libunistring: 1.2 needs std=c18 for icc, add icc C++ flags update (#37607)

2 files changed, 12 insertions, 0 deletions

diff --git a/lib/spack/spack/compilers/intel.py b/lib/spack/spack/compilers/intel.py
index 3cae5e5873..4990da3cb0 100644
--- a/lib/spack/spack/compilers/intel.py
+++ b/lib/spack/spack/compilers/intel.py
@@ -93,6 +93,14 @@ class Intel(Compiler):
             return "-std=c1x"
 
     @property
+    def c18_flag(self):
+        # c18 supported since oneapi 2022, which is classic version 2021.5.0
+        if self.real_version < Version("21.5.0"):
+            raise UnsupportedCompilerFlag(self, "the C18 standard", "c18_flag", "< 21.5.0")
+        else:
+            return "-std=c18"
+
+    @property
     def cc_pic_flag(self):
         return "-fPIC"
 
diff --git a/lib/spack/spack/test/compilers/basics.py b/lib/spack/spack/test/compilers/basics.py
index 65c05ccbdf..ee31e50f53 100644
--- a/lib/spack/spack/test/compilers/basics.py
+++ b/lib/spack/spack/test/compilers/basics.py
@@ -461,9 +461,13 @@ def test_intel_flags():
     unsupported_flag_test("cxx14_flag", "intel@=14.0")
     supported_flag_test("cxx14_flag", "-std=c++1y", "intel@=15.0")
     supported_flag_test("cxx14_flag", "-std=c++14", "intel@=15.0.2")
+    unsupported_flag_test("cxx17_flag", "intel@=18")
+    supported_flag_test("cxx17_flag", "-std=c++17", "intel@=19.0")
     unsupported_flag_test("c99_flag", "intel@=11.0")
     supported_flag_test("c99_flag", "-std=c99", "intel@=12.0")
     unsupported_flag_test("c11_flag", "intel@=15.0")
+    supported_flag_test("c18_flag", "-std=c18", "intel@=21.5.0")
+    unsupported_flag_test("c18_flag", "intel@=21.4.0")
     supported_flag_test("c11_flag", "-std=c1x", "intel@=16.0")
     supported_flag_test("cc_pic_flag", "-fPIC", "intel@=1.0")
     supported_flag_test("cxx_pic_flag", "-fPIC", "intel@=1.0")