> %val
+}
+
+define <2 x i32 addrspace(1)*> @test13(i1 %c, <2 x i32 addrspace(1)*> %ptr) gc "statepoint-example" {
+; CHECK-LABEL: @test13
+; Similar to test8, test9 and test10 but with vectors
+entry:
+ %val = select i1 %c, <2 x i32 addrspace(1)*> %ptr,
+ <2 x i32 addrspace(1)*> <i32 addrspace(1)* inttoptr (i64 30 to i32 addrspace(1)*), i32 addrspace(1)* inttoptr (i64 60 to i32 addrspace(1)*)>
+ ; CHECK: %val.base = select i1 %c, <2 x i32 addrspace(1)*> %ptr, <2 x i32 addrspace(1)*> zeroinitializer, !is_base_value !0
+ ; CHECK: gc.statepoint
+ call void @foo() [ "deopt"() ]
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%val.base, %val.base)
+ ; CHECK-DAG: call {{.*}}gc.relocate{{.*}}(%val.base, %val)
+ ret <2 x i32 addrspace(1)*> %val
+}