From 2ffa1dd392c1fe9c23a2f11f7b7a293a744c05ce Mon Sep 17 00:00:00 2001
From: sayantn <sayantn05@gmail.com>
Date: Thu, 5 Jun 2025 20:41:41 +0530
Subject: [PATCH] Implement `simd_round_ties_even` for miri, cg_clif and cg_gcc

---
 compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs | 5 ++++-
 compiler/rustc_codegen_gcc/src/intrinsic/simd.rs        | 2 ++
 src/tools/miri/src/intrinsics/simd.rs                   | 2 ++
 src/tools/miri/tests/pass/intrinsics/portable-simd.rs   | 8 ++++++++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
index 46a441488fa6..f928ad8bc021 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs
@@ -495,7 +495,8 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
         | sym::simd_flog
         | sym::simd_flog10
         | sym::simd_flog2
-        | sym::simd_round => {
+        | sym::simd_round
+        | sym::simd_round_ties_even => {
             intrinsic_args!(fx, args => (a); intrinsic);
 
             if !a.layout().ty.is_simd() {
@@ -526,6 +527,8 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
                     (sym::simd_flog2, types::F64) => "log2",
                     (sym::simd_round, types::F32) => "roundf",
                     (sym::simd_round, types::F64) => "round",
+                    (sym::simd_round_ties_even, types::F32) => "rintf",
+                    (sym::simd_round_ties_even, types::F64) => "rint",
                     _ => unreachable!("{:?}", intrinsic),
                 };
                 fx.lib_call(
diff --git a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
index 82ef0d0b13a4..18ba1ca3d77e 100644
--- a/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
+++ b/compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
@@ -779,6 +779,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             sym::simd_fsin => "sin",
             sym::simd_fsqrt => "sqrt",
             sym::simd_round => "round",
+            sym::simd_round_ties_even => "rint",
             sym::simd_trunc => "trunc",
             _ => return_error!(InvalidMonomorphization::UnrecognizedIntrinsic { span, name }),
         };
@@ -826,6 +827,7 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
             | sym::simd_fsin
             | sym::simd_fsqrt
             | sym::simd_round
+            | sym::simd_round_ties_even
             | sym::simd_trunc
     ) {
         return simd_simple_float_intrinsic(name, in_elem, in_ty, in_len, bx, span, args);
diff --git a/src/tools/miri/src/intrinsics/simd.rs b/src/tools/miri/src/intrinsics/simd.rs
index dbe193bdbda8..da674d8022fe 100644
--- a/src/tools/miri/src/intrinsics/simd.rs
+++ b/src/tools/miri/src/intrinsics/simd.rs
@@ -37,6 +37,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             | "ceil"
             | "floor"
             | "round"
+            | "round_ties_even"
             | "trunc"
             | "fsqrt"
             | "fsin"
@@ -72,6 +73,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                     "ceil" => Op::Round(rustc_apfloat::Round::TowardPositive),
                     "floor" => Op::Round(rustc_apfloat::Round::TowardNegative),
                     "round" => Op::Round(rustc_apfloat::Round::NearestTiesToAway),
+                    "round_ties_even" => Op::Round(rustc_apfloat::Round::NearestTiesToEven),
                     "trunc" => Op::Round(rustc_apfloat::Round::TowardZero),
                     "ctlz" => Op::Numeric(sym::ctlz),
                     "ctpop" => Op::Numeric(sym::ctpop),
diff --git a/src/tools/miri/tests/pass/intrinsics/portable-simd.rs b/src/tools/miri/tests/pass/intrinsics/portable-simd.rs
index e14ce51f35a3..726d4c01cc3f 100644
--- a/src/tools/miri/tests/pass/intrinsics/portable-simd.rs
+++ b/src/tools/miri/tests/pass/intrinsics/portable-simd.rs
@@ -569,6 +569,10 @@ fn simd_round() {
         f32x4::from_array([0.9, 1.001, 2.0, -4.5]).round(),
         f32x4::from_array([1.0, 1.0, 2.0, -5.0])
     );
+    assert_eq!(
+        unsafe { intrinsics::simd_round_ties_even(f32x4::from_array([0.9, 1.001, 2.0, -4.5])) },
+        f32x4::from_array([1.0, 1.0, 2.0, -4.0])
+    );
     assert_eq!(
         f32x4::from_array([0.9, 1.001, 2.0, -4.5]).trunc(),
         f32x4::from_array([0.0, 1.0, 2.0, -4.0])
@@ -586,6 +590,10 @@ fn simd_round() {
         f64x4::from_array([0.9, 1.001, 2.0, -4.5]).round(),
         f64x4::from_array([1.0, 1.0, 2.0, -5.0])
     );
+    assert_eq!(
+        unsafe { intrinsics::simd_round_ties_even(f64x4::from_array([0.9, 1.001, 2.0, -4.5])) },
+        f64x4::from_array([1.0, 1.0, 2.0, -4.0])
+    );
     assert_eq!(
         f64x4::from_array([0.9, 1.001, 2.0, -4.5]).trunc(),
         f64x4::from_array([0.0, 1.0, 2.0, -4.0])