[clang] [HLSL] Implementation of the fmod intrinsic (PR #108849)

[Farzon Lotfi via cfe-commits]

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@@ -0,0 +1,38 @@
+
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.6-library %s -fnative-half-type -emit-llvm-only -disable-llvm-passes -verify -verify-ignore-unexpected
+
+float test_too_few_arg() {
+  return __builtin_elementwise_fmod();
+  // expected-error at -1 {{too few arguments to function call, expected 2, have 0}}
+}
+
+float2 test_too_many_arg(float2 p0, float2 p1, float2 p3) {
+  return __builtin_elementwise_fmod(p0, p1, p3);
+  // expected-error at -1 {{too many arguments to function call, expected 2, have 3}}
+}
+
+float builtin_bool_to_float_type_promotion(bool p1, bool p2) {
+  return __builtin_elementwise_fmod(p1, p2);
+  // expected-error at -1 {{passing 'bool' to parameter of incompatible type 'float'}}
+}
+
+float builtin_fmod_int_to_float_promotion(int p1, int p2) {
+  return __builtin_elementwise_fmod(p1, p2);
+  // expected-error at -1 {{passing 'int' to parameter of incompatible type 'float'}}
+}
+
+float2 builtin_fmod_int2_to_float2_promotion(int2 p1, int2 p2) {
+  return __builtin_elementwise_fmod(p1, p2);
+  // expected-error at -1 {{passing 'int2' (aka 'vector<int, 2>') to parameter of incompatible type '__attribute__((__vector_size__(2 * sizeof(float)))) float' (vector of 2 'float' values)}}
+}
+
+// builtins are variadic functions and so are subject to DefaultVariadicArgumentPromotion
+half builtin_fmod_half_scalar (half p0, half p1) {
----------------
farzonl wrote:

This doesn’t look right.  Which makes me think we shouldn’t capture this implementation detail if  fmod hlsl api is working fine with float/half. You are passing half/float in these two cases. For cases like this future folks are going to want to change/fix this test case. To avoid the confusion caused by variadic argument promotion we should care more what the fmod sema error checking returns.

https://github.com/llvm/llvm-project/pull/108849