[clang] [CIR] Upstream CastOp and scalar conversions (PR #130690)

[Andy Kaylor via cfe-commits]

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@@ -0,0 +1,79 @@
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s
+
+unsigned char cxxstaticcast_0(unsigned int x) {
+  return static_cast<unsigned char>(x);
+}
+
+// CHECK: cir.func @cxxstaticcast_0
+// CHECK:    %0 = cir.alloca !cir.int<u, 32>, !cir.ptr<!cir.int<u, 32>>, ["x", init] {alignment = 4 : i64}
+// CHECK:    cir.store %arg0, %0 : !cir.int<u, 32>, !cir.ptr<!cir.int<u, 32>>
+// CHECK:    %1 = cir.load %0 : !cir.ptr<!cir.int<u, 32>>, !cir.int<u, 32>
+// CHECK:    %2 = cir.cast(integral, %1 : !cir.int<u, 32>), !cir.int<u, 8>
+// CHECK:    cir.return %2 : !cir.int<u, 8>
+// CHECK:  }
+
+
+int cStyleCasts_0(unsigned x1, int x2, float x3, short x4, double x5) {
+// CHECK: cir.func @cStyleCasts_0
+
+  char a = (char)x1; // truncate
+  // CHECK: %{{[0-9]+}} = cir.cast(integral, %{{[0-9]+}} : !cir.int<u, 32>), !cir.int<s, 8>
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andykaylor wrote:

Maybe add checks for lowering (to LLVM IR through clangir and using classic codegen) here also?

https://github.com/llvm/llvm-project/pull/130690