[LoongArch] Add codegen support for fabs

[xen0n]

Trivial enough. Thanks!

llvm/lib/Target/LoongArch/LoongArchFloat32InstrInfo.td

 
 /// Float arithmetic operations
 
 def : PatFprFpr<fadd, FADD_S, FPR32>;
 def : PatFprFpr<fsub, FSUB_S, FPR32>;
 def : PatFprFpr<fmul, FMUL_S, FPR32>;
 def : PatFprFpr<fdiv, FDIV_S, FPR32>;
 def : PatFpr<fneg, FNEG_S, FPR32>;
+def : PatFpr<fabs, FABS_S, FPR32>;
 
 /// Setcc
 
 // Match non-signaling comparison
 
 // TODO: change setcc to any_fsetcc after call is supported because
 // we need to call llvm.experimental.constrained.fcmp.f32 in testcase.
 // See RISCV float-fcmp-strict.ll for reference.

llvm/lib/Target/LoongArch/LoongArchFloat64InstrInfo.td

 
 /// Float arithmetic operations
 
 def : PatFprFpr<fadd, FADD_D, FPR64>;
 def : PatFprFpr<fsub, FSUB_D, FPR64>;
 def : PatFprFpr<fmul, FMUL_D, FPR64>;
 def : PatFprFpr<fdiv, FDIV_D, FPR64>;
 def : PatFpr<fneg, FNEG_D, FPR64>;
+def : PatFpr<fabs, FABS_D, FPR64>;
 
 /// Setcc
 
 // Match non-signaling comparison
 
 // TODO: Change setcc to any_fsetcc after call is supported because
 // we need to call llvm.experimental.constrained.fcmp.f64 in testcase.
 // See RISCV float-fcmp-strict.ll for reference.

llvm/test/CodeGen/LoongArch/fabs.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc --mtriple=loongarch32 --mattr=+f,-d < %s | FileCheck %s --check-prefix=LA32F
+; RUN: llc --mtriple=loongarch32 --mattr=+d < %s | FileCheck %s --check-prefix=LA32D
+; RUN: llc --mtriple=loongarch64 --mattr=+f,-d < %s | FileCheck %s --check-prefix=LA64F
+; RUN: llc --mtriple=loongarch64 --mattr=+d < %s | FileCheck %s --check-prefix=LA64D
+
+declare float @llvm.fabs.f32(float)
+declare double @llvm.fabs.f64(double)
+
+define float @fabs_f32(float %a) nounwind {
+; LA32F-LABEL: fabs_f32:
+; LA32F:       # %bb.0:
+; LA32F-NEXT:    fabs.s $fa0, $fa0
+; LA32F-NEXT:    ret
+;
+; LA32D-LABEL: fabs_f32:
+; LA32D:       # %bb.0:
+; LA32D-NEXT:    fabs.s $fa0, $fa0
+; LA32D-NEXT:    ret
+;
+; LA64F-LABEL: fabs_f32:
+; LA64F:       # %bb.0:
+; LA64F-NEXT:    fabs.s $fa0, $fa0
+; LA64F-NEXT:    ret
+;
+; LA64D-LABEL: fabs_f32:
+; LA64D:       # %bb.0:
+; LA64D-NEXT:    fabs.s $fa0, $fa0
+; LA64D-NEXT:    ret
+  %1 = call float @llvm.fabs.f32(float %a)
+  ret float %1
+}
+
+define double @fabs_f64(double %a) nounwind {
+; LA32F-LABEL: fabs_f64:
+; LA32F:       # %bb.0:
+; LA32F-NEXT:    bstrpick.w $a1, $a1, 30, 0
+; LA32F-NEXT:    ret
+;
+; LA32D-LABEL: fabs_f64:
+; LA32D:       # %bb.0:
+; LA32D-NEXT:    fabs.d $fa0, $fa0
+; LA32D-NEXT:    ret
+;
+; LA64F-LABEL: fabs_f64:
+; LA64F:       # %bb.0:
+; LA64F-NEXT:    bstrpick.d $a0, $a0, 62, 0
+; LA64F-NEXT:    ret
+;
+; LA64D-LABEL: fabs_f64:
+; LA64D:       # %bb.0:
+; LA64D-NEXT:    fabs.d $fa0, $fa0
+; LA64D-NEXT:    ret
+  %1 = call double @llvm.fabs.f64(double %a)
+  ret double %1
+}