llvm-project/llvm/test/Transforms/RewriteStatepointsForGC/live-vector-nosplit.ll

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[rs4gc] Optionally directly relocated vector of pointers This patch teaches rewrite-statepoints-for-gc to relocate vector-of-pointers directly rather than trying to split them. This builds on the recent lowering/IR changes to allow vector typed gc.relocates. The motivation for this is that we recently found a bug in the vector splitting code where depending on visit order, a vector might not be relocated at some safepoint. Specifically, the bug is that the splitting code wasn't updating the side tables (live vector) of other safepoints. As a result, a vector which was live at two safepoints might not be updated at one of them. However, if you happened to visit safepoints in post order over the dominator tree, everything worked correctly. Weirdly, it turns out that post order is actually an incredibly common order to visit instructions in in practice. Frustratingly, I have not managed to write a test case which actually hits this. I can only reproduce it in large IR files produced by actual applications. Rather than continue to make this code more complicated, we can remove all of the complexity by just representing the relocation of the entire vector natively in the IR. At the moment, the new functionality is hidden behind a flag. To use this code, you need to pass "-rs4gc-split-vector-values=0". Once I have a chance to stress test with this option and get feedback from other users, my plan is to flip the default and remove the original splitting code. I would just remove it now, but given the rareness of the bug, I figured it was better to leave it in place until the new approach has been stress tested. Differential Revision: http://reviews.llvm.org/D15982 llvm-svn: 257244
2016-01-09 09:31:13 +08:00
; Test that we can correctly handle vectors of pointers in statepoint
; rewriting.
; RUN: opt < %s -rewrite-statepoints-for-gc -S | FileCheck %s
; RUN: opt < %s -passes=rewrite-statepoints-for-gc -S | FileCheck %s
[rs4gc] Optionally directly relocated vector of pointers This patch teaches rewrite-statepoints-for-gc to relocate vector-of-pointers directly rather than trying to split them. This builds on the recent lowering/IR changes to allow vector typed gc.relocates. The motivation for this is that we recently found a bug in the vector splitting code where depending on visit order, a vector might not be relocated at some safepoint. Specifically, the bug is that the splitting code wasn't updating the side tables (live vector) of other safepoints. As a result, a vector which was live at two safepoints might not be updated at one of them. However, if you happened to visit safepoints in post order over the dominator tree, everything worked correctly. Weirdly, it turns out that post order is actually an incredibly common order to visit instructions in in practice. Frustratingly, I have not managed to write a test case which actually hits this. I can only reproduce it in large IR files produced by actual applications. Rather than continue to make this code more complicated, we can remove all of the complexity by just representing the relocation of the entire vector natively in the IR. At the moment, the new functionality is hidden behind a flag. To use this code, you need to pass "-rs4gc-split-vector-values=0". Once I have a chance to stress test with this option and get feedback from other users, my plan is to flip the default and remove the original splitting code. I would just remove it now, but given the rareness of the bug, I figured it was better to leave it in place until the new approach has been stress tested. Differential Revision: http://reviews.llvm.org/D15982 llvm-svn: 257244
2016-01-09 09:31:13 +08:00
; A non-vector relocation for comparison
define i64 addrspace(1)* @test(i64 addrspace(1)* %obj) gc "statepoint-example" {
; CHECK-LABEL: test
; CHECK: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: ret i64 addrspace(1)*
; A base vector from a argument
entry:
call void @do_safepoint() [ "deopt"() ]
ret i64 addrspace(1)* %obj
}
; A vector argument
define <2 x i64 addrspace(1)*> @test2(<2 x i64 addrspace(1)*> %obj) gc "statepoint-example" {
; CHECK-LABEL: test2
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: ret <2 x i64 addrspace(1)*>
call void @do_safepoint() [ "deopt"() ]
ret <2 x i64 addrspace(1)*> %obj
}
; A load
define <2 x i64 addrspace(1)*> @test3(<2 x i64 addrspace(1)*>* %ptr) gc "statepoint-example" {
; CHECK-LABEL: test3
; CHECK: load
