[AArch64][SVE] Add lowering for llvm.maxnum|minnum for scalable type.

[huihuiz]

Summary

LLVM intrinsic llvm.maxnum|minnum is overloaded intrinsic, can be used on any
floating-point or vector of floating-point type.
This patch extends current infrastructure to support scalable vector type.

This patch also fix a warning message of incorrect use of EVT::getVectorNumElements()
for scalable type, when DAGCombiner trying to split scalable vector.

[sdesmalen]

llvm/test/CodeGen/AArch64/sve-fp.ll

597

Can you also add at least one case for each intrinsic (maxnum and minnum) where the vector needs splitting? e.g. using either nxv16f16, nxv8f32 or nxv4f64.

[huihuiz]

Thanks for the feedback!
Test cases for vector splitting added. Also fix the warning message caused by extracting subvector.

[sdesmalen]

Thanks for adding the tests and fixing the warnings, LGTM!

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

       setOperationAction(ISD::CONCAT_VECTORS, VT, Custom);
       setOperationAction(ISD::INSERT_SUBVECTOR, VT, Custom);
       setOperationAction(ISD::MSCATTER, VT, Custom);
       setOperationAction(ISD::SPLAT_VECTOR, VT, Custom);
       setOperationAction(ISD::SELECT, VT, Custom);
       setOperationAction(ISD::FADD, VT, Custom);
       setOperationAction(ISD::FDIV, VT, Custom);
       setOperationAction(ISD::FMA, VT, Custom);
+      setOperationAction(ISD::FMAXNUM, VT, Custom);
+      setOperationAction(ISD::FMINNUM, VT, Custom);
       setOperationAction(ISD::FMUL, VT, Custom);
       setOperationAction(ISD::FNEG, VT, Custom);
       setOperationAction(ISD::FSUB, VT, Custom);
       setOperationAction(ISD::FCEIL, VT, Custom);
       setOperationAction(ISD::FFLOOR, VT, Custom);
       setOperationAction(ISD::FNEARBYINT, VT, Custom);
       setOperationAction(ISD::FRINT, VT, Custom);
       setOperationAction(ISD::FROUND, VT, Custom);

llvm/test/CodeGen/AArch64/sve-fp.ll

 ; CHECK:       // %bb.0:
 ; CHECK-NEXT:    ptrue p0.d
 ; CHECK-NEXT:    fabs z0.d, p0/m, z0.d
 ; CHECK-NEXT:    ret
   %res = call <vscale x 2 x double> @llvm.fabs.nxv2f64(<vscale x 2 x double> %a)
   ret <vscale x 2 x double> %res
 }
 
