[llvm] [TableGen] New tblgen Pattern bit to disable DAG pattern imports during GISel (PR #88382)

[Pierre van Houtryve via llvm-commits]

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@@ -23,6 +25,10 @@ def INSN : I<(outs GPR32:$dst), (ins GPR32:$src1, complex:$src2), []>;
 
 //===- Bail out when we define a variable twice wrt complex suboperands. -===//
 
+#ifdef IGNORE
+let GISelShouldIgnore = 1 in
+#endif
+// CHECK0-NOT: warning: Skipped pattern: Error: {{.*}}
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Pierre-vh wrote:

nit: Can you rename this to something like `IGNORED` ? `CHECK0` doesn't tell much at first glance

https://github.com/llvm/llvm-project/pull/88382