[LoongArch] Allow f16 codegen with expansion to libcalls (#94456)

The test case is adapted from llvm/test/CodeGen/RISCV/fp16-promote.ll,
because it covers some more IR patterns that ought to be common.

Fixes #93894

2 files changed, 334 insertions, 0 deletions

diff --git a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
index 32e02e3..9d7e463 100644
--- a/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
@@ -171,6 +171,8 @@ LoongArchTargetLowering::LoongArchTargetLowering(const TargetMachine &TM,
   // Set operations for 'F' feature.
 
   if (Subtarget.hasBasicF()) {
+    setLoadExtAction(ISD::EXTLOAD, MVT::f32, MVT::f16, Expand);
+    setTruncStoreAction(MVT::f32, MVT::f16, Expand);
     setCondCodeAction(FPCCToExpand, MVT::f32, Expand);
 
     setOperationAction(ISD::SELECT_CC, MVT::f32, Expand);
@@ -186,6 +188,8 @@ LoongArchTargetLowering::LoongArchTargetLowering(const TargetMachine &TM,
     setOperationAction(ISD::FSINCOS, MVT::f32, Expand);
     setOperationAction(ISD::FPOW, MVT::f32, Expand);
     setOperationAction(ISD::FREM, MVT::f32, Expand);
+    setOperationAction(ISD::FP16_TO_FP, MVT::f32, Expand);
+    setOperationAction(ISD::FP_TO_FP16, MVT::f32, Expand);
 
     if (Subtarget.is64Bit())
       setOperationAction(ISD::FRINT, MVT::f32, Legal);
@@ -202,7 +206,9 @@ LoongArchTargetLowering::LoongArchTargetLowering(const TargetMachine &TM,
   // Set operations for 'D' feature.
 
   if (Subtarget.hasBasicD()) {
+    setLoadExtAction(ISD::EXTLOAD, MVT::f64, MVT::f16, Expand);
     setLoadExtAction(ISD::EXTLOAD, MVT::f64, MVT::f32, Expand);
+    setTruncStoreAction(MVT::f64, MVT::f16, Expand);
     setTruncStoreAction(MVT::f64, MVT::f32, Expand);
     setCondCodeAction(FPCCToExpand, MVT::f64, Expand);
 
@@ -219,6 +225,8 @@ LoongArchTargetLowering::LoongArchTargetLowering(const TargetMachine &TM,
     setOperationAction(ISD::FSINCOS, MVT::f64, Expand);
     setOperationAction(ISD::FPOW, MVT::f64, Expand);
     setOperationAction(ISD::FREM, MVT::f64, Expand);
+    setOperationAction(ISD::FP16_TO_FP, MVT::f64, Expand);
+    setOperationAction(ISD::FP_TO_FP16, MVT::f64, Expand);
 