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: ret <2 x i64 addrspace(1)*>
entry:
%obj = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
call void @do_safepoint() [ "deopt"() ]
ret <2 x i64 addrspace(1)*> %obj
}
declare i32 @fake_personality_function()
; When a statepoint is an invoke rather than a call
define <2 x i64 addrspace(1)*> @test4(<2 x i64 addrspace(1)*>* %ptr) gc "statepoint-example" personality i32 ()* @fake_personality_function {
; CHECK-LABEL: test4
; CHECK: load
; CHECK-NEXT: gc.statepoint
entry:
%obj = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
invoke void @do_safepoint() [ "deopt"() ]
to label %normal_return unwind label %exceptional_return
normal_return: ; preds = %entry
; CHECK-LABEL: normal_return:
; CHECK: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: ret <2 x i64 addrspace(1)*>
ret <2 x i64 addrspace(1)*> %obj
exceptional_return: ; preds = %entry
; CHECK-LABEL: exceptional_return:
; CHECK: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: ret <2 x i64 addrspace(1)*>
%landing_pad4 = landingpad token
cleanup
ret <2 x i64 addrspace(1)*> %obj
}
; A newly created vector
define <2 x i64 addrspace(1)*> @test5(i64 addrspace(1)* %p) gc "statepoint-example" {
; CHECK-LABEL: test5
; CHECK: insertelement
; CHECK-NEXT: insertelement
[rs4gc] Optionally directly relocated vector of pointers This patch teaches rewrite-statepoints-for-gc to relocate vector-of-pointers directly rather than trying to split them. This builds on the recent lowering/IR changes to allow vector typed gc.relocates. The motivation for this is that we recently found a bug in the vector splitting code where depending on visit order, a vector might not be relocated at some safepoint. Specifically, the bug is that the splitting code wasn't updating the side tables (live vector) of other safepoints. As a result, a vector which was live at two safepoints might not be updated at one of them. However, if you happened to visit safepoints in post order over the dominator tree, everything worked correctly. Weirdly, it turns out that post order is actually an incredibly common order to visit instructions in in practice. Frustratingly, I have not managed to write a test case which actually hits this. I can only reproduce it in large IR files produced by actual applications. Rather than continue to make this code more complicated, we can remove all of the complexity by just representing the relocation of the entire vector natively in the IR. At the moment, the new functionality is hidden behind a flag. To use this code, you need to pass "-rs4gc-split-vector-values=0". Once I have a chance to stress test with this option and get feedback from other users, my plan is to flip the default and remove the original splitting code. I would just remove it now, but given the rareness of the bug, I figured it was better to leave it in place until the new approach has been stress tested. Differential Revision: http://reviews.llvm.org/D15982 llvm-svn: 257244
2016-01-09 09:31:13 +08:00
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
[rs4gc] Optionally directly relocated vector of pointers This patch teaches rewrite-statepoints-for-gc to relocate vector-of-pointers directly rather than trying to split them. This builds on the recent lowering/IR changes to allow vector typed gc.relocates. The motivation for this is that we recently found a bug in the vector splitting code where depending on visit order, a vector might not be relocated at some safepoint. Specifically, the bug is that the splitting code wasn't updating the side tables (live vector) of other safepoints. As a result, a vector which was live at two safepoints might not be updated at one of them. However, if you happened to visit safepoints in post order over the dominator tree, everything worked correctly. Weirdly, it turns out that post order is actually an incredibly common order to visit instructions in in practice. Frustratingly, I have not managed to write a test case which actually hits this. I can only reproduce it in large IR files produced by actual applications. Rather than continue to make this code more complicated, we can remove all of the complexity by just representing the relocation of the entire vector natively in the IR. At the moment, the new functionality is hidden behind a flag. To use this code, you need to pass "-rs4gc-split-vector-values=0". Once I have a chance to stress test with this option and get feedback from other users, my plan is to flip the default and remove the original splitting code. I would just remove it now, but given the rareness of the bug, I figured it was better to leave it in place until the new approach has been stress tested. Differential Revision: http://reviews.llvm.org/D15982 llvm-svn: 257244
