llvm/test/Transforms/RewriteStatepointsForGC/live-vector.ll
Philip Reames 33043ab317 [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




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246133 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-27 01:02:28 +00:00

153 lines
5.4 KiB
LLVM

; Test that we can correctly handle vectors of pointers in statepoint
; rewriting. Currently, we scalarize, but that's an implementation detail.
; RUN: opt %s -rewrite-statepoints-for-gc -S | FileCheck %s
; 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)* %obj.relocated.casted
entry:
%safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
ret i64 addrspace(1)* %obj
}
; A base vector from a argument
define <2 x i64 addrspace(1)*> @test2(<2 x i64 addrspace(1)*> %obj) gc "statepoint-example" {
; CHECK-LABEL: test2
; CHECK: extractelement
; CHECK-NEXT: extractelement
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: insertelement
; CHECK-NEXT: insertelement
; CHECK-NEXT: ret <2 x i64 addrspace(1)*> %7
entry:
%safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
ret <2 x i64 addrspace(1)*> %obj
}
; A base vector from 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: extractelement
; CHECK-NEXT: extractelement
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: insertelement
; CHECK-NEXT: insertelement
; CHECK-NEXT: ret <2 x i64 addrspace(1)*> %7
entry:
%obj = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
%safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
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: extractelement
; CHECK-NEXT: extractelement
; CHECK-NEXT: gc.statepoint
entry:
%obj = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
invoke i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
to label %normal_return unwind label %exceptional_return
; CHECK-LABEL: normal_return:
; CHECK: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: insertelement
; CHECK-NEXT: insertelement
; CHECK-NEXT: ret <2 x i64 addrspace(1)*> %8
normal_return: ; preds = %entry
ret <2 x i64 addrspace(1)*> %obj
; CHECK-LABEL: exceptional_return:
; CHECK: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: insertelement
; CHECK-NEXT: insertelement
; CHECK-NEXT: ret <2 x i64 addrspace(1)*> %14
exceptional_return: ; preds = %entry
%landing_pad4 = landingpad { i8*, i32 }
cleanup
ret <2 x i64 addrspace(1)*> %obj
}
; Can we handle an insert element with a constant offset? This effectively
; tests both the equal and inequal case since we have to relocate both indices
; in the vector.
define <2 x i64 addrspace(1)*> @test5(i64 addrspace(1)* %p)
gc "statepoint-example" {
; CHECK-LABEL: test5
; CHECK: insertelement
; CHECK-NEXT: extractelement
; CHECK-NEXT: extractelement
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: insertelement
; CHECK-NEXT: insertelement
; CHECK-NEXT: ret <2 x i64 addrspace(1)*> %7
entry:
%vec = insertelement <2 x i64 addrspace(1)*> undef, i64 addrspace(1)* %p, i32 0
%safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
ret <2 x i64 addrspace(1)*> %vec
}
; A base vector from a load
define <2 x i64 addrspace(1)*> @test6(i1 %cnd, <2 x i64 addrspace(1)*>* %ptr)
gc "statepoint-example" {
; CHECK-LABEL: test6
; CHECK-LABEL: merge:
; CHECK-NEXT: = phi
; CHECK-NEXT: extractelement
; CHECK-NEXT: extractelement
; CHECK-NEXT: gc.statepoint
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: gc.relocate
; CHECK-NEXT: bitcast
; CHECK-NEXT: insertelement
; CHECK-NEXT: insertelement
; CHECK-NEXT: ret <2 x i64 addrspace(1)*>
entry:
br i1 %cnd, label %taken, label %untaken
taken:
%obja = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
br label %merge
untaken:
%objb = load <2 x i64 addrspace(1)*>, <2 x i64 addrspace(1)*>* %ptr
br label %merge
merge:
%obj = phi <2 x i64 addrspace(1)*> [%obja, %taken], [%objb, %untaken]
%safepoint_token = call i32 (i64, i32, void ()*, i32, i32, ...) @llvm.experimental.gc.statepoint.p0f_isVoidf(i64 0, i32 0, void ()* @do_safepoint, i32 0, i32 0, i32 0, i32 0)
ret <2 x i64 addrspace(1)*> %obj
}
declare void @do_safepoint()
declare i32 @llvm.experimental.gc.statepoint.p0f_isVoidf(i64, i32, void ()*, i32, i32, ...)