[clang] [HLSL] Implement support for HLSL intrinsic - select (PR #107129)

[Chris B via cfe-commits]

================
@@ -0,0 +1,76 @@
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes \
+// RUN:   -o - | FileCheck %s --check-prefixes=CHECK
+
+// CHECK: %hlsl.select = select i1
+// CHECK: ret i32 %hlsl.select
+int test_select_bool_int(bool cond0, int tVal, int fVal) { return select<int>(cond0, tVal, fVal); }
+
+// CHECK: %hlsl.select = select i1
+// CHECK: ret <2 x i32> %hlsl.select
+vector<int,2> test_select_bool_vector(bool cond0, vector<int, 2> tVal, vector<int, 2> fVal) { return select<vector<int,2> >(cond0, tVal, fVal); }
+
+// CHECK: %4 = extractelement <1 x i1> %extractvec, i32 0
+// CHECK: %5 = extractelement <1 x i32> %2, i32 0
+// CHECK: %6 = extractelement <1 x i32> %3, i32 0
+// CHECK: %7 = select i1 %4, i32 %5, i32 %6
+// CHECK: %8 = insertelement <1 x i32> poison, i32 %7, i32 0
+// CHECK: ret <1 x i32> %8
+vector<int,1> test_select_vector_1(vector<bool,1> cond0, vector<int,1> tVals, vector<int,1> fVals) { return select<int,1>(cond0, tVals, fVals); }
+
+// CHECK: %4 = extractelement <2 x i1> %extractvec, i32 0
+// CHECK: %5 = extractelement <2 x i32> %2, i32 0
+// CHECK: %6 = extractelement <2 x i32> %3, i32 0
+// CHECK: %7 = select i1 %4, i32 %5, i32 %6
+// CHECK: %8 = insertelement <2 x i32> poison, i32 %7, i32 0
+// CHECK: %9 = extractelement <2 x i1> %extractvec, i32 1
+// CHECK: %10 = extractelement <2 x i32> %2, i32 1
+// CHECK: %11 = extractelement <2 x i32> %3, i32 1
+// CHECK: %12 = select i1 %9, i32 %10, i32 %11
+// CHECK: %13 = insertelement <2 x i32> %8, i32 %12, i32 1
+// CHECK: ret <2 x i32> %13
+vector<int,2> test_select_vector_2(vector<bool, 2> cond0, vector<int, 2> tVals, vector<int, 2> fVals) { return select<int,2>(cond0, tVals, fVals); }
+
+// CHECK: %4 = extractelement <3 x i1> %extractvec, i32 0
+// CHECK: %5 = extractelement <3 x i32> %2, i32 0
+// CHECK: %6 = extractelement <3 x i32> %3, i32 0
+// CHECK: %7 = select i1 %4, i32 %5, i32 %6
+// CHECK: %8 = insertelement <3 x i32> poison, i32 %7, i32 0
+// CHECK: %9 = extractelement <3 x i1> %extractvec, i32 1
+// CHECK: %10 = extractelement <3 x i32> %2, i32 1
+// CHECK: %11 = extractelement <3 x i32> %3, i32 1
+// CHECK: %12 = select i1 %9, i32 %10, i32 %11
+// CHECK: %13 = insertelement <3 x i32> %8, i32 %12, i32 1
+// CHECK: %14 = extractelement <3 x i1> %extractvec, i32 2
+// CHECK: %15 = extractelement <3 x i32> %2, i32 2
+// CHECK: %16 = extractelement <3 x i32> %3, i32 2
+// CHECK: %17 = select i1 %14, i32 %15, i32 %16
+// CHECK: %18 = insertelement <3 x i32> %13, i32 %17, i32 2
+// CHECK: ret <3 x i32> %18
+vector<int,3> test_select_vector_3(vector<bool, 3> cond0, vector<int, 3> tVals, vector<int, 3> fVals) { return select<int,3>(cond0, tVals, fVals); }
+
+// CHECK: %4 = extractelement <4 x i1> %extractvec, i32 0
+// CHECK: %5 = extractelement <4 x i32> %2, i32 0
+// CHECK: %6 = extractelement <4 x i32> %3, i32 0
+// CHECK: %7 = select i1 %4, i32 %5, i32 %6
+// CHECK: %8 = insertelement <4 x i32> poison, i32 %7, i32 0
+// CHECK: %9 = extractelement <4 x i1> %extractvec, i32 1
+// CHECK: %10 = extractelement <4 x i32> %2, i32 1
+// CHECK: %11 = extractelement <4 x i32> %3, i32 1
+// CHECK: %12 = select i1 %9, i32 %10, i32 %11
+// CHECK: %13 = insertelement <4 x i32> %8, i32 %12, i32 1
+// CHECK: %14 = extractelement <4 x i1> %extractvec, i32 2
+// CHECK: %15 = extractelement <4 x i32> %2, i32 2
+// CHECK: %16 = extractelement <4 x i32> %3, i32 2
+// CHECK: %17 = select i1 %14, i32 %15, i32 %16
+// CHECK: %18 = insertelement <4 x i32> %13, i32 %17, i32 2
+// CHECK: %19 = extractelement <4 x i1> %extractvec, i32 3
+// CHECK: %20 = extractelement <4 x i32> %2, i32 3
+// CHECK: %21 = extractelement <4 x i32> %3, i32 3
+// CHECK: %22 = select i1 %19, i32 %20, i32 %21
+// CHECK: %23 = insertelement <4 x i32> %18, i32 %22, i32 3
+// CHECK: ret <4 x i32> %23
+vector<int,4> test_select_vector_4(vector<bool, 4> cond0, vector<int, 4> tVals, vector<int, 4> fVals) { return select<int,4>(cond0, tVals, fVals); }
----------------
llvm-beanz wrote:

Can you add some tests that verify that the template parameter gets correctly inferred? Some test cases like:

```
select(bool4, int4, int4);
select(bool, struct S, struct S);
```

https://github.com/llvm/llvm-project/pull/107129