llvm codegen: fix f16,f32,f64 nan bitcasts

@bitCast from integer NaN representation to float NaN resulted in
changed bits in float. This only happened with signaled NaN.

- added test for signaled NaN
- added tests for quiet NaN (for completeness)

closes #14198

1 files changed, 18 insertions, 0 deletions

diff --git a/test/behavior/bugs/14198.zig b/test/behavior/bugs/14198.zig
new file mode 100644
index 0000000000..92a33f4589
--- /dev/null
+++ b/test/behavior/bugs/14198.zig
@@ -0,0 +1,18 @@
+const std = @import("std");
+const math = std.math;
+const mem = std.mem;
+const testing = std.testing;
+
+test "nan memory equality" {
+    // signaled
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.nan_u16), mem.asBytes(&math.nan_f16)));
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.nan_u32), mem.asBytes(&math.nan_f32)));
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.nan_u64), mem.asBytes(&math.nan_f64)));
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.nan_u128), mem.asBytes(&math.nan_f128)));
+
+    // quiet
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.qnan_u16), mem.asBytes(&math.qnan_f16)));
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.qnan_u32), mem.asBytes(&math.qnan_f32)));
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.qnan_u64), mem.asBytes(&math.qnan_f64)));
+    try testing.expect(mem.eql(u8, mem.asBytes(&math.qnan_u128), mem.asBytes(&math.qnan_f128)));
+}