llvm-project/llvm/test/Transforms/RewriteStatepointsForGC/base-vector.ll

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; RUN: opt < %s -rewrite-statepoints-for-gc -S | FileCheck %s
define i64 addrspace(1)* @test(<2 x i64 addrspace(1)*> %vec, i32 %idx) gc "statepoint-example" {
; CHECK-LABEL: @test
; CHECK: extractelement
; CHECK: extractelement
; CHECK: statepoint
; CHECK: gc.relocate
; CHECK-DAG: ; (%base_ee, %base_ee)
; CHECK: gc.relocate
; CHECK-DAG: ; (%base_ee, %obj)
; Note that the second extractelement is actually redundant here. A correct output would
; be to reuse the existing obj as a base since it is actually a base pointer.
entry:
%obj = extractelement <2 x i64 addrspace(1)*> %vec, i32 %idx
call void @do_safepoint() [ "deopt"() ]
ret i64 addrspace(1)* %obj
}
define i64 addrspace(1)* @test2(<2 x i64 addrspace(1)*>* %ptr, i1 %cnd, i32 %idx1, i32 %idx2) gc "statepoint-example" {
; CHECK-LABEL: test2
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
%vec = phi <2 x i64 addrspace(1)*> [ %obja, %taken ], [ %objb, %untaken ]
br i1 %cnd, label %taken2, label %untaken2
taken2: ; preds = %merge
%obj0 = extractelement <2 x i64 addrspace(1)*> %vec, i32 %idx1
br label %merge2
untaken2: ; preds = %merge
%obj1 = extractelement <2 x i64 addrspace(1)*> %vec, i32 %idx2
br label %merge2
merge2: ; preds = %untaken2, %taken2
; CHECK-LABEL: merge2:
[RewriteStatepointsForGC] Reduce the number of new instructions for base pointers When computing base pointers, we introduce new instructions to propagate the base of existing instructions which might not be bases. However, the algorithm doesn't make any effort to recognize when the new instruction to be inserted is the same as an existing one already in the IR. Since this is happening immediately before rewriting, we don't really have a chance to fix it after the pass runs without teaching loop passes about statepoints. I'm really not thrilled with this patch. I've rewritten it 4 different ways now, but this is the best I've come up with. The case where the new instruction is just the original base defining value could be merged into the existing algorithm with some complexity. The problem is that we might have something like an extractelement from a phi of two vectors. It may be trivially obvious that the base of the 0th element is an existing instruction, but I can't see how to make the algorithm itself figure that out. Thus, I resort to the call to SimplifyInstruction instead. Note that we can only adjust the instructions we've inserted ourselves. The live sets are still being tracked in side structures at this point in the code. We can't easily muck with instructions which might be in them. Long term, I'm really thinking we need to materialize the live pointer sets explicitly in the IR somehow rather than using side structures to track them. Differential Revision: http://reviews.llvm.org/D12004 llvm-svn: 246133
2015-08-27 09:02:28 +08:00
; CHECK-NEXT: %obj = phi i64 addrspace(1)*
; CHECK-NEXT: statepoint
; CHECK: gc.relocate
[RewriteStatepointsForGC] Reduce the number of new instructions for base pointers When computing base pointers, we introduce new instructions to propagate the base of existing instructions which might not be bases. However, the algorithm doesn't make any effort to recognize when the new instruction to be inserted is the same as an existing one already in the IR. Since this is happening immediately before rewriting, we don't really have a chance to fix it after the pass runs without teaching loop passes about statepoints. I'm really not thrilled with this patch. I've rewritten it 4 different ways now, but this is the best I've come up with. The case where the new instruction is just the original base defining value could be merged into the existing algorithm with some complexity. The problem is that we might have something like an extractelement from a phi of two vectors. It may be trivially obvious that the base of the 0th element is an existing instruction, but I can't see how to make the algorithm itself figure that out. Thus, I resort to the call to SimplifyInstruction instead. Note that we can only adjust the instructions we've inserted ourselves. The live sets are still being tracked in side structures at this point in the code. We can't easily muck with instructions which might be in them. Long term, I'm really thinking we need to materialize the live pointer sets explicitly in the IR somehow rather than using side structures to track them. Differential Revision: http://reviews.llvm.org/D12004 llvm-svn: 246133
