Add more SIMD math.h intrinsics

LLVM supports many functions from math.h in its IR. Many of these have
single-instruction variants on various platforms. So, let's add them so
std::arch can use them.

Yes, exact comparison is intentional: rounding must always return a
valid integer-equal value, except for inf/NAN.

compiler/rustc_codegen_cranelift/src/intrinsics/simd.rs

@@ -277,5 +277,7 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
         // simd_select
         // simd_rem
         // simd_neg
+        // simd_trunc
+        // simd_floor
     }
 }

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -1057,8 +1057,10 @@ fn generic_simd_intrinsic(
             sym::simd_fsin => ("sin", bx.type_func(&[vec_ty], vec_ty)),
             sym::simd_fcos => ("cos", bx.type_func(&[vec_ty], vec_ty)),
             sym::simd_fabs => ("fabs", bx.type_func(&[vec_ty], vec_ty)),
-            sym::simd_floor => ("floor", bx.type_func(&[vec_ty], vec_ty)),
             sym::simd_ceil => ("ceil", bx.type_func(&[vec_ty], vec_ty)),
+            sym::simd_floor => ("floor", bx.type_func(&[vec_ty], vec_ty)),
+            sym::simd_round => ("round", bx.type_func(&[vec_ty], vec_ty)),
+            sym::simd_trunc => ("trunc", bx.type_func(&[vec_ty], vec_ty)),
             sym::simd_fexp => ("exp", bx.type_func(&[vec_ty], vec_ty)),
             sym::simd_fexp2 => ("exp2", bx.type_func(&[vec_ty], vec_ty)),
             sym::simd_flog10 => ("log10", bx.type_func(&[vec_ty], vec_ty)),
@@ -1083,8 +1085,10 @@ fn generic_simd_intrinsic(
             | sym::simd_fsin
             | sym::simd_fcos
             | sym::simd_fabs
-            | sym::simd_floor
             | sym::simd_ceil
+            | sym::simd_floor
+            | sym::simd_round
+            | sym::simd_trunc
             | sym::simd_fexp
             | sym::simd_fexp2
             | sym::simd_flog10

compiler/rustc_span/src/symbol.rs

@@ -1101,6 +1101,7 @@ symbols! {
         simd_reduce_or,
         simd_reduce_xor,
         simd_rem,
+        simd_round,
         simd_saturating_add,
         simd_saturating_sub,
         simd_scatter,
@@ -1109,6 +1110,7 @@ symbols! {
         simd_shl,
         simd_shr,
         simd_sub,
+        simd_trunc,
         simd_xor,
         since,
         sinf32,

compiler/rustc_typeck/src/check/intrinsic.rs

@@ -407,8 +407,8 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         | sym::simd_fpow
         | sym::simd_saturating_add
         | sym::simd_saturating_sub => (1, vec![param(0), param(0)], param(0)),
-        sym::simd_neg => (1, vec![param(0)], param(0)),
+        sym::simd_neg
-        sym::simd_fsqrt
+        | sym::simd_fsqrt
         | sym::simd_fsin
         | sym::simd_fcos
         | sym::simd_fexp
@@ -417,8 +417,10 @@ pub fn check_platform_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>)
         | sym::simd_flog10
         | sym::simd_flog
         | sym::simd_fabs
+        | sym::simd_ceil
         | sym::simd_floor
-        | sym::simd_ceil => (1, vec![param(0)], param(0)),
+        | sym::simd_round
+        | sym::simd_trunc => (1, vec![param(0)], param(0)),
         sym::simd_fpowi => (1, vec![param(0), tcx.types.i32], param(0)),
         sym::simd_fma => (1, vec![param(0), param(0), param(0)], param(0)),
         sym::simd_gather => (3, vec![param(0), param(1), param(2)], param(0)),

src/test/ui/simd/simd-intrinsic-float-math.rs

@@ -20,16 +20,20 @@ extern "platform-intrinsic" {
     fn simd_fabs<T>(x: T) -> T;
     fn simd_fsin<T>(x: T) -> T;
     fn simd_fcos<T>(x: T) -> T;
-    fn simd_ceil<T>(x: T) -> T;
     fn simd_fexp<T>(x: T) -> T;
     fn simd_fexp2<T>(x: T) -> T;
-    fn simd_floor<T>(x: T) -> T;
     fn simd_fma<T>(x: T, y: T, z: T) -> T;
     fn simd_flog<T>(x: T) -> T;
     fn simd_flog10<T>(x: T) -> T;
     fn simd_flog2<T>(x: T) -> T;
     fn simd_fpow<T>(x: T, y: T) -> T;
     fn simd_fpowi<T>(x: T, y: i32) -> T;
+
+    // rounding functions
+    fn simd_ceil<T>(x: T) -> T;
+    fn simd_floor<T>(x: T) -> T;
+    fn simd_round<T>(x: T) -> T;
+    fn simd_trunc<T>(x: T) -> T;
 }
 
 macro_rules! assert_approx_eq_f32 {
@@ -64,18 +68,12 @@ fn main() {
         let r = simd_fcos(z);
         assert_approx_eq!(x, r);
 
-        let r = simd_ceil(h);
-        assert_approx_eq!(x, r);
-
         let r = simd_fexp(z);
         assert_approx_eq!(x, r);
 
         let r = simd_fexp2(z);
         assert_approx_eq!(x, r);
 
-        let r = simd_floor(h);
-        assert_approx_eq!(z, r);
-
         let r = simd_fma(x, h, h);
         assert_approx_eq!(x, r);
 
@@ -99,5 +97,18 @@ fn main() {
 
         let r = simd_fsin(z);
         assert_approx_eq!(z, r);
+
+        // rounding functions
+        let r = simd_floor(h);
+        assert_eq!(z, r);
+
+        let r = simd_ceil(h);
+        assert_eq!(x, r);
+
+        let r = simd_round(h);
+        assert_eq!(x, r);
+
+        let r = simd_trunc(h);
+        assert_eq!(z, r);
     }
 }