1 files changed, 68 insertions, 0 deletions
diff --git a/llvm/test/CodeGen/AMDGPU/kill-infinite-loop.ll b/llvm/test/CodeGen/AMDGPU/kill-infinite-loop.ll
new file mode 100644
index 00000000000..30280b967ad
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/kill-infinite-loop.ll
@@ -0,0 +1,68 @@
+; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -enable-var-scope %s
+; Although it's modeled without any control flow in order to get better code
+; out of the structurizer, @llvm.amdgcn.kill actually ends the thread that calls
+; it with "true". In case it's called in a provably infinite loop, we still
+; need to successfully exit and export something, even if we can't know where
+; to jump to in the LLVM IR. Therefore we insert a null export ourselves in
+; this case right before the s_endpgm to avoid GPU hangs, which is what this
+; tests.
+
+; CHECK-LABEL: return_void
+; Make sure that we remove the done bit from the original export
+; CHECK: exp mrt0 v{{[0-9]+}}, v{{[0-9]+}}, v{{[0-9]+}}, v{{[0-9]+}} vm
+; CHECK: exp null off, off, off, off done vm
+; CHECK-NEXT: s_endpgm
+define amdgpu_ps void @return_void(float %0) #0 {
+main_body:
+  %cmp = fcmp olt float %0, 1.000000e+01
+  br i1 %cmp, label %end, label %loop
+
+loop:
+  call void @llvm.amdgcn.kill(i1 false) #3
+  br label %loop
+
+end:
+  call void @llvm.amdgcn.exp.f32(i32 0, i32 15, float 0., float 0., float 0., float 1., i1 true, i1 true) #3
+  ret void
+}
+
+; Check that we also remove the done bit from compressed exports correctly.
+; CHECK-LABEL: return_void_compr
+; CHECK: exp mrt0 v{{[0-9]+}}, off, v{{[0-9]+}}, off compr vm
+; CHECK: exp null off, off, off, off done vm
+; CHECK-NEXT: s_endpgm
+define amdgpu_ps void @return_void_compr(float %0) #0 {
+main_body:
+  %cmp = fcmp olt float %0, 1.000000e+01
+  br i1 %cmp, label %end, label %loop
+
+loop:
+  call void @llvm.amdgcn.kill(i1 false) #3
+  br label %loop
+
+end:
+  call void @llvm.amdgcn.exp.compr.v2i16(i32 0, i32 5, <2 x i16> < i16 0, i16 0 >, <2 x i16> < i16 0, i16 0 >, i1 true, i1 true) #3
+  ret void
+}
+
+; In case there's an epilog, we shouldn't have to do this.
+; CHECK-LABEL: return_nonvoid
+; CHECK-NOT: exp null off, off, off, off done vm
+define amdgpu_ps float @return_nonvoid(float %0) #0 {
+main_body:
+  %cmp = fcmp olt float %0, 1.000000e+01
+  br i1 %cmp, label %end, label %loop
+
+loop:
+  call void @llvm.amdgcn.kill(i1 false) #3
+  br label %loop
+
+end:
+  ret float 0.
+}
+
+declare void @llvm.amdgcn.kill(i1) #0
+declare void @llvm.amdgcn.exp.f32(i32 immarg, i32 immarg, float, float, float, float, i1 immarg, i1 immarg) #0
+declare void @llvm.amdgcn.exp.compr.v2i16(i32 immarg, i32 immarg, <2 x i16>, <2 x i16>, i1 immarg, i1 immarg) #0
+
+attributes #0 = { nounwind }