     if (Subtarget.is64Bit())
       setOperationAction(ISD::FRINT, MVT::f64, Legal);
diff --git a/llvm/test/CodeGen/LoongArch/fp16-promote.ll b/llvm/test/CodeGen/LoongArch/fp16-promote.ll
new file mode 100644
index 0000000..75f920b
--- /dev/null
+++ b/llvm/test/CodeGen/LoongArch/fp16-promote.ll
@@ -0,0 +1,326 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc --mtriple=loongarch32 --mattr=+d < %s | FileCheck %s --check-prefix=LA32
+; RUN: llc --mtriple=loongarch64 --mattr=+d < %s | FileCheck %s --check-prefix=LA64
+
+define void @test_load_store(ptr %p, ptr %q) nounwind {
+; LA32-LABEL: test_load_store:
+; LA32:       # %bb.0:
+; LA32-NEXT:    ld.h $a0, $a0, 0
+; LA32-NEXT:    st.h $a0, $a1, 0
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_load_store:
+; LA64:       # %bb.0:
+; LA64-NEXT:    ld.h $a0, $a0, 0
+; LA64-NEXT:    st.h $a0, $a1, 0
+; LA64-NEXT:    ret
+  %a = load half, ptr %p
+  store half %a, ptr %q
+  ret void
+}
+
+define float @test_fpextend_float(ptr %p) nounwind {
+; LA32-LABEL: test_fpextend_float:
+; LA32:       # %bb.0:
+; LA32-NEXT:    ld.hu $a0, $a0, 0
+; LA32-NEXT:    b %plt(__gnu_h2f_ieee)
+;
+; LA64-LABEL: test_fpextend_float:
+; LA64:       # %bb.0:
+; LA64-NEXT:    ld.hu $a0, $a0, 0
+; LA64-NEXT:    b %plt(__gnu_h2f_ieee)
+  %a = load half, ptr %p
+  %r = fpext half %a to float
+  ret float %r
+}
+
+define double @test_fpextend_double(ptr %p) nounwind {
+; LA32-LABEL: test_fpextend_double:
+; LA32:       # %bb.0:
+; LA32-NEXT:    addi.w $sp, $sp, -16
+; LA32-NEXT:    st.w $ra, $sp, 12 # 4-byte Folded Spill
+; LA32-NEXT:    ld.hu $a0, $a0, 0
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fcvt.d.s $fa0, $fa0
+; LA32-NEXT:    ld.w $ra, $sp, 12 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 16
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_fpextend_double:
+; LA64:       # %bb.0:
+; LA64-NEXT:    addi.d $sp, $sp, -16
+; LA64-NEXT:    st.d $ra, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    ld.hu $a0, $a0, 0
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fcvt.d.s $fa0, $fa0
+; LA64-NEXT:    ld.d $ra, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 16
+; LA64-NEXT:    ret
+  %a = load half, ptr %p
+  %r = fpext half %a to double
+  ret double %r
+}
+
+define void @test_fptrunc_float(float %f, ptr %p) nounwind {
+; LA32-LABEL: test_fptrunc_float:
+; LA32:       # %bb.0:
+; LA32-NEXT:    addi.w $sp, $sp, -16
+; LA32-NEXT:    st.w $ra, $sp, 12 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $fp, $sp, 8 # 4-byte Folded Spill
+; LA32-NEXT:    move $fp, $a0
+; LA32-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA32-NEXT:    st.h $a0, $fp, 0
+; LA32-NEXT:    ld.w $fp, $sp, 8 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $ra, $sp, 12 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 16
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_fptrunc_float:
+; LA64:       # %bb.0:
+; LA64-NEXT:    addi.d $sp, $sp, -16
+; LA64-NEXT:    st.d $ra, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $fp, $sp, 0 # 8-byte Folded Spill
+; LA64-NEXT:    move $fp, $a0
+; LA64-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA64-NEXT:    st.h $a0, $fp, 0
+; LA64-NEXT:    ld.d $fp, $sp, 0 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $ra, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 16
+; LA64-NEXT:    ret
+  %a = fptrunc float %f to half
+  store half %a, ptr %p
+  ret void
+}
+
+define void @test_fptrunc_double(double %d, ptr %p) nounwind {
+; LA32-LABEL: test_fptrunc_double:
+; LA32:       # %bb.0:
+; LA32-NEXT:    addi.w $sp, $sp, -16
+; LA32-NEXT:    st.w $ra, $sp, 12 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $fp, $sp, 8 # 4-byte Folded Spill
+; LA32-NEXT:    move $fp, $a0
+; LA32-NEXT:    bl %plt(__truncdfhf2)
+; LA32-NEXT:    st.h $a0, $fp, 0
+; LA32-NEXT:    ld.w $fp, $sp, 8 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $ra, $sp, 12 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 16
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_fptrunc_double:
+; LA64:       # %bb.0:
+; LA64-NEXT:    addi.d $sp, $sp, -16
