spirv: add -fstructured-cfg option

This enables the compiler to generate a structured cfg even in opencl,
even if it is not strictly required by the SPIR-V Kernel specification.

1 files changed, 8 insertions, 1 deletions

diff --git a/src/main.zig b/src/main.zig
index 641dd04164..11e40f09ca 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -493,6 +493,8 @@ const usage_build_generic =
     \\    msvc                    Use msvc include paths (must be present on the system)
     \\    gnu                     Use mingw include paths (distributed with Zig)
     \\    none                    Do not use any autodetected include paths
+    \\  -fstructured-cfg          (SPIR-V) force SPIR-V kernels to use structured control flow
+    \\  -fno-structured-cfg       (SPIR-V) force SPIR-V kernels to not use structured control flow
     \\
     \\Link Options:
     \\  -l[lib], --library [lib]       Link against system library (only if actually used)
@@ -913,7 +915,7 @@ fn buildOutputType(
     var pdb_out_path: ?[]const u8 = null;
     var dwarf_format: ?std.dwarf.Format = null;
     var error_limit: ?Module.ErrorInt = null;
-
+    var want_structured_cfg: ?bool = null;
     // e.g. -m3dnow or -mno-outline-atomics. They correspond to std.Target llvm cpu feature names.
     // This array is populated by zig cc frontend and then has to be converted to zig-style
     // CPU features.
@@ -1070,6 +1072,10 @@ fn buildOutputType(
                             if (mem.eql(u8, next_arg, "--")) break;
                             try extra_rcflags.append(next_arg);
                         }
+                    } else if (mem.startsWith(u8, arg, "-fstructured-cfg")) {
+                        want_structured_cfg = true;
+                    } else if (mem.startsWith(u8, arg, "-fno-structured-cfg")) {
+                        want_structured_cfg = false;
                     } else if (mem.eql(u8, arg, "--color")) {
                         const next_arg = args_iter.next() orelse {
                             fatal("expected [auto|on|off] after --color", .{});
@@ -3595,6 +3601,7 @@ fn buildOutputType(
         .error_tracing = error_tracing,
         .pdb_out_path = pdb_out_path,
         .error_limit = error_limit,
+        .want_structured_cfg = want_structured_cfg,
     }) catch |err| switch (err) {
         error.LibCUnavailable => {
             const target = target_info.target;