[clang] [llvm] [HLSL] Implement the `reflect` HLSL function (PR #122992)

[Farzon Lotfi via llvm-commits]

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@@ -0,0 +1,195 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
+// RUN: %clang_cc1 -finclude-default-header -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s -fnative-half-type \
+// RUN:   -emit-llvm -O1 -o - | FileCheck %s
+// RUN: %clang_cc1 -finclude-default-header -triple \
+// RUN:   spirv-unknown-vulkan-compute %s -fnative-half-type \
+// RUN:   -emit-llvm -O1 -o - | FileCheck %s --check-prefix=SPVCHECK
+
+// CHECK-LABEL: define noundef nofpclass(nan inf) half @_Z17test_reflect_halfDhDh(
+// CHECK-SAME: half noundef nofpclass(nan inf) [[I:%.*]], half noundef nofpclass(nan inf) [[N:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[MUL_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[I]], 0xH4000
+// CHECK-NEXT:    [[TMP0:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[N]], [[N]]
+// CHECK-NEXT:    [[MUL2_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[TMP0]], [[MUL_I]]
+// CHECK-NEXT:    [[SUB_I:%.*]] = fsub reassoc nnan ninf nsz arcp afn half [[I]], [[MUL2_I]]
+// CHECK-NEXT:    ret half [[SUB_I]]
+//
+// SPVCHECK-LABEL: define spir_func noundef nofpclass(nan inf) half @_Z17test_reflect_halfDhDh(
+// SPVCHECK-SAME: half noundef nofpclass(nan inf) [[I:%.*]], half noundef nofpclass(nan inf) [[N:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
+// SPVCHECK-NEXT:  [[ENTRY:.*:]]
+// SPVCHECK-NEXT:    [[MUL_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[I]], 0xH4000
+// SPVCHECK-NEXT:    [[TMP0:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[N]], [[N]]
+// SPVCHECK-NEXT:    [[MUL2_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[TMP0]], [[MUL_I]]
+// SPVCHECK-NEXT:    [[SUB_I:%.*]] = fsub reassoc nnan ninf nsz arcp afn half [[I]], [[MUL2_I]]
+// SPVCHECK-NEXT:    ret half [[SUB_I]]
+//
+half test_reflect_half(half I, half N) {
+    return reflect(I, N);
+}
+
+// CHECK-LABEL: define noundef nofpclass(nan inf) <2 x half> @_Z18test_reflect_half2Dv2_DhS_(
+// CHECK-SAME: <2 x half> noundef nofpclass(nan inf) [[I:%.*]], <2 x half> noundef nofpclass(nan inf) [[N:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[HLSL_DOT_I:%.*]] = tail call reassoc nnan ninf nsz arcp afn half @llvm.dx.fdot.v2f16(<2 x half> [[I]], <2 x half> [[N]])
+// CHECK-NEXT:    [[TMP0:%.*]] = extractelement <2 x half> [[I]], i64 0
+// CHECK-NEXT:    [[TMP1:%.*]] = extractelement <2 x half> [[N]], i64 0
+// CHECK-NEXT:    [[TMP2:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[TMP1]], 0xH4000
+// CHECK-NEXT:    [[TMP3:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[TMP2]], [[HLSL_DOT_I]]
+// CHECK-NEXT:    [[CAST_VTRUNC_I:%.*]] = fsub reassoc nnan ninf nsz arcp afn half [[TMP0]], [[TMP3]]
+// CHECK-NEXT:    [[SPLAT_SPLATINSERT:%.*]] = insertelement <2 x half> poison, half [[CAST_VTRUNC_I]], i64 0
+// CHECK-NEXT:    [[SPLAT_SPLAT:%.*]] = shufflevector <2 x half> [[SPLAT_SPLATINSERT]], <2 x half> poison, <2 x i32> zeroinitializer
+// CHECK-NEXT:    ret <2 x half> [[SPLAT_SPLAT]]
+//
+// SPVCHECK-LABEL: define spir_func noundef nofpclass(nan inf) <2 x half> @_Z18test_reflect_half2Dv2_DhS_(
+// SPVCHECK-SAME: <2 x half> noundef nofpclass(nan inf) [[I:%.*]], <2 x half> noundef nofpclass(nan inf) [[N:%.*]]) local_unnamed_addr #[[ATTR0]] {
+// SPVCHECK-NEXT:  [[ENTRY:.*:]]
+// SPVCHECK-NEXT:    [[SPV_REFLECT_I:%.*]] = tail call reassoc nnan ninf nsz arcp afn <2 x half> @llvm.spv.reflect.v2f16(<2 x half> [[I]], <2 x half> [[N]])
+// SPVCHECK-NEXT:    [[SPLAT_SPLAT:%.*]] = shufflevector <2 x half> [[SPV_REFLECT_I]], <2 x half> poison, <2 x i32> zeroinitializer
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farzonl wrote:

Why are we returning a vector splat?

https://github.com/llvm/llvm-project/pull/122992