[Mlir-commits] [mlir] [mlir][ArmSME] Support filling liveness 'holes' in the tile allocator (PR #98350)
Benjamin Maxwell
llvmlistbot at llvm.org
Mon Jul 15 10:41:31 PDT 2024
================
@@ -430,3 +430,133 @@ func.func @cond_branch_with_backedge(%slice: vector<[4]xf32>) {
// Live here: %finalTileA, %finalTileB, %finalTileC, %finalTileD
return
}
+
+// -----
+
+// CHECK-LIVE-RANGE-LABEL: @fill_holes_in_tile_liveness
+// CHECK-LIVE-RANGE: ========== Coalesced Live Ranges:
+// CHECK-LIVE-RANGE: ^bb0:
+// CHECK-LIVE-RANGE: S arm_sme.get_tile
+// CHECK-LIVE-RANGE: E cf.cond_br
+// CHECK-LIVE-RANGE: ^bb1:
+// CHECK-LIVE-RANGE: S arm_sme.get_tile
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: E test.some_use
+// CHECK-LIVE-RANGE: cf.br
+// CHECK-LIVE-RANGE: ^bb2:
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: E test.some_use
+// CHECK-LIVE-RANGE: cf.br
+
+// Here there's a 'hole' in the liveness of %tileA (in bb1) where another value
+// can reuse the tile ID (0) assigned to %tileA.
+
+// CHECK-LABEL: @fill_holes_in_tile_liveness
+func.func @fill_holes_in_tile_liveness(%cond: i1) {
+ // CHECK: arm_sme.get_tile {tile_id = 0 : i32}
+ %tileA = arm_sme.get_tile : vector<[4]x[4]xf32>
+ cf.cond_br %cond, ^bb2, ^bb1
+^bb1:
+ // CHECK: arm_sme.get_tile {tile_id = 0 : i32}
+ %tileB = arm_sme.get_tile : vector<[4]x[4]xf32>
+ "test.dummy"(): () -> ()
+ "test.some_use"(%tileB) : (vector<[4]x[4]xf32>) -> ()
+ cf.br ^bb3
+^bb2:
+ "test.dummy"(): () -> ()
+ "test.dummy"(): () -> ()
+ "test.dummy"(): () -> ()
+ "test.some_use"(%tileA) : (vector<[4]x[4]xf32>) -> ()
+ cf.br ^bb3
+^bb3:
+ return
+}
+
+// -----
+
+// CHECK-LIVE-RANGE-LABEL: @holes_in_tile_liveness_inactive_overlaps
+// CHECK-LIVE-RANGE: ========== Coalesced Live Ranges:
+// CHECK-LIVE-RANGE: ^bb0:
+// CHECK-LIVE-RANGE: S arm_sme.get_tile
+// CHECK-LIVE-RANGE: E cf.cond_br
+// CHECK-LIVE-RANGE: ^bb1:
+// CHECK-LIVE-RANGE: S arm_sme.get_tile
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: | test.some_use
+// CHECK-LIVE-RANGE: | arm_sme.copy_tile
+// CHECK-LIVE-RANGE: E cf.br
+// CHECK-LIVE-RANGE: ^bb2:
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: | test.dummy
+// CHECK-LIVE-RANGE: |S arm_sme.get_tile
+// CHECK-LIVE-RANGE: E| test.some_use
+// CHECK-LIVE-RANGE: | arm_sme.copy_tile
+// CHECK-LIVE-RANGE: E cf.br
+// CHECK-LIVE-RANGE: ^bb3:
+// CHECK-LIVE-RANGE: E test.some_use
+// CHECK-LIVE-RANGE: func.return
+
+// This tests an edge case in inactive live ranges. The first live range is
+// inactive at the start of ^bb1. If the tile allocator did not check if the
+// second live range overlapped the first it would wrongly re-use tile ID 0
+// (as the first live range is inactive so tile ID 0 is free). This would mean
+// in ^bb2 two overlapping live ranges would have the same tile ID (bad!).
+
+// CHECK-LABEL: @holes_in_tile_liveness_inactive_overlaps
+func.func @holes_in_tile_liveness_inactive_overlaps(%cond: i1) {
----------------
MacDue wrote:
Yes, the point of this test is to check an edge case that an only occur if you attempt to fill the liveness holes.
https://github.com/llvm/llvm-project/pull/98350
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