[WebAssembly] Use the same lowerings for f16x8 as other float vectors. (#127897)

This fixes failures to select the various compare operations that
weren't being expanded for f16x8.

Author: brendandahl

llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp

@@ -121,7 +121,10 @@ WebAssemblyTargetLowering::WebAssemblyTargetLowering(
   setOperationAction(ISD::VACOPY, MVT::Other, Expand);
   setOperationAction(ISD::VAEND, MVT::Other, Expand);
 
-  for (auto T : {MVT::f32, MVT::f64, MVT::v4f32, MVT::v2f64}) {
+  for (auto T : {MVT::f32, MVT::f64, MVT::v4f32, MVT::v2f64, MVT::v8f16}) {
+    if (!Subtarget->hasFP16() && T == MVT::v8f16) {
+      continue;
+    }
     // Don't expand the floating-point types to constant pools.
     setOperationAction(ISD::ConstantFP, T, Legal);
     // Expand floating-point comparisons.
@@ -140,18 +143,16 @@ WebAssemblyTargetLowering::WebAssemblyTargetLowering(
     // Support minimum and maximum, which otherwise default to expand.
     setOperationAction(ISD::FMINIMUM, T, Legal);
     setOperationAction(ISD::FMAXIMUM, T, Legal);
-    // WebAssembly currently has no builtin f16 support.
-    setOperationAction(ISD::FP16_TO_FP, T, Expand);
-    setOperationAction(ISD::FP_TO_FP16, T, Expand);
+    // When experimental v8f16 support is enabled these instructions don't need
+    // to be expanded.
+    if (T != MVT::v8f16) {
+      setOperationAction(ISD::FP16_TO_FP, T, Expand);
+      setOperationAction(ISD::FP_TO_FP16, T, Expand);
+    }
     setLoadExtAction(ISD::EXTLOAD, T, MVT::f16, Expand);
     setTruncStoreAction(T, MVT::f16, Expand);
   }
 
-  if (Subtarget->hasFP16()) {
-    setOperationAction(ISD::FMINIMUM, MVT::v8f16, Legal);
-    setOperationAction(ISD::FMAXIMUM, MVT::v8f16, Legal);
-  }
-
   // Expand unavailable integer operations.
   for (auto Op :
        {ISD::BSWAP, ISD::SMUL_LOHI, ISD::UMUL_LOHI, ISD::MULHS, ISD::MULHU,

llvm/test/CodeGen/WebAssembly/half-precision.ll

@@ -172,6 +172,16 @@ define <8 x i1> @compare_oge_v8f16 (<8 x half> %x, <8 x half> %y) {
   ret <8 x i1> %res
 }
 
+; CHECK-LABEL: compare_ule_v8f16:
+; CHECK-NEXT: .functype compare_ule_v8f16 (v128, v128) -> (v128){{$}}
+; CHECK-NEXT: f16x8.gt $push[[T0:[0-9]+]]=, $0, $1{{$}}
+; CHECK-NEXT: v128.not $push[[R:[0-9]+]]=, $pop[[T0]]{{$}}
+; CHECK-NEXT: return $pop[[R]]{{$}}
+define <8 x i1> @compare_ule_v8f16 (<8 x half> %x, <8 x half> %y) {
+  %res = fcmp ule <8 x half> %x, %y
+  ret <8 x i1> %res
+}
+
 ; CHECK-LABEL: abs_v8f16:
 ; CHECK-NEXT:  .functype abs_v8f16 (v128) -> (v128)
 ; CHECK-NEXT:  f16x8.abs $push0=, $0