[clang] [CIR] Upstream minimal builtin function call support (PR #142981)

[Sirui Mu via cfe-commits]

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@@ -0,0 +1,78 @@
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s -check-prefix=LLVM
+// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-linux-gnu -Wno-unused-value -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=OGCG
+
+constexpr extern int cx_var = __builtin_is_constant_evaluated();
+
+// CIR: cir.global {{.*}} @cx_var = #cir.int<1> : !s32i
+// LLVM: @cx_var = {{.*}} i32 1
+// OGCG: @cx_var = {{.*}} i32 1
+
+constexpr extern float cx_var_single = __builtin_huge_valf();
+
+// CIR: cir.global {{.*}} @cx_var_single = #cir.fp<0x7F800000> : !cir.float
+// LLVM: @cx_var_single = {{.*}} float 0x7FF0000000000000
+// OGCG: @cx_var_single = {{.*}} float 0x7FF0000000000000
+
+constexpr extern long double cx_var_ld = __builtin_huge_vall();
+
+// CIR: cir.global {{.*}} @cx_var_ld = #cir.fp<0x7FFF8000000000000000> : !cir.long_double<!cir.f80>
+// LLVM: @cx_var_ld = {{.*}} x86_fp80 0xK7FFF8000000000000000
+// OGCG: @cx_var_ld = {{.*}} x86_fp80 0xK7FFF8000000000000000
+
+int is_constant_evaluated() {
+    return __builtin_is_constant_evaluated();
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Lancern wrote:

nit: reduce indentation

https://github.com/llvm/llvm-project/pull/142981