fix lower int_to_bool cast

Author: bruteforceboy

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -612,10 +612,16 @@ class CIRBrCondOpLowering
                   mlir::ConversionPatternRewriter &rewriter) const override {
     mlir::Value i1Condition;
 
+    auto hasOneUse = false;
+    if (auto defOp = brOp.getCond().getDefiningOp())
+      if (defOp->getResult(0).hasOneUse())
+        hasOneUse = true;
+
     if (auto defOp = adaptor.getCond().getDefiningOp()) {
       if (auto zext = dyn_cast<mlir::LLVM::ZExtOp>(defOp)) {
         if (zext->use_empty() &&
-            zext->getOperand(0).getType() == rewriter.getI1Type()) {
+            zext->getOperand(0).getType() == rewriter.getI1Type() &&
+            hasOneUse) {
           i1Condition = zext->getOperand(0);
           rewriter.eraseOp(zext);
         }

clang/test/CIR/Lowering/zext-cond.c

@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -fclangir-mem2reg -emit-llvm %s -o %t.ll
+
+#include <stdbool.h>
+
+bool test() {
+  bool x = false;
+  if (x) {
+    bool u = x;
+    return u;
+  }
+  return x;
+}