Remove support for floating-point constants in asm!

Floating-point constants aren't very useful anyways and this simplifies
the code since the type check can now be done in typeck.

compiler/rustc_codegen_ssa/src/common.rs

@@ -219,8 +219,6 @@ pub fn asm_const_to_str<'tcx>(
             ty::IntTy::I128 => (value as i128).to_string(),
             ty::IntTy::Isize => unreachable!(),
         },
-        ty::Float(ty::FloatTy::F32) => f32::from_bits(value as u32).to_string(),
-        ty::Float(ty::FloatTy::F64) => f64::from_bits(value as u64).to_string(),
         _ => span_bug!(sp, "asm const has bad type {}", ty_and_layout.ty),
     }
 }

compiler/rustc_passes/src/intrinsicck.rs

@@ -347,7 +347,7 @@ impl ExprVisitor<'tcx> {
     }
 
     fn check_asm(&self, asm: &hir::InlineAsm<'tcx>) {
-        for (idx, (op, op_sp)) in asm.operands.iter().enumerate() {
+        for (idx, (op, _)) in asm.operands.iter().enumerate() {
             match *op {
                 hir::InlineAsmOperand::In { reg, ref expr } => {
                     self.check_asm_operand_type(idx, reg, expr, asm.template, None);
@@ -372,19 +372,7 @@ impl ExprVisitor<'tcx> {
                         );
                     }
                 }
-                hir::InlineAsmOperand::Const { ref anon_const } => {
+                hir::InlineAsmOperand::Const { .. } | hir::InlineAsmOperand::Sym { .. } => {}
-                    let anon_const_def_id = self.tcx.hir().local_def_id(anon_const.hir_id);
-                    let value = ty::Const::from_anon_const(self.tcx, anon_const_def_id);
-                    match value.ty.kind() {
-                        ty::Int(_) | ty::Uint(_) | ty::Float(_) => {}
-                        _ => {
-                            let msg =
-                                "asm `const` arguments must be integer or floating-point values";
-                            self.tcx.sess.span_err(*op_sp, msg);
-                        }
-                    }
-                }
-                hir::InlineAsmOperand::Sym { .. } => {}
             }
         }
     }
@@ -405,33 +393,6 @@ impl Visitor<'tcx> for ItemVisitor<'tcx> {
         ExprVisitor { tcx: self.tcx, param_env, typeck_results }.visit_body(body);
         self.visit_body(body);
     }
-
-    fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
-        if let hir::ItemKind::GlobalAsm(asm) = item.kind {
-            for (op, op_sp) in asm.operands {
-                match *op {
-                    hir::InlineAsmOperand::Const { ref anon_const } => {
-                        let anon_const_def_id = self.tcx.hir().local_def_id(anon_const.hir_id);
-                        let value = ty::Const::from_anon_const(self.tcx, anon_const_def_id);
-                        match value.ty.kind() {
-                            ty::Int(_) | ty::Uint(_) | ty::Float(_) => {}
-                            _ => {
-                                let msg = "asm `const` arguments must be integer or floating-point values";
-                                self.tcx.sess.span_err(*op_sp, msg);
-                            }
-                        }
-                    }
-                    hir::InlineAsmOperand::In { .. }
-                    | hir::InlineAsmOperand::Out { .. }
-                    | hir::InlineAsmOperand::InOut { .. }
-                    | hir::InlineAsmOperand::SplitInOut { .. }
-                    | hir::InlineAsmOperand::Sym { .. } => unreachable!(),
-                }
-            }
-        }
-
-        intravisit::walk_item(self, item);
-    }
 }
 
 impl Visitor<'tcx> for ExprVisitor<'tcx> {

compiler/rustc_typeck/src/check/mod.rs

@@ -554,10 +554,8 @@ fn typeck_with_fallback<'tcx>(
                                 _ => false,
                             }) =>
                         {
-                            fcx.next_ty_var(TypeVariableOrigin {
+                            // Inline assembly constants must be integers.
-                                kind: TypeVariableOriginKind::MiscVariable,
+                            fcx.next_int_var()
-                                span,
-                            })
                         }
                         _ => fallback(),
                     },

src/doc/unstable-book/src/library-features/asm.md

@@ -509,7 +509,7 @@ Several types of operands are supported:
   - Identical to `inout` except that the register allocator can reuse a register allocated to an `in` (this can happen if the compiler knows the `in` has the same initial value as the `inlateout`).
   - You should only write to the register after all inputs are read, otherwise you may clobber an input.
 * `const <expr>`
-  - `<expr>` must be an integer or floating-point constant expression.
+  - `<expr>` must be an integer constant expression.
   - The value of the expression is formatted as a string and substituted directly into the asm template string.
 * `sym <path>`
   - `<path>` must refer to a `fn` or `static`.

