[clang] [llvm] [HLSL][DXIL] Implement `refract` intrinsic (PR #136026)

[Farzon Lotfi via cfe-commits]

================
@@ -0,0 +1,356 @@
+// 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_refract_halfDhDhDh(
+// CHECK-SAME: half noundef nofpclass(nan inf) [[I:%.*]], half noundef nofpclass(nan inf) [[N:%.*]], half noundef nofpclass(nan inf) [[ETA:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  [[ENTRY:.*:]]
+// CHECK-NEXT:    [[MUL_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[ETA]], [[ETA]]
+// CHECK-NEXT:    [[TMP0:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[N]], [[I]]
+// CHECK-NEXT:    [[TMP1:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[TMP0]], [[TMP0]]
+// CHECK-NEXT:    [[SUB1_I:%.*]] = fsub reassoc nnan ninf nsz arcp afn half 0xH3C00, [[TMP1]]
+// CHECK-NEXT:    [[MUL4_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[MUL_I]], [[SUB1_I]]
+// CHECK-NEXT:    [[SUB5_I:%.*]] = fsub reassoc nnan ninf nsz arcp afn half 0xH3C00, [[MUL4_I]]
+// CHECK-NEXT:    [[CMP_I:%.*]] = fcmp reassoc nnan ninf nsz arcp afn olt half [[SUB5_I]], 0xH0000
+// CHECK-NEXT:    br i1 [[CMP_I]], label %_ZN4hlsl8__detail12refract_implIDhEET_S2_S2_S2_.exit, label %if.else.i
+// CHECK:  if.else.i:                                        ; preds = %entry
+// CHECK-NEXT:    [[MUL6_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[ETA]], [[I]]
+// CHECK-NEXT:    [[MUL7_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[N]], [[I]]
+// CHECK-NEXT:    [[MUL8_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[MUL7_I]], [[ETA]]
+// CHECK-NEXT:    [[TMP2:%.*]] = tail call reassoc nnan ninf nsz arcp afn half @llvm.sqrt.f16(half [[SUB5_I]])
+// CHECK-NEXT:    [[ADD_I:%.*]] = fadd reassoc nnan ninf nsz arcp afn half [[TMP2]], [[MUL8_I]]
+// CHECK-NEXT:    [[MUL9_I:%.*]] = fmul reassoc nnan ninf nsz arcp afn half [[ADD_I]], [[N]]
+// CHECK-NEXT:    [[SUB10_I:%.*]] = fsub reassoc nnan ninf nsz arcp afn half [[MUL6_I]], [[MUL9_I]]
+// CHECK-NEXT:    br label %_ZN4hlsl8__detail12refract_implIDhEET_S2_S2_S2_.exit
+// CHECK:  _ZN4hlsl8__detail12refract_implIDhEET_S2_S2_S2_.exit: ; preds = %entry, %if.else.i
+// CHECK-NEXT:    [[RETVAL_0_I:%.*]] = phi nsz half [ [[SUB10_I]], %if.else.i ], [ 0xH0000, %entry ]
+// CHECK-NEXT:    ret half [[RETVAL_0_I]]
+//
+//
+// SPVCHECK-LABEL: define spir_func noundef nofpclass(nan inf) half @_Z17test_refract_halfDhDhDh(
+// SPVCHECK-SAME: half noundef nofpclass(nan inf) [[I:%.*]], half noundef nofpclass(nan inf) [[N:%.*]], half noundef nofpclass(nan inf) [[ETA:%.*]]) local_unnamed_addr #[[ATTR0:[0-9]+]] 
+// SPVCHECK-NEXT:  [[ENTRY:.*:]]
----------------
farzonl wrote:

the SPIRV and CHECK lines are the same we can combine these by adding a third check that covers the cases where the runlines are the same. There should be examples of this.

https://github.com/llvm/llvm-project/pull/136026