[clang] Implement the `fmod` intrinsic (PR #130320)

[Kaitlin Peng via cfe-commits]

================
@@ -22,56 +22,144 @@
 //
 // RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
 // RUN:   spirv-unknown-vulkan-compute %s -fnative-half-type \
-// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s \
+// RUN:   -emit-llvm -o - | FileCheck %s \
 // RUN:   -DFNATTRS="spir_func noundef nofpclass(nan inf)" -DTYPE=half
 
 //
 // ---------- No Native Half support test -----------
 //
 // RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
-// RUN:   spirv-unknown-vulkan-compute %s -emit-llvm -disable-llvm-passes \
+// RUN:   spirv-unknown-vulkan-compute %s -emit-llvm \
 // RUN:   -o - | FileCheck %s \
 // RUN:   -DFNATTRS="spir_func noundef nofpclass(nan inf)" -DTYPE=float
 
 
 
+// DXCHECK: define [[FNATTRS]] [[TYPE]] @
+// DXCHECK: %div1.i = fdiv reassoc nnan ninf nsz arcp afn [[TYPE]]
----------------
kmpeng wrote:

`%div1.i` is used as an operand in a lot following instructions and a different register is used for each instruction (`%7`, `%8`, `%9`). Would it be better practice to replace all of these register names with `[[DIV1_I:%.*]]` so it's clear they're all `%div1.i`, or would it be better to replace the first one with `[[DIV1_I:%.*]]`, the second with `[[DIV1_I_2:%.*]]`, etc.?

https://github.com/llvm/llvm-project/pull/130320