2016-01-09 09:31:13 +08:00
; CHECK-NEXT: ret <2 x i64 addrspace(1)*> %vec.relocated.casted
entry:
%vec = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %p, i32 0
call void @do_safepoint() [ "deopt"() ]
ret <2 x i64 addrspace(1)*> %vec
}
; A merge point
define <2 x i64 addrspace(1)*> @test6(i1 %cnd, <2 x i64 addrspace(1)*>* %ptr) gc "statepoint-example" {
; CHECK-LABEL: test6
entry:
br i1 %cnd, label %taken, label %untaken
taken: ; preds = %entry
%obja = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
br label %merge
untaken: ; preds = %entry
%objb = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
br label %merge
merge: ; preds = %untaken, %taken
; CHECK-LABEL: merge:
; CHECK-NEXT: = phi
; CHECK-NEXT: = phi
[rs4gc] Optionally directly relocated vector of pointers This patch teaches rewrite-statepoints-for-gc to relocate vector-of-pointers directly rather than trying to split them. This builds on the recent lowering/IR changes to allow vector typed gc.relocates. The motivation for this is that we recently found a bug in the vector splitting code where depending on visit order, a vector might not be relocated at some safepoint. Specifically, the bug is that the splitting code wasn't updating the side tables (live vector) of other safepoints. As a result, a vector which was live at two safepoints might not be updated at one of them. However, if you happened to visit safepoints in post order over the dominator tree, everything worked correctly. Weirdly, it turns out that post order is actually an incredibly common order to visit instructions in in practice. Frustratingly, I have not managed to write a test case which actually hits this. I can only reproduce it in large IR files produced by actual applications. Rather than continue to make this code more complicated, we can remove all of the complexity by just representing the relocation of the entire vector natively in the IR. At the moment, the new functionality is hidden behind a flag. To use this code, you need to pass "-rs4gc-split-vector-values=0". Once I have a chance to stress test with this option and get feedback from other users, my plan is to flip the default and remove the original splitting code. I would just remove it now, but given the rareness of the bug, I figured it was better to leave it in place until the new approach has been stress tested. Differential Revision: http://reviews.llvm.org/D15982 llvm-svn: 257244
2016-01-09 09:31:13 +08:00
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
[rs4gc] Optionally directly relocated vector of pointers This patch teaches rewrite-statepoints-for-gc to relocate vector-of-pointers directly rather than trying to split them. This builds on the recent lowering/IR changes to allow vector typed gc.relocates. The motivation for this is that we recently found a bug in the vector splitting code where depending on visit order, a vector might not be relocated at some safepoint. Specifically, the bug is that the splitting code wasn't updating the side tables (live vector) of other safepoints. As a result, a vector which was live at two safepoints might not be updated at one of them. However, if you happened to visit safepoints in post order over the dominator tree, everything worked correctly. Weirdly, it turns out that post order is actually an incredibly common order to visit instructions in in practice. Frustratingly, I have not managed to write a test case which actually hits this. I can only reproduce it in large IR files produced by actual applications. Rather than continue to make this code more complicated, we can remove all of the complexity by just representing the relocation of the entire vector natively in the IR. At the moment, the new functionality is hidden behind a flag. To use this code, you need to pass "-rs4gc-split-vector-values=0". Once I have a chance to stress test with this option and get feedback from other users, my plan is to flip the default and remove the original splitting code. I would just remove it now, but given the rareness of the bug, I figured it was better to leave it in place until the new approach has been stress tested. Differential Revision: http://reviews.llvm.org/D15982 llvm-svn: 257244
2016-01-09 09:31:13 +08:00
; CHECK-NEXT: ret <2 x i64 addrspace(1)*>
%obj = phi <2 x i64 addrspace(1)*> [ %obja, %taken ], [ %objb, %untaken ]
call void @do_safepoint() [ "deopt"() ]
ret <2 x i64 addrspace(1)*> %obj
}
declare void @do_safepoint()