diff --git a/compiler/rustc_passes/src/liveness.rs b/compiler/rustc_passes/src/liveness.rs index ae810b9e79a5f..7288015e17029 100644 --- a/compiler/rustc_passes/src/liveness.rs +++ b/compiler/rustc_passes/src/liveness.rs @@ -1174,7 +1174,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> { } } hir::InlineAsmOperand::InOut { expr, .. } => { - succ = self.write_place(expr, succ, ACC_READ | ACC_WRITE); + succ = self.write_place(expr, succ, ACC_READ | ACC_WRITE | ACC_USE); } hir::InlineAsmOperand::SplitInOut { out_expr, .. } => { if let Some(expr) = out_expr { diff --git a/src/test/ui/liveness/liveness-asm.rs b/src/test/ui/liveness/liveness-asm.rs new file mode 100644 index 0000000000000..e64335a8cc589 --- /dev/null +++ b/src/test/ui/liveness/liveness-asm.rs @@ -0,0 +1,43 @@ +// Ensure inout asm! operands are marked as used by the liveness pass + +// check-pass + +#![feature(asm)] +#![allow(dead_code)] +#![warn(unused_assignments)] +#![warn(unused_variables)] + +// Test the single inout case +unsafe fn f1(mut src: *const u8) { + asm!("/*{0}*/", inout(reg) src); //~ WARN value assigned to `src` is never read +} + +unsafe fn f2(mut src: *const u8) -> *const u8 { + asm!("/*{0}*/", inout(reg) src); + src +} + +// Test the split inout case +unsafe fn f3(mut src: *const u8) { + asm!("/*{0}*/", inout(reg) src => src); //~ WARN value assigned to `src` is never read +} + +unsafe fn f4(mut src: *const u8) -> *const u8 { + asm!("/*{0}*/", inout(reg) src => src); + src +} + +// Tests the use of field projections +struct S { + field: *mut u8, +} + +unsafe fn f5(src: &mut S) { + asm!("/*{0}*/", inout(reg) src.field); +} + +unsafe fn f6(src: &mut S) { + asm!("/*{0}*/", inout(reg) src.field => src.field); +} + +fn main() {} diff --git a/src/test/ui/liveness/liveness-asm.stderr b/src/test/ui/liveness/liveness-asm.stderr new file mode 100644 index 0000000000000..b8c04b5c4429e --- /dev/null +++ b/src/test/ui/liveness/liveness-asm.stderr @@ -0,0 +1,23 @@ +warning: value assigned to `src` is never read + --> $DIR/liveness-asm.rs:12:32 + | +LL | asm!("/*{0}*/", inout(reg) src); + | ^^^ + | +note: the lint level is defined here + --> $DIR/liveness-asm.rs:7:9 + | +LL | #![warn(unused_assignments)] + | ^^^^^^^^^^^^^^^^^^ + = help: maybe it is overwritten before being read? + +warning: value assigned to `src` is never read + --> $DIR/liveness-asm.rs:22:39 + | +LL | asm!("/*{0}*/", inout(reg) src => src); + | ^^^ + | + = help: maybe it is overwritten before being read? + +warning: 2 warnings emitted +