Add roundeven float intrinsics

Author: dsprenkels

compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs

@@ -497,6 +497,8 @@ pub(crate) fn codegen_intrinsic_call<'tcx>(
         truncf64(flt) -> f64 => trunc,
         roundf32(flt) -> f32 => roundf,
         roundf64(flt) -> f64 => round,
+        roundevenf32(flt) -> f32 => roundevenf,
+        roundevenf64(flt) -> f64 => roundeven,
 
         // trigonometry
         sinf32(flt) -> f32 => sinf,

compiler/rustc_codegen_llvm/src/context.rs

@@ -573,6 +573,8 @@ impl CodegenCx<'b, 'tcx> {
         ifn!("llvm.copysign.f64", fn(t_f64, t_f64) -> t_f64);
         ifn!("llvm.round.f32", fn(t_f32) -> t_f32);
         ifn!("llvm.round.f64", fn(t_f64) -> t_f64);
+        ifn!("llvm.roundeven.f32", fn(t_f32) -> t_f32);
+        ifn!("llvm.roundeven.f64", fn(t_f64) -> t_f64);
 
         ifn!("llvm.rint.f32", fn(t_f32) -> t_f32);
         ifn!("llvm.rint.f64", fn(t_f64) -> t_f64);

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -68,6 +68,8 @@ fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: Symbol) -> Option<&'ll Va
         sym::nearbyintf64 => "llvm.nearbyint.f64",
         sym::roundf32 => "llvm.round.f32",
         sym::roundf64 => "llvm.round.f64",
+        sym::roundevenf32 => "llvm.roundeven.f32",
+        sym::roundevenf64 => "llvm.roundeven.f64",
         _ => return None,
     };
     Some(cx.get_intrinsic(&llvm_name))

compiler/rustc_span/src/symbol.rs

@@ -931,6 +931,8 @@ symbols! {
         rlib,
         rotate_left,
         rotate_right,
+        roundevenf32,
+        roundevenf64,
         roundf32,
         roundf64,
         rt,

compiler/rustc_typeck/src/check/intrinsic.rs

@@ -247,6 +247,8 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
             sym::nearbyintf64 => (0, vec![tcx.types.f64], tcx.types.f64),
             sym::roundf32 => (0, vec![tcx.types.f32], tcx.types.f32),
             sym::roundf64 => (0, vec![tcx.types.f64], tcx.types.f64),
+            sym::roundevenf32 => (0, vec![tcx.types.f32], tcx.types.f32),
+            sym::roundevenf64 => (0, vec![tcx.types.f64], tcx.types.f64),
 
             sym::volatile_load | sym::unaligned_volatile_load => {
                 (1, vec![tcx.mk_imm_ptr(param(0))], param(0))