Port old change to latest main

Author: LegNeato

crates/rustc_codegen_spirv/src/builder/builder_methods.rs

@@ -210,21 +210,23 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             },
             SpirvType::Integer(width, true) => match width {
                 8 => self
-                    .constant_i8(self.span(), unsafe { std::mem::transmute(fill_byte) })
+                    .constant_i8(self.span(), unsafe {
+                        std::mem::transmute::<u8, i8>(fill_byte)
+                    })
                     .def(self),
                 16 => self
                     .constant_i16(self.span(), unsafe {
-                        std::mem::transmute(memset_fill_u16(fill_byte))
+                        std::mem::transmute::<u16, i16>(memset_fill_u16(fill_byte))
                     })
                     .def(self),
                 32 => self
                     .constant_i32(self.span(), unsafe {
-                        std::mem::transmute(memset_fill_u32(fill_byte))
+                        std::mem::transmute::<u32, i32>(memset_fill_u32(fill_byte))
                     })
                     .def(self),
                 64 => self
                     .constant_i64(self.span(), unsafe {
-                        std::mem::transmute(memset_fill_u64(fill_byte))
+                        std::mem::transmute::<u64, i64>(memset_fill_u64(fill_byte))
                     })
                     .def(self),
                 _ => self.fatal(format!(

crates/rustc_codegen_spirv/src/codegen_cx/constant.rs

@@ -18,11 +18,6 @@ impl<'tcx> CodegenCx<'tcx> {
         self.builder.def_constant_cx(ty, val, self)
     }
 
-    pub fn constant_i8(&self, span: Span, val: i8) -> SpirvValue {
-        let ty = SpirvType::Integer(8, true).def(span, self);
-        self.def_constant(ty, SpirvConst::U32(val as u32))
-    }
-
     pub fn constant_u8(&self, span: Span, val: u8) -> SpirvValue {
         self.constant_int_from_native_unsigned(span, val)
     }
@@ -47,9 +42,8 @@ impl<'tcx> CodegenCx<'tcx> {
         self.constant_int_from_native_unsigned(span, val)
     }
 
-    pub fn constant_i64(&self, span: Span, val: u64) -> SpirvValue {
-        let ty = SpirvType::Integer(64, true).def(span, self);
-        self.def_constant(ty, SpirvConst::U64(val))
+    pub fn constant_i64(&self, span: Span, val: i64) -> SpirvValue {
+        self.constant_int_from_native_signed(span, val)
     }
 
     pub fn constant_u64(&self, span: Span, val: u64) -> SpirvValue {