[llvm] [DXIL] Add frac unary lowering (PR #83465)

[Farzon Lotfi via llvm-commits]

https://github.com/farzonl updated https://github.com/llvm/llvm-project/pull/83465

>From bbe4654eca674c68e42a9593fbbe4dde999f6715 Mon Sep 17 00:00:00 2001
From: Farzon Lotfi <farzon at farzon.org>
Date: Thu, 29 Feb 2024 14:06:49 -0500
Subject: [PATCH] [DXIL] Add frac unary lowering

---
 llvm/lib/Target/DirectX/DXIL.td   |  3 +++
 llvm/test/CodeGen/DirectX/frac.ll | 34 +++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 llvm/test/CodeGen/DirectX/frac.ll

diff --git a/llvm/lib/Target/DirectX/DXIL.td b/llvm/lib/Target/DirectX/DXIL.td
index 67ef7986622092..40135709e167d9 100644
--- a/llvm/lib/Target/DirectX/DXIL.td
+++ b/llvm/lib/Target/DirectX/DXIL.td
@@ -218,6 +218,9 @@ class DXILOpMapping<int opCode, DXILOpClass opClass, Intrinsic intrinsic, string
 // Concrete definition of DXIL Operation mapping to corresponding LLVM intrinsic
 def Sin  : DXILOpMapping<13, unary, int_sin,
                          "Returns sine(theta) for theta in radians.">;
+def Frac : DXILOpMapping<22, unary, int_dx_frac,
+                         "Returns a fraction from 0 to 1 that represents the "
+                         "decimal part of the input.">;
 def UMax : DXILOpMapping<39, binary, int_umax,
                          "Unsigned integer maximum. UMax(a,b) = a > b ? a : b">;
 def ThreadId : DXILOpMapping<93, threadId, int_dx_thread_id,
diff --git a/llvm/test/CodeGen/DirectX/frac.ll b/llvm/test/CodeGen/DirectX/frac.ll
new file mode 100644
index 00000000000000..ab605ed6084aa4
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/frac.ll
@@ -0,0 +1,34 @@
+; RUN: opt -S -dxil-op-lower < %s | FileCheck %s
+
+; Make sure dxil operation function calls for frac are generated for float and half.
+; CHECK:call float @dx.op.unary.f32(i32 22, float %{{.*}})
+; CHECK:call half @dx.op.unary.f16(i32 22, half %{{.*}})
+
+target datalayout = "e-m:e-p:32:32-i1:32-i8:8-i16:16-i32:32-i64:64-f16:16-f32:32-f64:64-n8:16:32:64"
+target triple = "dxil-pc-shadermodel6.7-library"
+
+; Function Attrs: noinline nounwind optnone
+define noundef float @frac_float(float noundef %a) #0 {
+entry:
+  %a.addr = alloca float, align 4
+  store float %a, ptr %a.addr, align 4
+  %0 = load float, ptr %a.addr, align 4
+  %dx.frac = call float @llvm.dx.frac.f32(float %0)
+  ret float %dx.frac
+}
+
+; Function Attrs: nocallback nofree nosync nounwind readnone speculatable willreturn
+declare float @llvm.dx.frac.f32(float) #1
+
+; Function Attrs: noinline nounwind optnone
+define noundef half @frac_half(half noundef %a) #0 {
+entry:
+  %a.addr = alloca half, align 2
+  store half %a, ptr %a.addr, align 2
+  %0 = load half, ptr %a.addr, align 2
+  %dx.frac = call half @llvm.dx.frac.f16(half %0)
+  ret half %dx.frac
+}
+
+; Function Attrs: nocallback nofree nosync nounwind readnone speculatable willreturn
+declare half @llvm.dx.frac.f16(half) #1