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

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Revert "Temporarily Revert "Add basic loop fusion pass."" The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
2019-04-17 12:52:47 +08:00
; RUN: opt < %s -rewrite-statepoints-for-gc -S 2>&1 | FileCheck %s
; RUN: opt < %s -passes=rewrite-statepoints-for-gc -S 2>&1 | FileCheck %s
; The rewriting needs to make %obj loop variant by inserting a phi
; of the original value and it's relocation.
declare i64 addrspace(1)* @generate_obj() "gc-leaf-function"
declare void @use_obj(i64 addrspace(1)*) "gc-leaf-function"
define void @def_use_safepoint() gc "statepoint-example" {
; CHECK-LABEL: def_use_safepoint
; CHECK: phi i64 addrspace(1)*
; CHECK-DAG: [ %obj.relocated.casted, %loop ]
; CHECK-DAG: [ %obj, %entry ]
entry:
%obj = call i64 addrspace(1)* @generate_obj()
br label %loop
loop: ; preds = %loop, %entry
call void @use_obj(i64 addrspace(1)* %obj)
call void @do_safepoint() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
br label %loop
}
declare void @do_safepoint()
declare void @parse_point(i64 addrspace(1)*)
define i64 addrspace(1)* @test1(i32 %caller, i8 addrspace(1)* %a, i8 addrspace(1)* %b, i32 %unknown) gc "statepoint-example" {
; CHECK-LABEL: test1
entry:
br i1 undef, label %left, label %right
left: ; preds = %entry
; CHECK: left:
; CHECK-NEXT: %a.cast = bitcast i8 addrspace(1)* %a to i64 addrspace(1)*
; CHECK-NEXT: [[CAST_L:%.*]] = bitcast i8 addrspace(1)* %a to i64 addrspace(1)*
; Our safepoint placement pass calls removeUnreachableBlocks, which does a bunch
; of simplifications to branch instructions. This bug is visible only when
; there are multiple branches into the same block from the same predecessor, and
; the following ceremony is to make that artefact survive a call to
; removeUnreachableBlocks. As an example, "br i1 undef, label %merge, label %merge"
; will get simplified to "br label %merge" by removeUnreachableBlocks.
%a.cast = bitcast i8 addrspace(1)* %a to i64 addrspace(1)*
switch i32 %unknown, label %right [
i32 0, label %merge
i32 1, label %merge
i32 5, label %merge
i32 3, label %right
]
right: ; preds = %left, %left, %entry
; CHECK: right:
; CHECK-NEXT: %b.cast = bitcast i8 addrspace(1)* %b to i64 addrspace(1)*
; CHECK-NEXT: [[CAST_R:%.*]] = bitcast i8 addrspace(1)* %b to i64 addrspace(1)*
%b.cast = bitcast i8 addrspace(1)* %b to i64 addrspace(1)*
br label %merge
merge: ; preds = %right, %left, %left, %left
; CHECK: merge:
; CHECK-NEXT: %value.base = phi i64 addrspace(1)* [ [[CAST_L]], %left ], [ [[CAST_L]], %left ], [ [[CAST_L]], %left ], [ [[CAST_R]], %right ], !is_base_value !0
%value = phi i64 addrspace(1)* [ %a.cast, %left ], [ %a.cast, %left ], [ %a.cast, %left ], [ %b.cast, %right ]
call void @parse_point(i64 addrspace(1)* %value) [ "deopt"(i32 0, i32 0, i32 0, i32 0, i32 0) ]
ret i64 addrspace(1)* %value
}
;; The purpose of this test is to ensure that when two live values share a
;; base defining value with inherent conflicts, we end up with a *single*
;; base phi/select per such node. This is testing an optimization, not a
;; fundemental correctness criteria
define void @test2(i1 %cnd, i64 addrspace(1)* %base_obj, i64 addrspace(1)* %base_arg2) gc "statepoint-example" {
; CHECK-LABEL: @test2
entry:
%obj = getelementptr i64, i64 addrspace(1)* %base_obj, i32 1
br label %loop
; CHECK-LABEL: loop
; CHECK: %current.base = phi i64 addrspace(1)*
; CHECK-DAG: [ %base_obj, %entry ]
; Given the two selects are equivelent, so are their base phis - ideally,
; we'd have commoned these, but that's a missed optimization, not correctness.
