Avoid mir_operand_get_const_val hack for simd_insert and simd_extract

Author: bjorn3

src/constant.rs

@@ -490,6 +490,11 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
 }
 
 /// Used only for intrinsic implementations that need a compile-time constant
+///
+/// All uses of this function are a bug inside stdarch. [`eval_mir_constant`]
+/// should be used everywhere, but for some vendor intrinsics stdarch forgets
+/// to wrap the immediate argument in `const {}`, necesitating this hack to get
+/// the correct value at compile time instead.
 pub(crate)fnmir_operand_get_const_val<'tcx>(
 fx:&FunctionCx<'_,'_,'tcx>,
 operand:&Operand<'tcx>,

src/intrinsics/simd.rs

@@ -268,10 +268,8 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
 let val = codegen_operand(fx,&val.node);
 
 // FIXME validate
-let idx_const = ifletSome(idx_const) =
-crate::constant::mir_operand_get_const_val(fx,&idx.node)
-{
- idx_const
+let idx_const = ifletSome(idx_const) = idx.node.constant(){
+crate::constant::eval_mir_constant(fx, idx_const).0.try_to_scalar_int().unwrap()
 }else{
  fx.tcx.dcx().span_fatal(span,"Index argument for `simd_insert` is not a constant");
 };
@@ -304,22 +302,12 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
 return;
 }
 
-let idx_const = ifletSome(idx_const) =
-crate::constant::mir_operand_get_const_val(fx,&idx.node)
-{
- idx_const
+let idx_const = ifletSome(idx_const) = idx.node.constant(){
+crate::constant::eval_mir_constant(fx, idx_const).0.try_to_scalar_int().unwrap()
 }else{
- fx.tcx.dcx().span_warn(span,"Index argument for `simd_extract` is not a constant");
-let trap_block = fx.bcx.create_block();
-let true_ = fx.bcx.ins().iconst(types::I8,1);
-let ret_block = fx.get_block(target);
- fx.bcx.ins().brif(true_, trap_block,&[], ret_block,&[]);
- fx.bcx.switch_to_block(trap_block);
-crate::trap::trap_unimplemented(
- fx,
-"Index argument for `simd_extract` is not a constant",
-);
-return;
+ fx.tcx
+.dcx()
+.span_fatal(span,"Index argument for `simd_extract` is not a constant");
 };
 
 let idx = idx_const.to_u32();