70343c8d44
The new interfaces provide getters and setters for the weight information about the branches of BranchOpInterface and RegionBranchOpInterface operations. These interfaces are done the same way as LLVM dialect's BranchWeightOpInterface. The plan is to produce this information in Flang, e.g. mark most probably "cold" code as such and allow LLVM to order basic blocks accordingly. An example of such a code is copy loops generated for arrays repacking - we can mark it as "cold" assuming that the copy will not happen dynamically. If the copy actually happens the overhead of the copy is probably high enough so that we may not care about the little overhead of jumping to the "cold" code and fetching it.
72 lines
1.5 KiB
LLVM
72 lines
1.5 KiB
LLVM
; RUN: mlir-translate -import-llvm -split-input-file %s | FileCheck %s
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; CHECK-LABEL: @cond_br
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define i64 @cond_br(i1 %arg1, i64 %arg2) {
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entry:
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; CHECK: llvm.cond_br
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; CHECK-SAME: weights([0, 3])
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br i1 %arg1, label %bb1, label %bb2, !prof !0
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bb1:
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ret i64 %arg2
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bb2:
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ret i64 %arg2
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}
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!0 = !{!"branch_weights", i32 0, i32 3}
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; // -----
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; CHECK-LABEL: @simple_switch(
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define i32 @simple_switch(i32 %arg1) {
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; CHECK: llvm.switch
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; CHECK: {branch_weights = array<i32: 42, 3, 5>}
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switch i32 %arg1, label %bbd [
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i32 0, label %bb1
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i32 9, label %bb2
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], !prof !0
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bb1:
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ret i32 %arg1
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bb2:
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ret i32 %arg1
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bbd:
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ret i32 %arg1
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}
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!0 = !{!"branch_weights", i32 42, i32 3, i32 5}
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; // -----
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; Verify that a single weight attached to a call is not translated.
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; The MLIR WeightedBranchOpInterface does not support this case.
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; CHECK: llvm.func @fn()
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declare i32 @fn()
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; CHECK-LABEL: @call_branch_weights
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define i32 @call_branch_weights() {
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; CHECK: llvm.call @fn() : () -> i32
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%1 = call i32 @fn(), !prof !0
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ret i32 %1
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}
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!0 = !{!"branch_weights", i32 42}
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; // -----
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declare void @foo()
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declare i32 @__gxx_personality_v0(...)
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; CHECK-LABEL: @invoke_branch_weights
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define i32 @invoke_branch_weights() personality ptr @__gxx_personality_v0 {
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; CHECK: llvm.invoke @foo() to ^bb2 unwind ^bb1 {branch_weights = array<i32: 42, 99>} : () -> ()
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invoke void @foo() to label %bb2 unwind label %bb1, !prof !0
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bb1:
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%1 = landingpad { ptr, i32 } cleanup
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br label %bb2
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bb2:
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ret i32 1
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}
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!0 = !{!"branch_weights", i32 42, i32 99}
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