+; maxnum minmum
+
+define <vscale x 8 x half> @maxnum_nxv8f16(<vscale x 8 x half> %a, <vscale x 8 x half> %b) {
+; CHECK-LABEL: maxnum_nxv8f16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.h
+; CHECK-NEXT:    fmaxnm z0.h, p0/m, z0.h, z1.h
+; CHECK-NEXT:    ret
+  %res = call <vscale x 8 x half> @llvm.maxnum.nxv8f16(<vscale x 8 x half> %a, <vscale x 8 x half> %b)
+  ret <vscale x 8 x half> %res
+}
+
+define <vscale x 4 x half> @maxnum_nxv4f16(<vscale x 4 x half> %a, <vscale x 4 x half> %b) {
+; CHECK-LABEL: maxnum_nxv4f16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.s
+; CHECK-NEXT:    fmaxnm z0.h, p0/m, z0.h, z1.h
+; CHECK-NEXT:    ret
+  %res = call <vscale x 4 x half> @llvm.maxnum.nxv4f16(<vscale x 4 x half> %a, <vscale x 4 x half> %b)
+  ret <vscale x 4 x half> %res
+}
+
+define <vscale x 2 x half> @maxnum_nxv2f16(<vscale x 2 x half> %a, <vscale x 2 x half> %b) {
+; CHECK-LABEL: maxnum_nxv2f16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.d
+; CHECK-NEXT:    fmaxnm z0.h, p0/m, z0.h, z1.h
+; CHECK-NEXT:    ret
+  %res = call <vscale x 2 x half> @llvm.maxnum.nxv2f16(<vscale x 2 x half> %a, <vscale x 2 x half> %b)
+  ret <vscale x 2 x half> %res
+}
+
+define <vscale x 4 x float> @maxnum_nxv4f32(<vscale x 4 x float> %a, <vscale x 4 x float> %b) {
+; CHECK-LABEL: maxnum_nxv4f32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.s
+; CHECK-NEXT:    fmaxnm z0.s, p0/m, z0.s, z1.s
+; CHECK-NEXT:    ret
+  %res = call <vscale x 4 x float> @llvm.maxnum.nxv4f32(<vscale x 4 x float> %a, <vscale x 4 x float> %b)
+  ret <vscale x 4 x float> %res
+}
+
+define <vscale x 2 x float> @maxnum_nxv2f32(<vscale x 2 x float> %a, <vscale x 2 x float> %b) {
+; CHECK-LABEL: maxnum_nxv2f32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.d
+; CHECK-NEXT:    fmaxnm z0.s, p0/m, z0.s, z1.s
+; CHECK-NEXT:    ret
+  %res = call <vscale x 2 x float> @llvm.maxnum.nxv2f32(<vscale x 2 x float> %a, <vscale x 2 x float> %b)
+  ret <vscale x 2 x float> %res
+}
+
+define <vscale x 2 x double> @maxnum_nxv2f64(<vscale x 2 x double> %a, <vscale x 2 x double> %b) {
+; CHECK-LABEL: maxnum_nxv2f64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.d
+; CHECK-NEXT:    fmaxnm z0.d, p0/m, z0.d, z1.d
+; CHECK-NEXT:    ret
+  %res = call <vscale x 2 x double> @llvm.maxnum.nxv2f64(<vscale x 2 x double> %a, <vscale x 2 x double> %b)
+  ret <vscale x 2 x double> %res
+}
+
+define <vscale x 8 x half> @minnum_nxv8f16(<vscale x 8 x half> %a, <vscale x 8 x half> %b) {
+; CHECK-LABEL: minnum_nxv8f16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.h
+; CHECK-NEXT:    fminnm z0.h, p0/m, z0.h, z1.h
+; CHECK-NEXT:    ret
+  %res = call <vscale x 8 x half> @llvm.minnum.nxv8f16(<vscale x 8 x half> %a, <vscale x 8 x half> %b)
+  ret <vscale x 8 x half> %res
+}
+
+define <vscale x 4 x half> @minnum_nxv4f16(<vscale x 4 x half> %a, <vscale x 4 x half> %b) {
+; CHECK-LABEL: minnum_nxv4f16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.s
+; CHECK-NEXT:    fminnm z0.h, p0/m, z0.h, z1.h
+; CHECK-NEXT:    ret
+  %res = call <vscale x 4 x half> @llvm.minnum.nxv4f16(<vscale x 4 x half> %a, <vscale x 4 x half> %b)
+  ret <vscale x 4 x half> %res
+}
+
+define <vscale x 2 x half> @minnum_nxv2f16(<vscale x 2 x half> %a, <vscale x 2 x half> %b) {
+; CHECK-LABEL: minnum_nxv2f16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.d
+; CHECK-NEXT:    fminnm z0.h, p0/m, z0.h, z1.h
+; CHECK-NEXT:    ret
+  %res = call <vscale x 2 x half> @llvm.minnum.nxv2f16(<vscale x 2 x half> %a, <vscale x 2 x half> %b)
+  ret <vscale x 2 x half> %res
+}
+
+define <vscale x 4 x float> @minnum_nxv4f32(<vscale x 4 x float> %a, <vscale x 4 x float> %b) {
+; CHECK-LABEL: minnum_nxv4f32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.s
+; CHECK-NEXT:    fminnm z0.s, p0/m, z0.s, z1.s
+; CHECK-NEXT:    ret
+  %res = call <vscale x 4 x float> @llvm.minnum.nxv4f32(<vscale x 4 x float> %a, <vscale x 4 x float> %b)
+  ret <vscale x 4 x float> %res
+}
+
+define <vscale x 2 x float> @minnum_nxv2f32(<vscale x 2 x float> %a, <vscale x 2 x float> %b) {
+; CHECK-LABEL: minnum_nxv2f32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.d
+; CHECK-NEXT:    fminnm z0.s, p0/m, z0.s, z1.s
+; CHECK-NEXT:    ret
+  %res = call <vscale x 2 x float> @llvm.minnum.nxv2f32(<vscale x 2 x float> %a, <vscale x 2 x float> %b)
+  ret <vscale x 2 x float> %res
+}
+
+define <vscale x 2 x double> @minnum_nxv2f64(<vscale x 2 x double> %a, <vscale x 2 x double> %b) {
+; CHECK-LABEL: minnum_nxv2f64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ptrue p0.d
+; CHECK-NEXT:    fminnm z0.d, p0/m, z0.d, z1.d
+; CHECK-NEXT:    ret
+  %res = call <vscale x 2 x double> @llvm.minnum.nxv2f64(<vscale x 2 x double> %a, <vscale x 2 x double> %b)
+  ret <vscale x 2 x double> %res
+}
+
 declare <vscale x 8 x half> @llvm.aarch64.sve.frecps.x.nxv8f16(<vscale x 8 x half>, <vscale x 8 x half>)
 declare <vscale x 4 x float>  @llvm.aarch64.sve.frecps.x.nxv4f32(<vscale x 4 x float> , <vscale x 4 x float>)
 declare <vscale x 2 x double> @llvm.aarch64.sve.frecps.x.nxv2f64(<vscale x 2 x double>, <vscale x 2 x double>)
 
