[llvm] [EarlyIfConverter] Fix reg killed twice after early-if-predicator and ifcvt (PR #133554)

[Juan Manuel Martinez Caamaño via llvm-commits]

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@@ -0,0 +1,52 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+# RUN: llc -mtriple=hexagon -run-pass early-if-predicator %s -o - -verify-machineinstrs | FileCheck %s
+
+# Test that "killed" flag on the same virtual register in merged blocks is
+# removed for the first spliced block and is saved for the second one.
+# Otherwise, register will be killed twice in a single block in the resulting
+# MIR, which is incorrect.
+
+---
+name:            my_func
+alignment:       16
+tracksRegLiveness: true
+liveins:
+  - { reg: '$r0', virtual-reg: '%0' }
+  - { reg: '$r1', virtual-reg: '%1' }
+body:             |
+  ; CHECK-LABEL: name: my_func
+  ; CHECK: bb.0:
+  ; CHECK-NEXT:   liveins: $r0, $r1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:intregs = COPY $r0
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:intregs = COPY $r1
+  ; CHECK-NEXT:   [[S2_tstbit_i:%[0-9]+]]:predregs = S2_tstbit_i [[COPY1]], 0
+  ; CHECK-NEXT:   S4_storeirif_io [[S2_tstbit_i]], [[COPY]], 0, 1
+  ; CHECK-NEXT:   S4_storeirit_io [[S2_tstbit_i]], killed [[COPY]], 0, 1
+  ; CHECK-NEXT:   PS_jmpret $r31, implicit-def dead $pc
+  bb.0:
+    successors: %bb.1(0x40000000), %bb.2(0x40000000)
+    liveins: $r0, $r1
+
+    %0:intregs = COPY $r0
+    %1:intregs = COPY $r1
+    %2:predregs = S2_tstbit_i %1, 0
+    J2_jumpf %2, %bb.2, implicit-def dead $pc
+    J2_jump %bb.1, implicit-def dead $pc
+
+  bb.1:
+    successors: %bb.3(0x80000000)
+
+    S4_storeiri_io killed %0, 0, 1
+    J2_jump %bb.3, implicit-def dead $pc
+
+  bb.2:
+    successors: %bb.3(0x80000000)
+
+    S4_storeiri_io killed %0, 0, 1
----------------
jmmartinez wrote:

Would it be possible to use `S4_storeiri_io killed %0, 0, 2` in a similar way to the aarch64 test? It's easier to track the associated CHECK in the generated code.

https://github.com/llvm/llvm-project/pull/133554