[Mlir-commits] [mlir] [mlir][RemoveDeadValues] Simplify branch op handling using ub.poison (PR #182711)

[Fedor Nikolaev]

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@@ -476,6 +480,51 @@ func.func @kernel(%arg0: memref<18xf32>) {
 
 // -----
 
+// Test that RemoveDeadValues does not crash when gpu.launch appears in a block
+// with multiple predecessors. The dead branch operand (%c20) must be replaced
+// with ub.poison, gpu.launch and its grid/block size operands must be
+// preserved, and the live block argument must remain intact.
+//
+// CHECK-LABEL: func.func @gpu_launch_in_multi_predecessor_block
+// CHECK: arith.constant true
+// CHECK: cf.cond_br
+// CHECK: arith.constant 10
+// CHECK: cf.br ^[[BB3:bb[0-9]+]](%{{.*}} : i64)
+// CHECK: ub.poison
+// CHECK: cf.br ^[[BB3]](%{{.*}} : i64)
+// CHECK: ^[[BB3]](%{{.*}}: i64):
+// CHECK: return
+// CHECK-NOT: arith.constant 20
+//
+// CHECK-CANONICALIZE-LABEL: func.func @gpu_launch_in_multi_predecessor_block
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felichita wrote:

Done

https://github.com/llvm/llvm-project/pull/182711