src/test/ui/asm/type-check-1.rs

@@ -1,6 +1,6 @@
 // only-x86_64
 
-#![feature(asm)]
+#![feature(asm, global_asm)]
 
 fn main() {
     unsafe {
@@ -39,5 +39,25 @@ fn main() {
         asm!("{}", const const_bar(0));
         asm!("{}", const const_bar(x));
         //~^ ERROR attempt to use a non-constant value in a constant
+
+        // Const operands must be integer and must be constants.
+
+        asm!("{}", const 0);
+        asm!("{}", const 0i32);
+        asm!("{}", const 0i128);
+        asm!("{}", const 0f32);
+        //~^ ERROR mismatched types
+        asm!("{}", const 0 as *mut u8);
+        //~^ ERROR mismatched types
     }
 }
+
+// Const operands must be integer or floats, and must be constants.
+
+global_asm!("{}", const 0);
+global_asm!("{}", const 0i32);
+global_asm!("{}", const 0i128);
+global_asm!("{}", const 0f32);
+//~^ ERROR mismatched types
+global_asm!("{}", const 0 as *mut u8);
+//~^ ERROR mismatched types

src/test/ui/asm/type-check-1.stderr

@@ -64,7 +64,37 @@ LL |         asm!("{}", inout(reg) v[..]);
    = help: the trait `Sized` is not implemented for `[u64]`
    = note: all inline asm arguments must have a statically known size
 
-error: aborting due to 8 previous errors
+error[E0308]: mismatched types
+  --> $DIR/type-check-1.rs:48:26
+   |
+LL |         asm!("{}", const 0f32);
+   |                          ^^^^ expected integer, found `f32`
 
-Some errors have detailed explanations: E0277, E0435.
+error[E0308]: mismatched types
+  --> $DIR/type-check-1.rs:50:26
+   |
+LL |         asm!("{}", const 0 as *mut u8);
+   |                          ^^^^^^^^^^^^ expected integer, found *-ptr
+   |
+   = note:     expected type `{integer}`
+           found raw pointer `*mut u8`
+
+error[E0308]: mismatched types
+  --> $DIR/type-check-1.rs:60:25
+   |
+LL | global_asm!("{}", const 0f32);
+   |                         ^^^^ expected integer, found `f32`
+
+error[E0308]: mismatched types
+  --> $DIR/type-check-1.rs:62:25
+   |
+LL | global_asm!("{}", const 0 as *mut u8);
+   |                         ^^^^^^^^^^^^ expected integer, found *-ptr
+   |
+   = note:     expected type `{integer}`
+           found raw pointer `*mut u8`
+
+error: aborting due to 12 previous errors
+
+Some errors have detailed explanations: E0277, E0308, E0435.
 For more information about an error, try `rustc --explain E0277`.

src/test/ui/asm/type-check-2.rs

@@ -1,6 +1,6 @@
 // only-x86_64
 
-#![feature(asm, global_asm, repr_simd, never_type)]
+#![feature(asm, repr_simd, never_type)]
 
 #[repr(simd)]
 struct SimdNonCopy(f32, f32, f32, f32);
@@ -26,14 +26,6 @@ fn main() {
         asm!("{}", inout(reg) v[0]);
         //~^ ERROR cannot borrow `v` as mutable, as it is not declared as mutable
 
-        // Const operands must be integer or floats, and must be constants.
-
-        asm!("{}", const 0);
-        asm!("{}", const 0i32);
-        asm!("{}", const 0f32);
-        asm!("{}", const 0 as *mut u8);
-        //~^ ERROR asm `const` arguments must be integer or floating-point values
-
         // This currently causes an ICE: https://github.com/rust-lang/rust/issues/81857
         // asm!("{}", const &0);
         // ERROR asm `const` arguments must be integer or floating-point values
@@ -90,11 +82,3 @@ fn main() {
         asm!("{}", in(reg) u);
     }
 }
-
-// Const operands must be integer or floats, and must be constants.
-
-global_asm!("{}", const 0);
-global_asm!("{}", const 0i32);
-global_asm!("{}", const 0f32);
-global_asm!("{}", const 0 as *mut u8);
-//~^ ERROR asm `const` arguments must be integer or floating-point values