+; LA64-NEXT:    st.d $ra, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $fp, $sp, 0 # 8-byte Folded Spill
+; LA64-NEXT:    move $fp, $a0
+; LA64-NEXT:    bl %plt(__truncdfhf2)
+; LA64-NEXT:    st.h $a0, $fp, 0
+; LA64-NEXT:    ld.d $fp, $sp, 0 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $ra, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 16
+; LA64-NEXT:    ret
+  %a = fptrunc double %d to half
+  store half %a, ptr %p
+  ret void
+}
+
+define half @test_fadd_reg(half %a, half %b) nounwind {
+; LA32-LABEL: test_fadd_reg:
+; LA32:       # %bb.0:
+; LA32-NEXT:    addi.w $sp, $sp, -32
+; LA32-NEXT:    st.w $ra, $sp, 28 # 4-byte Folded Spill
+; LA32-NEXT:    fst.d $fs0, $sp, 16 # 8-byte Folded Spill
+; LA32-NEXT:    fst.d $fs1, $sp, 8 # 8-byte Folded Spill
+; LA32-NEXT:    fmov.s $fs0, $fa0
+; LA32-NEXT:    fmov.s $fa0, $fa1
+; LA32-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fmov.s $fs1, $fa0
+; LA32-NEXT:    fmov.s $fa0, $fs0
+; LA32-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fadd.s $fa0, $fa0, $fs1
+; LA32-NEXT:    fld.d $fs1, $sp, 8 # 8-byte Folded Reload
+; LA32-NEXT:    fld.d $fs0, $sp, 16 # 8-byte Folded Reload
+; LA32-NEXT:    ld.w $ra, $sp, 28 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 32
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_fadd_reg:
+; LA64:       # %bb.0:
+; LA64-NEXT:    addi.d $sp, $sp, -32
+; LA64-NEXT:    st.d $ra, $sp, 24 # 8-byte Folded Spill
+; LA64-NEXT:    fst.d $fs0, $sp, 16 # 8-byte Folded Spill
+; LA64-NEXT:    fst.d $fs1, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    fmov.s $fs0, $fa0
+; LA64-NEXT:    fmov.s $fa0, $fa1
+; LA64-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fmov.s $fs1, $fa0
+; LA64-NEXT:    fmov.s $fa0, $fs0
+; LA64-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fadd.s $fa0, $fa0, $fs1
+; LA64-NEXT:    fld.d $fs1, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    fld.d $fs0, $sp, 16 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $ra, $sp, 24 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 32
+; LA64-NEXT:    ret
+  %r = fadd half %a, %b
+  ret half %r
+}
+
+define void @test_fadd_mem(ptr %p, ptr %q) nounwind {
+; LA32-LABEL: test_fadd_mem:
+; LA32:       # %bb.0:
+; LA32-NEXT:    addi.w $sp, $sp, -32
+; LA32-NEXT:    st.w $ra, $sp, 28 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $fp, $sp, 24 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $s0, $sp, 20 # 4-byte Folded Spill
+; LA32-NEXT:    fst.d $fs0, $sp, 8 # 8-byte Folded Spill
+; LA32-NEXT:    move $fp, $a1
+; LA32-NEXT:    move $s0, $a0
+; LA32-NEXT:    ld.hu $a0, $a0, 0
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fmov.s $fs0, $fa0
+; LA32-NEXT:    ld.hu $a0, $fp, 0
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fadd.s $fa0, $fs0, $fa0
+; LA32-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA32-NEXT:    st.h $a0, $s0, 0
+; LA32-NEXT:    fld.d $fs0, $sp, 8 # 8-byte Folded Reload
+; LA32-NEXT:    ld.w $s0, $sp, 20 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $fp, $sp, 24 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $ra, $sp, 28 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 32
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_fadd_mem:
+; LA64:       # %bb.0:
+; LA64-NEXT:    addi.d $sp, $sp, -32
+; LA64-NEXT:    st.d $ra, $sp, 24 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $fp, $sp, 16 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $s0, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    fst.d $fs0, $sp, 0 # 8-byte Folded Spill
+; LA64-NEXT:    move $fp, $a1
+; LA64-NEXT:    move $s0, $a0
+; LA64-NEXT:    ld.hu $a0, $a0, 0
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fmov.s $fs0, $fa0
+; LA64-NEXT:    ld.hu $a0, $fp, 0
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fadd.s $fa0, $fs0, $fa0
+; LA64-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA64-NEXT:    st.h $a0, $s0, 0
+; LA64-NEXT:    fld.d $fs0, $sp, 0 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $s0, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $fp, $sp, 16 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $ra, $sp, 24 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 32
