[LLVM][NVPTX] Add support for div.full instruction (#116482)

This commit adds NVPTX support for div.full PTX instruction with test
under div.ll. [For more information, see PTX
ISA](https://docs.nvidia.com/cuda/parallel-thread-execution/#floating-point-instructions-div)

Author: schwarzschild-radius

llvm/include/llvm/IR/IntrinsicsNVVM.td

@@ -820,6 +820,13 @@ let TargetPrefix = "nvvm" in {
       DefaultAttrsIntrinsic<[llvm_double_ty], [llvm_double_ty, llvm_double_ty],
         [IntrNoMem]>;
 
+  def int_nvvm_div_full : ClangBuiltin<"__nvvm_div_full">,
+      DefaultAttrsIntrinsic<[llvm_float_ty], [llvm_float_ty, llvm_float_ty],
+        [IntrNoMem]>;
+  def int_nvvm_div_full_ftz : ClangBuiltin<"__nvvm_div_full_ftz">,
+      DefaultAttrsIntrinsic<[llvm_float_ty], [llvm_float_ty, llvm_float_ty],
+        [IntrNoMem]>;
+
 //
 // Sad
 //

llvm/lib/Target/NVPTX/NVPTXIntrinsics.td

@@ -1096,6 +1096,18 @@ def INT_NVVM_DIV_RM_D : F_MATH_2<"div.rm.f64 \t$dst, $src0, $src1;",
 def INT_NVVM_DIV_RP_D : F_MATH_2<"div.rp.f64 \t$dst, $src0, $src1;",
   Float64Regs, Float64Regs, Float64Regs, int_nvvm_div_rp_d>;
 
+def : Pat<(int_nvvm_div_full Float32Regs:$a, Float32Regs:$b),
+          (FDIV32rr Float32Regs:$a, Float32Regs:$b)>;
+
+def : Pat<(int_nvvm_div_full Float32Regs:$a, fpimm:$b),
+          (FDIV32ri Float32Regs:$a, f32imm:$b)>;
+
+def : Pat<(int_nvvm_div_full_ftz Float32Regs:$a, Float32Regs:$b),
+          (FDIV32rr_ftz Float32Regs:$a, Float32Regs:$b)>;
+
+def : Pat<(int_nvvm_div_full_ftz Float32Regs:$a, fpimm:$b),
+          (FDIV32ri_ftz Float32Regs:$a, f32imm:$b)>;
+
 //
 // Sad
 //

llvm/test/CodeGen/NVPTX/div.ll

@@ -0,0 +1,26 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -march=nvptx64 | FileCheck %s
+; RUN: %if ptxas %{ llc < %s -march=nvptx64 | %ptxas-verify %}
+
+define float @div_full(float %a, float %b) {
+; CHECK-LABEL: div_full(
+; CHECK:       {
+; CHECK-NEXT:    .reg .f32 %f<9>;
+; CHECK-EMPTY:
+; CHECK-NEXT:  // %bb.0:
+; CHECK-NEXT:    ld.param.f32 %f1, [div_full_param_0];
+; CHECK-NEXT:    ld.param.f32 %f2, [div_full_param_1];
+; CHECK-NEXT:    div.full.f32 %f3, %f1, %f2;
+; CHECK-NEXT:    mov.f32 %f4, 0f40400000;
+; CHECK-NEXT:    div.full.f32 %f5, %f3, %f4;
+; CHECK-NEXT:    div.full.ftz.f32 %f6, %f5, %f2;
+; CHECK-NEXT:    mov.f32 %f7, 0f40800000;
+; CHECK-NEXT:    div.full.ftz.f32 %f8, %f6, %f7;
+; CHECK-NEXT:    st.param.f32 [func_retval0], %f8;
+; CHECK-NEXT:    ret;
+  %1 = call float @llvm.nvvm.div.full(float %a, float %b)
+  %2 = call float @llvm.nvvm.div.full(float %1, float 3.0)
+  %3 = call float @llvm.nvvm.div.full.ftz(float %2, float %b)
+  %4 = call float @llvm.nvvm.div.full.ftz(float %3, float 4.0)
+  ret float %4
+}