7aad220795
For a loop, a join block is a block that is reachable along multiple disjoint paths from the exiting block of a loop. If the exit condition of the loop is divergent, then such join blocks must also be marked divergent. This currently fails in some cases because not all join blocks are identified correctly. The workaround is to conservatively mark every join block of any branch (not necessarily the exiting block of a loop) as divergent. https://bugs.llvm.org/show_bug.cgi?id=46372 Reviewed By: simoll Differential Revision: https://reviews.llvm.org/D81806
37 lines
1.2 KiB
LLVM
37 lines
1.2 KiB
LLVM
; RUN: opt -mtriple amdgcn-unknown-amdhsa -analyze -divergence -use-gpu-divergence-analysis %s | FileCheck %s
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; CHECK: bb3:
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; CHECK: DIVERGENT: %Guard.bb4 = phi i1 [ true, %bb1 ], [ false, %bb2 ]
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; CHECK: DIVERGENT: br i1 %Guard.bb4, label %bb4, label %bb5
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; Function Attrs: nounwind readnone speculatable
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declare i32 @llvm.amdgcn.workitem.id.x() #0
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define protected amdgpu_kernel void @test() {
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bb0:
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%tid.x = call i32 @llvm.amdgcn.workitem.id.x()
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%i5 = icmp eq i32 %tid.x, -1
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br label %bb1
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bb1: ; preds = %bb2, %bb0
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%lsr.iv = phi i32 [ 7, %bb0 ], [ %lsr.iv.next, %bb2 ]
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br i1 %i5, label %bb2, label %bb3
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bb2: ; preds = %bb1
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%lsr.iv.next = add nsw i32 %lsr.iv, -1
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%i14 = icmp eq i32 %lsr.iv.next, 0
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br i1 %i14, label %bb3, label %bb1
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bb3: ; preds = %bb2, %bb1
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%Guard.bb4 = phi i1 [ true, %bb1 ], [ false, %bb2 ]
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br i1 %Guard.bb4, label %bb4, label %bb5
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bb4: ; preds = %bb3
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br label %bb5
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bb5: ; preds = %bb3, %bb4
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ret void
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}
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attributes #0 = { nounwind readnone speculatable }
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