src/test/ui/asm/type-check-2.stderr

@@ -1,19 +1,13 @@
-error: asm `const` arguments must be integer or floating-point values
-  --> $DIR/type-check-2.rs:34:20
-   |
-LL |         asm!("{}", const 0 as *mut u8);
-   |                    ^^^^^^^^^^^^^^^^^^
-
 error: arguments for inline assembly must be copyable
-  --> $DIR/type-check-2.rs:54:32
+  --> $DIR/type-check-2.rs:46:32
    |
 LL |         asm!("{}", in(xmm_reg) SimdNonCopy(0.0, 0.0, 0.0, 0.0));
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `SimdNonCopy` does not implement the Copy trait
 
-error: cannot use value of type `[closure@$DIR/type-check-2.rs:66:28: 66:38]` for inline assembly
+error: cannot use value of type `[closure@$DIR/type-check-2.rs:58:28: 58:38]` for inline assembly
-  --> $DIR/type-check-2.rs:66:28
+  --> $DIR/type-check-2.rs:58:28
    |
 LL |         asm!("{}", in(reg) |x: i32| x);
    |                            ^^^^^^^^^^
@@ -21,7 +15,7 @@ LL |         asm!("{}", in(reg) |x: i32| x);
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `Vec<i32>` for inline assembly
-  --> $DIR/type-check-2.rs:68:28
+  --> $DIR/type-check-2.rs:60:28
    |
 LL |         asm!("{}", in(reg) vec![0]);
    |                            ^^^^^^^
@@ -30,7 +24,7 @@ LL |         asm!("{}", in(reg) vec![0]);
    = note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: cannot use value of type `(i32, i32, i32)` for inline assembly
-  --> $DIR/type-check-2.rs:70:28
+  --> $DIR/type-check-2.rs:62:28
    |
 LL |         asm!("{}", in(reg) (1, 2, 3));
    |                            ^^^^^^^^^
@@ -38,7 +32,7 @@ LL |         asm!("{}", in(reg) (1, 2, 3));
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `[i32; 3]` for inline assembly
-  --> $DIR/type-check-2.rs:72:28
+  --> $DIR/type-check-2.rs:64:28
    |
 LL |         asm!("{}", in(reg) [1, 2, 3]);
    |                            ^^^^^^^^^
@@ -46,7 +40,7 @@ LL |         asm!("{}", in(reg) [1, 2, 3]);
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `fn() {main}` for inline assembly
-  --> $DIR/type-check-2.rs:80:31
+  --> $DIR/type-check-2.rs:72:31
    |
 LL |         asm!("{}", inout(reg) f);
    |                               ^
@@ -54,27 +48,21 @@ LL |         asm!("{}", inout(reg) f);
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
 error: cannot use value of type `&mut i32` for inline assembly
-  --> $DIR/type-check-2.rs:83:31
+  --> $DIR/type-check-2.rs:75:31
    |
 LL |         asm!("{}", inout(reg) r);
    |                               ^
    |
    = note: only integers, floats, SIMD vectors, pointers and function pointers can be used as arguments for inline assembly
 
-error: asm `const` arguments must be integer or floating-point values
-  --> $DIR/type-check-2.rs:99:19
-   |
-LL | global_asm!("{}", const 0 as *mut u8);
-   |                   ^^^^^^^^^^^^^^^^^^
-
 error: asm `sym` operand must point to a fn or static
-  --> $DIR/type-check-2.rs:47:24
+  --> $DIR/type-check-2.rs:39:24
    |
 LL |         asm!("{}", sym C);
    |                        ^
 
 error: asm `sym` operand must point to a fn or static
-  --> $DIR/type-check-2.rs:49:24
+  --> $DIR/type-check-2.rs:41:24
    |
 LL |         asm!("{}", sym x);
    |                        ^
@@ -109,7 +97,7 @@ LL |         let v: Vec<u64> = vec![0, 1, 2];
 LL |         asm!("{}", inout(reg) v[0]);
    |                               ^ cannot borrow as mutable
 
-error: aborting due to 15 previous errors
+error: aborting due to 13 previous errors
 
 Some errors have detailed explanations: E0381, E0596.
 For more information about an error, try `rustc --explain E0381`.