From 9901c39e0840f7cd4398530d0410c5ad3a6ddf8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9my=20Rakic?= <remy.rakic+github@gmail.com>
Date: Thu, 4 Mar 2021 23:23:51 +0100
Subject: [PATCH] convert `_mm512_slli_epi16` to const generics

---
 .../crates/core_arch/src/x86/avx512bw.rs        | 16 ++++++----------
 .../stdarch/crates/core_arch/src/x86/macros.rs  | 17 +++++++++++++++++
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
index 5f48d76cb7ff..61614f8ff361 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
@@ -5008,16 +5008,12 @@ pub unsafe fn _mm_maskz_sll_epi16(k: __mmask8, a: __m128i, count: __m128i) -> __
 /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm512_slli_epi16&expand=5301)
 #[inline]
 #[target_feature(enable = "avx512bw")]
-#[cfg_attr(test, assert_instr(vpsllw, imm8 = 5))]
-#[rustc_args_required_const(1)]
-pub unsafe fn _mm512_slli_epi16(a: __m512i, imm8: u32) -> __m512i {
+#[cfg_attr(test, assert_instr(vpsllw, IMM8 = 5))]
+#[rustc_legacy_const_generics(1)]
+pub unsafe fn _mm512_slli_epi16<const IMM8: u32>(a: __m512i) -> __m512i {
+    static_assert_imm_u8!(IMM8);
     let a = a.as_i16x32();
-    macro_rules! call {
-        ($imm8:expr) => {
-            vpslliw(a, $imm8)
-        };
-    }
-    let r = constify_imm8_sae!(imm8, call);
+    let r = vpslliw(a, IMM8);
     transmute(r)
 }
 
@@ -14476,7 +14472,7 @@ mod tests {
     #[simd_test(enable = "avx512bw")]
     unsafe fn test_mm512_slli_epi16() {
         let a = _mm512_set1_epi16(1 << 15);
-        let r = _mm512_slli_epi16(a, 1);
+        let r = _mm512_slli_epi16::<1>(a);
         let e = _mm512_set1_epi16(0);
         assert_eq_m512i(r, e);
     }
diff --git a/library/stdarch/crates/core_arch/src/x86/macros.rs b/library/stdarch/crates/core_arch/src/x86/macros.rs
index d4c8e363ba15..c22328024b19 100644
--- a/library/stdarch/crates/core_arch/src/x86/macros.rs
+++ b/library/stdarch/crates/core_arch/src/x86/macros.rs
@@ -32,6 +32,23 @@ macro_rules! static_assert_sae {
     };
 }
 
+// Helper struct used to trigger const eval errors when the unsigned const generic immediate value
+// `IMM` is out of `[MIN-MAX]` range.
+pub(crate) struct ValidateConstImmU32<const IMM: u32, const MIN: u32, const MAX: u32>;
+impl<const IMM: u32, const MIN: u32, const MAX: u32> ValidateConstImmU32<IMM, MIN, MAX> {
+    pub(crate) const VALID: () = {
+        let _ = 1 / ((IMM >= MIN && IMM <= MAX) as usize);
+    };
+}
+
+#[allow(unused_macros)]
+macro_rules! static_assert_imm_u8 {
+    ($imm:ident) => {
+        let _ =
+            $crate::core_arch::x86::macros::ValidateConstImmU32::<$imm, 0, { (1 << 8) - 1 }>::VALID;
+    };
+}
+
 macro_rules! constify_imm3 {
     ($imm8:expr, $expand:ident) => {
         #[allow(overflowing_literals)]