; CHECK-DAG: [ [[DISCARD:%.*.base.relocated.casted]], %loop ]
; CHECK-NOT: extra.base
; CHECK: next.base = select
; CHECK: next = select
; CHECK: extra2.base = select
; CHECK: extra2 = select
; CHECK: statepoint
;; Both 'next' and 'extra2' are live across the backedge safepoint...
loop: ; preds = %loop, %entry
%current = phi i64 addrspace(1)* [ %obj, %entry ], [ %next, %loop ]
%extra = phi i64 addrspace(1)* [ %obj, %entry ], [ %extra2, %loop ]
%nexta = getelementptr i64, i64 addrspace(1)* %current, i32 1
%next = select i1 %cnd, i64 addrspace(1)* %nexta, i64 addrspace(1)* %base_arg2
%extra2 = select i1 %cnd, i64 addrspace(1)* %nexta, i64 addrspace(1)* %base_arg2
call void @foo() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
br label %loop
}
define i64 addrspace(1)* @test3(i1 %cnd, i64 addrspace(1)* %obj, i64 addrspace(1)* %obj2) gc "statepoint-example" {
; CHECK-LABEL: @test3
entry:
br i1 %cnd, label %merge, label %taken
taken: ; preds = %entry
br label %merge
merge: ; preds = %taken, %entry
; CHECK-LABEL: merge:
; CHECK-NEXT: phi
; CHECK-NEXT: phi
; CHECK-NEXT: gc.statepoint
%bdv = phi i64 addrspace(1)* [ %obj, %entry ], [ %obj2, %taken ]
call void @foo() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
ret i64 addrspace(1)* %bdv
}
define i64 addrspace(1)* @test4(i1 %cnd, i64 addrspace(1)* %obj, i64 addrspace(1)* %obj2) gc "statepoint-example" {
; CHECK-LABEL: @test4
entry:
br i1 %cnd, label %merge, label %taken
taken: ; preds = %entry
br label %merge
merge: ; preds = %taken, %entry
; CHECK-LABEL: merge:
; CHECK-NEXT: phi
; CHECK-NEXT: gc.statepoint
%bdv = phi i64 addrspace(1)* [ %obj, %entry ], [ %obj, %taken ]
call void @foo() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
ret i64 addrspace(1)* %bdv
}
define i64 addrspace(1)* @test5(i1 %cnd, i64 addrspace(1)* %obj, i64 addrspace(1)* %obj2) gc "statepoint-example" {
; CHECK-LABEL: @test5
entry:
br label %merge
merge: ; preds = %merge, %entry
; CHECK-LABEL: merge:
; CHECK-NEXT: phi
; CHECK-NEXT: phi
; CHECK-NEXT: br i1
%bdv = phi i64 addrspace(1)* [ %obj, %entry ], [ %obj2, %merge ]
br i1 %cnd, label %merge, label %next
next: ; preds = %merge
call void @foo() [ "deopt"(i32 0, i32 -1, i32 0, i32 0, i32 0) ]
ret i64 addrspace(1)* %bdv
}
[rs4gc] avoid insert base computation instructions for deopt uses If we have a value live over a call which is used for deopt at the call, we know that the value must be a base pointer. We can avoid potentially inserting IR to materialize a base for this value. In it's current form, this is mostly a compile time optimization. Building the base pointer graph (and then optimizing it away again) is a relatively expensive operation. We also sometimes end up with better codegen in practice - due to failures in optimizing away the inserted base pointer propogation - but those are optimization bugs we're fixing concurrently. The alternative to this would be to extend the base pointer inference with the ability to generally reuse multiple-base input instructions (phis and selects). That's somewhat invasive and complicated, so we're defering it a bit longer. Differential Revision: https://reviews.llvm.org/D97885
2021-03-06 01:55:36 +08:00
; We know from the deopt use that %bdv must be a base value, and as
; result can avoid materializing the extra copy of the BDV phi node.
; (Even without a general forward analysis)
define i64 addrspace(1)* @test6(i1 %cnd, i64 addrspace(1)* %obj, i64 addrspace(1)* %obj2) gc "statepoint-example" {
; CHECK-LABEL: @test6
entry:
br label %merge
merge: ; preds = %merge, %entry
; CHECK-LABEL: merge:
; CHECK-NEXT: phi
; CHECK-NEXT: br i1
%bdv = phi i64 addrspace(1)* [ %obj, %entry ], [ %obj2, %merge ]
br i1 %cnd, label %merge, label %next
next: ; preds = %merge
call void @foo() [ "deopt"(i64 addrspace(1)* %bdv) ]
ret i64 addrspace(1)* %bdv
}
Revert "Temporarily Revert "Add basic loop fusion pass."" The reversion apparently deleted the test/Transforms directory. Will be re-reverting again. llvm-svn: 358552
2019-04-17 12:52:47 +08:00
declare void @foo()