test/CodeGen/WebAssembly/irreducible-cfg.mir

# RUN: llc -mtriple=wasm32-unknown-unknown -run-pass wasm-fix-irreducible-control-flow %s -o - | FileCheck %s

# This tests if we correctly create at most 2 routing blocks per entry block,
# and also whether those routing blocks are generated in the correct place. If
# one of the predecessor is the layout predecessor of an entry, a routing block
# for the entry should be generated right after the layout predecessor.

--- |
  target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
  target triple = "wasm32-unknown-unknown"

  define void @test0() {
  pred0:
    ret void
  pred1:
    ret void
  entry0:
    ret void
  entry1:
    ret void
  }
...

---
# CHECK-LABEL: test0
name: test0
liveins:
  - { reg: '$arguments' }
body: |
  bb.0.pred0:
    successors: %bb.1, %bb.2
    liveins: $arguments
    %0:i32 = CONST_I32 100, implicit-def $arguments
    BR_IF %bb.2, %0:i32, implicit-def $arguments
  ; CHECK: bb.0.pred0:
    ; CHECK: BR_IF %bb.2, %0, implicit-def $arguments

  bb.1.pred1:
  ; predecessors: %bb.1
    successors: %bb.2, %bb.3
    BR_IF %bb.3, %0:i32, implicit-def $arguments
  ; CHECK: bb.1.pred1:
    ; CHECK: BR_IF %bb.7, %0, implicit-def $arguments
    ; This falls through to bb.2, so we don't need an additional BR here
    ; CHECK-NOT: BR

  ; Routing block for entry0, when predecessor is outside the loop
  ; This routing block is shared between the two predecessors: pred0 and pred1.
  ; CHECK: bb.2:
    ; CHECK: %1:i32 = CONST_I32 0, implicit-def $arguments
    ; CHECK: BR %bb.6, implicit-def $arguments

  bb.2.entry0:
  ; predecessors: %bb.0, %bb.1, %bb.1
    successors: %bb.3
    BR %bb.3, implicit-def $arguments
  ; CHECK: bb.3.entry0:
    ; CHECK: BR %bb.4, implicit-def $arguments

  ; Routing block for entry1, when predecessor is inside the loop
  ; CHECK: bb.4:
    ; CHECK: %1:i32 = CONST_I32 1, implicit-def $arguments
    ; CHECK: BR %bb.6, implicit-def $arguments

  bb.3.entry1:
  ; predecessors: %bb.1, %bb.2
    successors: %bb.2
    BR %bb.2, implicit-def $arguments
  ; CHECK: bb.5.entry1:
    ; CHECK: BR %bb.8, implicit-def $arguments

  ; Dispatch block
  ; CHECK: bb.6:
    ; CHECK: BR_TABLE_I32 %1, %bb.3, %bb.5, %bb.5, implicit-def $arguments

  ; Routing block for entry1, when predecessor is outside the loop
  ; CHECK: bb.7:
    ; CHECK: %1:i32 = CONST_I32 1, implicit-def $arguments
    ; CHECK: BR %bb.6, implicit-def $arguments

  ; Routing block for entry0, when predecessor is inside the loop
  ; CHECK: bb.8:
    ; CHECK: %1:i32 = CONST_I32 0, implicit-def $arguments
    ; CHECK: BR %bb.6, implicit-def $arguments