[llvm] [DirectX] Add trig intrinsics and link them with DXIL backend (PR #95968)

[Helena Kotas via llvm-commits]

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+; RUN: opt -S -dxil-op-lower < %s | FileCheck %s
+
+; Make sure dxil operation function calls for acos are generated for float and half.
+
+define noundef float @tan_float(float noundef %a) {
+entry:
+; CHECK:call float @dx.op.unary.f32(i32 15, float %{{.*}})
+  %elt.acos = call float @llvm.acos.f32(float %a)
+  ret float %elt.acos
+}
+
+define noundef half @tan_half(half noundef %a) {
+entry:
+; CHECK:call half @dx.op.unary.f16(i32 15, half %{{.*}})
+  %elt.acos = call half @llvm.acos.f16(half %a)
+  ret half %elt.acos
+}
+
+declare half @llvm.acos.f16(half)
+declare float @llvm.acos.f32(float)
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hekota wrote:

Should we have test cases with vectors too? We are not consistent - some intrinsics have vector tests in this folder and some do not.

https://github.com/llvm/llvm-project/pull/95968