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

[Deric C. via cfe-commits]

================
@@ -22,56 +22,136 @@
 //
 // 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:   -DFNATTRS="spir_func noundef nofpclass(nan inf)" -DTYPE=half
+// RUN:   -emit-llvm -o - | FileCheck %s \
+// RUN:   -DTYPE=half --check-prefixes=CHECK,SPVCHECK
 
 //
 // ---------- 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
+// RUN:   -DTYPE=float --check-prefixes=CHECK,SPVCHECK
 
 
 
-// CHECK: define [[FNATTRS]] [[TYPE]] @
-// CHECK: %fmod = frem reassoc nnan ninf nsz arcp afn [[TYPE]]
-// CHECK: ret [[TYPE]] %fmod
+// CHECK-LABEL: test_fmod_half
+// DXCHECK: %div1.i = fdiv reassoc nnan ninf nsz arcp afn [[TYPE]] [[X:%.*]], [[Y:%.*]]
+// DXCHECK: %fneg.i = fneg reassoc nnan ninf nsz arcp afn [[TYPE]] [[DIV1_I:%.*]]
+// DXCHECK: %cmp.i = fcmp reassoc nnan ninf nsz arcp afn oge [[TYPE]] [[DIV1_I_2:%.*]], %fneg.i
+// DXNATIVE_HALF: %elt.abs.i = call reassoc nnan ninf nsz arcp afn [[TYPE]] @llvm.fabs.f16([[TYPE]] [[DIV1_I_3:%.*]])
+// DXNO_HALF: %elt.abs.i = call reassoc nnan ninf nsz arcp afn [[TYPE]] @llvm.fabs.f32([[TYPE]] [[DIV1_I_3:%.*]])
+// DXNATIVE_HALF: %hlsl.frac.i = call reassoc nnan ninf nsz arcp afn [[TYPE]] @llvm.dx.frac.f16([[TYPE]] %elt.abs.i)
+// DXNO_HALF: %hlsl.frac.i = call reassoc nnan ninf nsz arcp afn [[TYPE]] @llvm.dx.frac.f32([[TYPE]] %elt.abs.i)
+// DXCHECK: %fneg2.i = fneg reassoc nnan ninf nsz arcp afn [[TYPE]] [[HLSL_FRAC_I:%.*]]
+// DXCHECK: %hlsl.select.i = select reassoc nnan ninf nsz arcp afn i1 [[CMP_I:%.*]], [[TYPE]] [[HLSL_FRAC_I_2:%.*]], [[TYPE]] %fneg2.i
+// DXCHECK: %mul.i = fmul reassoc nnan ninf nsz arcp afn [[TYPE]] %hlsl.select.i, [[Y_2:%.*]]
+// DXCHECK: ret [[TYPE]] %mul.i
+// SPVCHECK: %fmod.i = frem reassoc nnan ninf nsz arcp afn [[TYPE]] [[X:%.*]], [[Y:%.*]]
+// SPVCHECK: ret [[TYPE]] %fmod.i
 half test_fmod_half(half p0, half p1) { return fmod(p0, p1); }
 
-// CHECK: define [[FNATTRS]] <2 x [[TYPE]]> @
-// CHECK: %fmod = frem reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]>
-// CHECK: ret <2 x [[TYPE]]> %fmod
+// CHECK-LABEL: test_fmod_half2
+// DXCHECK: %div1.i = fdiv reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> [[X:%.*]], [[Y:%.*]]
+// DXCHECK: %fneg.i = fneg reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> [[DIV1_I:%.*]]
+// DXCHECK: %cmp.i = fcmp reassoc nnan ninf nsz arcp afn oge <2 x [[TYPE]]> [[DIV1_I_2:%.*]], %fneg.i
+// DXNATIVE_HALF: %elt.abs.i = call reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> @llvm.fabs.v2f16(<2 x [[TYPE]]> [[DIV1_I_3:%.*]])
+// DXNO_HALF: %elt.abs.i = call reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> @llvm.fabs.v2f32(<2 x [[TYPE]]> [[DIV1_I_3:%.*]])
+// DXNATIVE_HALF: %hlsl.frac.i = call reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> @llvm.dx.frac.v2f16(<2 x [[TYPE]]> %elt.abs.i)
+// DXNO_HALF: %hlsl.frac.i = call reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> @llvm.dx.frac.v2f32(<2 x [[TYPE]]> %elt.abs.i)
+// DXCHECK: %fneg2.i = fneg reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> [[HLSL_FRAC_I:%.*]]
+// DXCHECK: %hlsl.select.i = select reassoc nnan ninf nsz arcp afn <2 x i1> [[CMP_I:%.*]], <2 x [[TYPE]]> [[HLSL_FRAC_I_2:%.*]], <2 x [[TYPE]]> %fneg2.i
+// DXCHECK: %mul.i = fmul reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> %hlsl.select.i, [[Y_2:%.*]]
+// DXCHECK: ret <2 x [[TYPE]]> %mul.i
+// SPVCHECK: %fmod.i = frem reassoc nnan ninf nsz arcp afn <2 x [[TYPE]]> [[X:%.*]], [[Y:%.*]]
+// SPVCHECK: ret <2 x [[TYPE]]> %fmod.i
 half2 test_fmod_half2(half2 p0, half2 p1) { return fmod(p0, p1); }
 
-// CHECK: define [[FNATTRS]] <3 x [[TYPE]]> @
-// CHECK: %fmod = frem reassoc nnan ninf nsz arcp afn <3 x [[TYPE]]>
-// CHECK: ret <3 x [[TYPE]]> %fmod
+// CHECK-LABEL: test_fmod_half3
+// DXCHECK: %div1.i = fdiv reassoc nnan ninf nsz arcp afn <3 x [[TYPE]]> [[X:%.*]], [[Y:%.*]]
+// DXCHECK: %fneg.i = fneg reassoc nnan ninf nsz arcp afn <3 x [[TYPE]]> [[DIV1_I:%.*]]
----------------
Icohedron wrote:

It's always better to include as many or all the instructions as you can that participate in the computation of the result.
In this case, since there are many instructions, you may want to use the python script [`llvm/utils/update_cc_test_checks.py`](https://github.com/llvm/llvm-project/blob/main/llvm/utils/update_cc_test_checks.py) to generate the `*CHECK` lines for you:
`python3 llvm/utils/update_cc_test_checks.py --version 5 --clang=/path/to/your/built/clang clang/test/CodeGenHLSL/builtins/fmod.hlsl`

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