[clang] [CIR][NFC] Simplify BoolAttr builders (PR #136366)

[Henrich Lauko via cfe-commits]

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@@ -692,9 +692,7 @@ mlir::LogicalResult CIRToLLVMConstantOpLowering::matchAndRewrite(
     // during a pass as long as they don't live past the end of the pass.
     attr = op.getValue();
   } else if (mlir::isa<cir::BoolType>(op.getType())) {
-    int value = (op.getValue() ==
-                 cir::BoolAttr::get(getContext(),
-                                    cir::BoolType::get(getContext()), true));
+    int value = (op.getValue() == cir::BoolAttr::get(getContext(), true));
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xlauko wrote:

This entire function might be more nicer in terms of cast to attributes directly, not dispatch based on types.

Also nobody guarantees, that if attribute has `cir::BoolType` it is actually `cir::BoolAttr`,
so the previous code might have returned false even in cases that attribute hold "true" value.

I will look into it in next PR.

https://github.com/llvm/llvm-project/pull/136366