+; LA64-NEXT:    ret
+  %a = load half, ptr %p
+  %b = load half, ptr %q
+  %r = fadd half %a, %b
+  store half %r, ptr %p
+  ret void
+}
+
+define half @test_fmul_reg(half %a, half %b) nounwind {
+; LA32-LABEL: test_fmul_reg:
+; LA32:       # %bb.0:
+; LA32-NEXT:    addi.w $sp, $sp, -32
+; LA32-NEXT:    st.w $ra, $sp, 28 # 4-byte Folded Spill
+; LA32-NEXT:    fst.d $fs0, $sp, 16 # 8-byte Folded Spill
+; LA32-NEXT:    fst.d $fs1, $sp, 8 # 8-byte Folded Spill
+; LA32-NEXT:    fmov.s $fs0, $fa0
+; LA32-NEXT:    fmov.s $fa0, $fa1
+; LA32-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fmov.s $fs1, $fa0
+; LA32-NEXT:    fmov.s $fa0, $fs0
+; LA32-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fmul.s $fa0, $fa0, $fs1
+; LA32-NEXT:    fld.d $fs1, $sp, 8 # 8-byte Folded Reload
+; LA32-NEXT:    fld.d $fs0, $sp, 16 # 8-byte Folded Reload
+; LA32-NEXT:    ld.w $ra, $sp, 28 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 32
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_fmul_reg:
+; LA64:       # %bb.0:
+; LA64-NEXT:    addi.d $sp, $sp, -32
+; LA64-NEXT:    st.d $ra, $sp, 24 # 8-byte Folded Spill
+; LA64-NEXT:    fst.d $fs0, $sp, 16 # 8-byte Folded Spill
+; LA64-NEXT:    fst.d $fs1, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    fmov.s $fs0, $fa0
+; LA64-NEXT:    fmov.s $fa0, $fa1
+; LA64-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fmov.s $fs1, $fa0
+; LA64-NEXT:    fmov.s $fa0, $fs0
+; LA64-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fmul.s $fa0, $fa0, $fs1
+; LA64-NEXT:    fld.d $fs1, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    fld.d $fs0, $sp, 16 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $ra, $sp, 24 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 32
+; LA64-NEXT:    ret
+  %r = fmul half %a, %b
+  ret half %r
+}
+
+define void @test_fmul_mem(ptr %p, ptr %q) nounwind {
+; LA32-LABEL: test_fmul_mem:
+; LA32:       # %bb.0:
+; LA32-NEXT:    addi.w $sp, $sp, -32
+; LA32-NEXT:    st.w $ra, $sp, 28 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $fp, $sp, 24 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $s0, $sp, 20 # 4-byte Folded Spill
+; LA32-NEXT:    fst.d $fs0, $sp, 8 # 8-byte Folded Spill
+; LA32-NEXT:    move $fp, $a1
+; LA32-NEXT:    move $s0, $a0
+; LA32-NEXT:    ld.hu $a0, $a0, 0
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fmov.s $fs0, $fa0
+; LA32-NEXT:    ld.hu $a0, $fp, 0
+; LA32-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA32-NEXT:    fmul.s $fa0, $fs0, $fa0
+; LA32-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA32-NEXT:    st.h $a0, $s0, 0
+; LA32-NEXT:    fld.d $fs0, $sp, 8 # 8-byte Folded Reload
+; LA32-NEXT:    ld.w $s0, $sp, 20 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $fp, $sp, 24 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $ra, $sp, 28 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 32
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: test_fmul_mem:
+; LA64:       # %bb.0:
+; LA64-NEXT:    addi.d $sp, $sp, -32
+; LA64-NEXT:    st.d $ra, $sp, 24 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $fp, $sp, 16 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $s0, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    fst.d $fs0, $sp, 0 # 8-byte Folded Spill
+; LA64-NEXT:    move $fp, $a1
+; LA64-NEXT:    move $s0, $a0
+; LA64-NEXT:    ld.hu $a0, $a0, 0
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fmov.s $fs0, $fa0
+; LA64-NEXT:    ld.hu $a0, $fp, 0
+; LA64-NEXT:    bl %plt(__gnu_h2f_ieee)
+; LA64-NEXT:    fmul.s $fa0, $fs0, $fa0
+; LA64-NEXT:    bl %plt(__gnu_f2h_ieee)
+; LA64-NEXT:    st.h $a0, $s0, 0
+; LA64-NEXT:    fld.d $fs0, $sp, 0 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $s0, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $fp, $sp, 16 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $ra, $sp, 24 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 32
+; LA64-NEXT:    ret
+  %a = load half, ptr %p
+  %b = load half, ptr %q
+  %r = fmul half %a, %b
+  store half %r, ptr %p
+  ret void
+}