 declare <vscale x 8 x half> @llvm.aarch64.sve.frsqrts.x.nxv8f16(<vscale x 8 x half>, <vscale x 8 x half>)
 declare <vscale x 4 x float> @llvm.aarch64.sve.frsqrts.x.nxv4f32(<vscale x 4 x float>, <vscale x 4 x float>)
 declare <vscale x 2 x double> @llvm.aarch64.sve.frsqrts.x.nxv2f64(<vscale x 2 x double>, <vscale x 2 x double>)
 

 
 declare <vscale x 8 x half> @llvm.fabs.nxv8f16( <vscale x 8 x half>)
 declare <vscale x 4 x half> @llvm.fabs.nxv4f16( <vscale x 4 x half>)
 declare <vscale x 2 x half> @llvm.fabs.nxv2f16( <vscale x 2 x half>)
 declare <vscale x 4 x float> @llvm.fabs.nxv4f32(<vscale x 4 x float>)
 declare <vscale x 2 x float> @llvm.fabs.nxv2f32(<vscale x 2 x float>)
 declare <vscale x 2 x double> @llvm.fabs.nxv2f64(<vscale x 2 x double>)
 
+declare <vscale x 8 x half> @llvm.maxnum.nxv8f16(<vscale x 8 x half>, <vscale x 8 x half>)
+declare <vscale x 4 x half> @llvm.maxnum.nxv4f16(<vscale x 4 x half>, <vscale x 4 x half>)
+declare <vscale x 2 x half> @llvm.maxnum.nxv2f16(<vscale x 2 x half>, <vscale x 2 x half>)
+declare <vscale x 4 x float> @llvm.maxnum.nxv4f32(<vscale x 4 x float>, <vscale x 4 x float>)
+declare <vscale x 2 x float> @llvm.maxnum.nxv2f32(<vscale x 2 x float>, <vscale x 2 x float>)
+declare <vscale x 2 x double> @llvm.maxnum.nxv2f64(<vscale x 2 x double>, <vscale x 2 x double>)
+declare <vscale x 8 x half> @llvm.minnum.nxv8f16(<vscale x 8 x half>, <vscale x 8 x half>)
+declare <vscale x 4 x half> @llvm.minnum.nxv4f16(<vscale x 4 x half>, <vscale x 4 x half>)
+declare <vscale x 2 x half> @llvm.minnum.nxv2f16(<vscale x 2 x half>, <vscale x 2 x half>)
+declare <vscale x 4 x float> @llvm.minnum.nxv4f32(<vscale x 4 x float>, <vscale x 4 x float>)
+declare <vscale x 2 x float> @llvm.minnum.nxv2f32(<vscale x 2 x float>, <vscale x 2 x float>)
+declare <vscale x 2 x double> @llvm.minnum.nxv2f64(<vscale x 2 x double>, <vscale x 2 x double>)
+
 ; Function Attrs: nounwind readnone
 declare double @llvm.aarch64.sve.faddv.nxv2f64(<vscale x 2 x i1>, <vscale x 2 x double>) #2