allow libm_intrinsics fallback

Author: djdisodo

crates/rustc_codegen_spirv/src/builder/builder_methods.rs

@@ -2325,17 +2325,19 @@ impl<'a, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'tcx> {
             .get(&callee_val)
             .copied();
         if let Some(libm_intrinsic) = libm_intrinsic {
-            let result = self.call_libm_intrinsic(libm_intrinsic, result_type, args);
-            if result_type != result.ty {
-                bug!(
-                    "Mismatched libm result type for {:?}: expected {}, got {}",
-                    libm_intrinsic,
-                    self.debug_type(result_type),
-                    self.debug_type(result.ty),
-                );
+            if let Some(result) = self.call_libm_intrinsic(libm_intrinsic, result_type, args) {
+                if result_type != result.ty {
+                    bug!(
+                        "Mismatched libm result type for {:?}: expected {}, got {}",
+                        libm_intrinsic,
+                        self.debug_type(result_type),
+                        self.debug_type(result.ty),
+                    );
+                }
+                return result;
             }
-            result
-        } else if [self.panic_fn_id.get(), self.panic_bounds_check_fn_id.get()]
+        }
+        if [self.panic_fn_id.get(), self.panic_bounds_check_fn_id.get()]
             .contains(&Some(callee_val))
         {
             // HACK(eddyb) redirect builtin panic calls to an abort, to avoid

crates/rustc_codegen_spirv/src/builder/libm_intrinsics.rs

@@ -201,8 +201,8 @@ impl Builder<'_, '_> {
         intrinsic: LibmIntrinsic,
         result_type: Word,
         args: &[SpirvValue],
-    ) -> SpirvValue {
-        match intrinsic {
+    ) -> Option<SpirvValue> {
+        Some(match intrinsic {
             LibmIntrinsic::GLOp(op) => self.gl_op(op, result_type, args),
             LibmIntrinsic::Custom(LibmCustomIntrinsic::SinCos) => {
                 assert_eq!(args.len(), 1);
@@ -258,6 +258,7 @@ impl Builder<'_, '_> {
                 let one = self.constant_float(exp.ty, 1.0);
                 self.sub(exp, one)
             }
+            /*
             LibmIntrinsic::Custom(LibmCustomIntrinsic::Erf) => {
                 let undef = self.undef(result_type);
                 self.zombie(undef.def(self), "Erf not supported yet");
@@ -348,6 +349,8 @@ impl Builder<'_, '_> {
                 self.zombie(undef.def(self), "Scalbn not supported yet");
                 undef
             }
-        }
+             */
+            _ => return None
+        })
     }
 }