black_box: disassemble compiletest

Author: Firestar99

tests/compiletests/ui/lang/core/intrinsics/black_box.rs

@@ -1,5 +1,6 @@
 // Test black_box intrinsic
 // build-pass
+// compile-flags: -C llvm-args=--disassemble-fn=black_box::disassemble
 
 #![allow(internal_features)]
 #![feature(core_intrinsics)]
@@ -9,7 +10,14 @@ use core::hint::black_box;
 use spirv_std::spirv;
 
 #[spirv(compute(threads(1)))]
-pub fn main() {
+pub fn main(#[spirv(descriptor_set = 0, binding = 0, storage_buffer)] out: &mut [u32]) {
+    let result = disassemble();
+    for i in 0..result.len() {
+        out[i] = result[i];
+    }
+}
+
+pub fn disassemble() -> [u32; 8] {
     // Test with various types
     let x = 42i32;
     let y = black_box(x);
@@ -26,4 +34,15 @@ pub fn main() {
     // Test with references
     let data = 100u32;
     let ref_data = black_box(&data);
+
+    [
+        y as u32,
+        f32::to_bits(b),
+        w[0],
+        w[1],
+        w[2],
+        w[3],
+        result,
+        *ref_data,
+    ]
 }

tests/compiletests/ui/lang/core/intrinsics/black_box.stderr

@@ -1,4 +1,17 @@
 warning: black_box intrinsic does not prevent optimization in Rust GPU
 
+%1 = OpFunction  %2  None %3
+%4 = OpLabel
+OpLine %5 34 17
+%6 = OpIAdd  %7  %8 %9
+OpLine %5 40 5
+%10 = OpBitcast  %7  %11
+OpLine %12 1092 17
+%13 = OpBitcast  %7  %14
+OpLine %5 40 4
+%15 = OpCompositeConstruct  %2  %10 %13 %16 %17 %18 %19 %6 %20
+OpNoLine
+OpReturnValue %15
+OpFunctionEnd
 warning: 1 warning emitted