2015-08-27 09:02:28 +08:00
; CHECK-DAG: ; (%obj, %obj)
%obj = phi i64 addrspace(1)* [ %obj0, %taken2 ], [ %obj1, %untaken2 ]
call void @do_safepoint() [ "deopt"() ]
ret i64 addrspace(1)* %obj
}
define i64 addrspace(1)* @test3(i64 addrspace(1)* %ptr) gc "statepoint-example" {
; CHECK-LABEL: test3
; CHECK: insertelement
; CHECK: extractelement
; CHECK: statepoint
; CHECK: gc.relocate
; CHECK-DAG: (%obj, %obj)
entry:
%vec = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %ptr, i32 0
%obj = extractelement <2 x i64 addrspace(1)*> %vec, i32 0
call void @do_safepoint() [ "deopt"() ]
ret i64 addrspace(1)* %obj
}
define i64 addrspace(1)* @test4(i64 addrspace(1)* %ptr) gc "statepoint-example" {
; CHECK-LABEL: test4
; CHECK: statepoint
; CHECK: gc.relocate
; CHECK-DAG: ; (%ptr, %obj)
; CHECK: gc.relocate
; CHECK-DAG: ; (%ptr, %ptr)
; When we can optimize an extractelement from a known
; index and avoid introducing new base pointer instructions
entry:
%derived = getelementptr i64, i64 addrspace(1)* %ptr, i64 16
%veca = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %derived, i32 0
%vec = insertelement <2 x i64 addrspace(1)*> %veca, i64 addrspace(1)* %ptr, i32 1
%obj = extractelement <2 x i64 addrspace(1)*> %vec, i32 0
call void @do_safepoint() [ "deopt"() ]
ret i64 addrspace(1)* %obj
}
declare void @use(i64 addrspace(1)*) "gc-leaf-function"
define void @test5(i1 %cnd, i64 addrspace(1)* %obj) gc "statepoint-example" {
; CHECK-LABEL: @test5
; CHECK: gc.relocate
; CHECK-DAG: (%obj, %bdv)
; When we fundementally have to duplicate
entry:
%gep = getelementptr i64, i64 addrspace(1)* %obj, i64 1
%vec = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %gep, i32 0
%bdv = extractelement <2 x i64 addrspace(1)*> %vec, i32 0
call void @do_safepoint() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
call void @use(i64 addrspace(1)* %bdv)
ret void
}
define void @test6(i1 %cnd, i64 addrspace(1)* %obj, i64 %idx) gc "statepoint-example" {
; CHECK-LABEL: @test6
; CHECK: %gep = getelementptr i64, i64 addrspace(1)* %obj, i64 1
; CHECK: %vec.base = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %obj, i32 0, !is_base_value !0
; CHECK: %vec = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %gep, i32 0
; CHECK: %bdv.base = extractelement <2 x i64 addrspace(1)*> %vec.base, i64 %idx, !is_base_value !0
; CHECK: %bdv = extractelement <2 x i64 addrspace(1)*> %vec, i64 %idx
; CHECK: gc.statepoint
; CHECK: gc.relocate
; CHECK-DAG: (%bdv.base, %bdv)
; A more complicated example involving vector and scalar bases.
; This is derived from a failing test case when we didn't have correct
; insertelement handling.
entry:
%gep = getelementptr i64, i64 addrspace(1)* %obj, i64 1
%vec = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %gep, i32 0
%bdv = extractelement <2 x i64 addrspace(1)*> %vec, i64 %idx
call void @do_safepoint() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
call void @use(i64 addrspace(1)* %bdv)
ret void
}
define i64 addrspace(1)* @test7(i1 %cnd, i64 addrspace(1)* %obj, i64 addrspace(1)* %obj2) gc "statepoint-example" {
; CHECK-LABEL: @test7
entry:
%vec = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %obj2, i32 0
br label %merge1
merge1: ; preds = %merge1, %entry
; CHECK-LABEL: merge1:
; CHECK: vec2.base
; CHECK: vec2
; CHECK: gep
; CHECK: vec3.base
; CHECK: vec3
%vec2 = phi <2 x i64 addrspace(1)*> [ %vec, %entry ], [ %vec3, %merge1 ]
%gep = getelementptr i64, i64 addrspace(1)* %obj2, i64 1
%vec3 = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %gep, i32 0
br i1 %cnd, label %merge1, label %next1
next1: ; preds = %merge1
; CHECK-LABEL: next1:
; CHECK: bdv.base =
; CHECK: bdv =
%bdv = extractelement <2 x i64 addrspace(1)*> %vec2, i32 0
br label %merge
merge: ; preds = %merge, %next1
; CHECK-LABEL: merge:
; CHECK: %objb.base
; CHECK: %objb
; CHECK: gc.statepoint
; CHECK: gc.relocate
; CHECK-DAG: (%objb.base, %objb)
%objb = phi i64 addrspace(1)* [ %obj, %next1 ], [ %bdv, %merge ]
br i1 %cnd, label %merge, label %next
next: ; preds = %merge
call void @do_safepoint() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
ret i64 addrspace(1)* %objb
}
declare void @do_safepoint()