[llvm] [MachineCSE] Enhance MachineCSE simple PRE to find common subexpressi… (PR #129860)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,126 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=amdgcn -run-pass=machine-cse -verify-machineinstrs -o - %s | FileCheck %s
+# RUN: llc -mtriple=amdgcn -passes=machine-cse -o - %s | FileCheck %s
+
+--- |
+  define amdgpu_kernel void @not_cse_completely(ptr addrspace(1), i32 %a, i1) {
+  entry:
+    br label %while.cond
+  while.cond:
+    %cmp = trunc i32 %a to i1
+    br i1 %cmp, label %if.then, label %if.else
+  if.then:
+    br label %if.end
+  if.else:
+    br label %if.end
+  if.end:
+    %cmp2 = trunc i32 %a to i1
+    br i1 %cmp, label %while.cond, label %while.end
+  while.end:
+    ret void
+  }
+...
+---
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arsenm wrote:

Add comment explaining test 

https://github.com/llvm/llvm-project/pull/129860