d61aac76bf
If we assume SPMD-mode during the fixpoint iteration we have to execute the kernel in SPMD-mode. If we change our mind during manifest there is the chance of a mismatch between the simplification, e.g., of `__kmpc_is_spmd_exec_mode` calls, and the execution mode. This problem was introduced in D109438. This patch is compromise to resolve the problem purely in OpenMP-opt while trying to keep the benefits of D109438 around. This might not always work, see `get_hardware_num_threads_in_block_fold` but it often does. At the same time we do keep value specialization and execution mode in sync. Proper solutions to this problem should be considered. I believe a new execution mode is the easiest way forward (Singleton-SPMD). Alternatively, SPMD-mode execution can be used with a way to provide a new thread_limit (here 1) to the runtime. This is more general and could be useful if we see `num_threads` clauses or workshared loops with small trip counts in the kernel. In either proposal we need to disable the guarding for the kernel (which was the motivation for D109438). Reviewed By: jhuber6 Differential Revision: https://reviews.llvm.org/D112894
80 lines
3.5 KiB
LLVM
80 lines
3.5 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-attributes
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; RUN: opt < %s -S -passes=openmp-opt -openmp-opt-inline-device | FileCheck %s
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%struct.ident_t = type { i32, i32, i32, i32, i8* }
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@0 = private unnamed_addr constant [23 x i8] c";unknown;unknown;0;0;;\00", align 1
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@1 = private unnamed_addr constant %struct.ident_t { i32 0, i32 2, i32 0, i32 0, i8* getelementptr inbounds ([23 x i8], [23 x i8]* @0, i32 0, i32 0) }, align 8
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@__omp_offloading_fd02_c0934fc2_foo_l4_exec_mode = weak constant i8 1
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@llvm.compiler.used = appending global [1 x i8*] [i8* @__omp_offloading_fd02_c0934fc2_foo_l4_exec_mode], section "llvm.metadata"
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@G = external global i8
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; Function Attrs: convergent norecurse nounwind
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define weak void @__omp_offloading_fd02_c0934fc2_foo_l4() #0 {
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; CHECK: Function Attrs: convergent norecurse nounwind
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; CHECK-LABEL: @__omp_offloading_fd02_c0934fc2_foo_l4(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[TMP0:%.*]] = call i32 @__kmpc_target_init(%struct.ident_t* @[[GLOB1:[0-9]+]], i8 1, i1 false, i1 true)
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; CHECK-NEXT: [[EXEC_USER_CODE:%.*]] = icmp eq i32 [[TMP0]], -1
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; CHECK-NEXT: br i1 [[EXEC_USER_CODE]], label [[USER_CODE_ENTRY:%.*]], label [[WORKER_EXIT:%.*]]
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; CHECK: user_code.entry:
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; CHECK-NEXT: store i8 0, i8* @G, align 1
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; CHECK-NEXT: call void @__kmpc_target_deinit(%struct.ident_t* @[[GLOB1]], i8 1, i1 true)
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; CHECK-NEXT: ret void
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; CHECK: worker.exit:
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; CHECK-NEXT: ret void
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;
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entry:
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%0 = call i32 @__kmpc_target_init(%struct.ident_t* @1, i8 1, i1 true, i1 true)
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%exec_user_code = icmp eq i32 %0, -1
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br i1 %exec_user_code, label %user_code.entry, label %worker.exit
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user_code.entry: ; preds = %entry
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; Ensure we see a 0 here as the kernel doesn't have parallel regions and we want
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; generic execution.
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; TODO: This is not perfect. We should rather go for SPMD mode and tell the runtime
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; to only spawn a single thread. Further, we then should not guard any code.
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%isSPMD = call i8 @__kmpc_is_spmd_exec_mode()
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store i8 %isSPMD, i8* @G
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call void @bar() #2
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call void @__kmpc_target_deinit(%struct.ident_t* @1, i8 1, i1 true)
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ret void
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worker.exit: ; preds = %entry
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ret void
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}
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declare i8 @__kmpc_is_spmd_exec_mode()
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declare i32 @__kmpc_target_init(%struct.ident_t*, i8, i1, i1)
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declare void @__kmpc_target_deinit(%struct.ident_t*, i8, i1)
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; Function Attrs: convergent nounwind
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define hidden void @bar() #1 {
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; CHECK: Function Attrs: alwaysinline convergent nounwind
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; CHECK-LABEL: @bar(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: ret void
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;
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entry:
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ret void
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}
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attributes #0 = { convergent norecurse nounwind "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="sm_70" "target-features"="+ptx32,+sm_70" }
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attributes #1 = { convergent nounwind "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="sm_70" "target-features"="+ptx32,+sm_70" }
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attributes #2 = { convergent }
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!omp_offload.info = !{!0}
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!nvvm.annotations = !{!1}
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!llvm.module.flags = !{!2, !3, !4, !5, !6}
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!llvm.ident = !{!7}
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!0 = !{i32 0, i32 64770, i32 -1064087614, !"foo", i32 4, i32 0}
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!1 = !{void ()* @__omp_offloading_fd02_c0934fc2_foo_l4, !"kernel", i32 1}
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!2 = !{i32 1, !"wchar_size", i32 4}
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!3 = !{i32 7, !"openmp", i32 50}
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!4 = !{i32 7, !"openmp-device", i32 50}
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!5 = !{i32 7, !"PIC Level", i32 2}
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!6 = !{i32 7, !"frame-pointer", i32 2}
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!7 = !{!"clang version 14.0.0"}
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