[X86] Enable half type support in inline assembly constraints

[LuoYuanke]

llvm/test/CodeGen/X86/inline-asm-avx512f-x-constraint.ll

22

Add more vector types (half, <8 x half>) to improve the coverage?

[pengfei]

Rebased.

llvm/test/CodeGen/X86/inline-asm-avx512f-x-constraint.ll

22

There will be many tests to meet the coverage, since we have the matrix {'v', 'x', 'Yz', ...} * 128/256/512. I checked we don't fully tested double either, I guess there might be no much value to do so since no difference among different FP types in SSE register classes.

[LuoYuanke]

llvm/test/CodeGen/X86/inline-asm-avx512f-x-constraint.ll

24

Maybe use a meaningful instruction, .e.g vaddph.

[pengfei]

Address Yuanke's comments.

[pengfei]

Thanks Yuanke.

[LuoYuanke]

LGTM, thanks!

llvm/lib/Target/X86/X86ISelLowering.cpp

     case 'v':
     case 'x':   // SSE_REGS if SSE1 allowed or AVX_REGS if AVX allowed
       if (!Subtarget.hasSSE1()) break;
       bool VConstraint = (Constraint[0] == 'v');
 
       switch (VT.SimpleTy) {
       default: break;
       // Scalar SSE types.
+      case MVT::f16:
+        if (VConstraint && Subtarget.hasFP16())
+          return std::make_pair(0U, &X86::FR16XRegClass);
+        break;
       case MVT::f32:
       case MVT::i32:
         if (VConstraint && Subtarget.hasVLX())
           return std::make_pair(0U, &X86::FR32XRegClass);
         return std::make_pair(0U, &X86::FR32RegClass);
       case MVT::f64:
       case MVT::i64:
         if (VConstraint && Subtarget.hasVLX())
           return std::make_pair(0U, &X86::FR64XRegClass);
         return std::make_pair(0U, &X86::FR64RegClass);
       case MVT::i128:
         if (Subtarget.is64Bit()) {
           if (VConstraint && Subtarget.hasVLX())
             return std::make_pair(0U, &X86::VR128XRegClass);
           return std::make_pair(0U, &X86::VR128RegClass);
         }
         break;
       // Vector types and fp128.
+      case MVT::v8f16:
+        if (!Subtarget.hasFP16())
+          break;
+        LLVM_FALLTHROUGH;
       case MVT::f128:
       case MVT::v16i8:
       case MVT::v8i16:
       case MVT::v4i32:
       case MVT::v2i64:
       case MVT::v4f32:
       case MVT::v2f64:
         if (VConstraint && Subtarget.hasVLX())
           return std::make_pair(0U, &X86::VR128XRegClass);
         return std::make_pair(0U, &X86::VR128RegClass);
       // AVX types.
+      case MVT::v16f16:
+        if (!Subtarget.hasFP16())
+          break;
+        LLVM_FALLTHROUGH;
       case MVT::v32i8:
       case MVT::v16i16:
       case MVT::v8i32:
       case MVT::v4i64:
       case MVT::v8f32:
       case MVT::v4f64:
         if (VConstraint && Subtarget.hasVLX())
           return std::make_pair(0U, &X86::VR256XRegClass);
         if (Subtarget.hasAVX())
           return std::make_pair(0U, &X86::VR256RegClass);
         break;
+      case MVT::v32f16:
+        if (!Subtarget.hasFP16())
+          break;
+        LLVM_FALLTHROUGH;
       case MVT::v64i8:
       case MVT::v32i16:
       case MVT::v8f64:
       case MVT::v16f32:
       case MVT::v16i32:
       case MVT::v8i64:
         if (!Subtarget.hasAVX512()) break;
         if (VConstraint)

     case 'm':
       if (!Subtarget.hasMMX()) break;
       return std::make_pair(0U, &X86::VR64RegClass);
     case 'z':
       if (!Subtarget.hasSSE1()) break;
       switch (VT.SimpleTy) {
       default: break;
       // Scalar SSE types.
+      case MVT::f16:
+        if (!Subtarget.hasFP16())
+          break;
+        return std::make_pair(X86::XMM0, &X86::FR16XRegClass);
       case MVT::f32:
       case MVT::i32:
         return std::make_pair(X86::XMM0, &X86::FR32RegClass);
       case MVT::f64:
       case MVT::i64:
         return std::make_pair(X86::XMM0, &X86::FR64RegClass);
+      case MVT::v8f16:
+        if (!Subtarget.hasFP16())
+          break;
+        LLVM_FALLTHROUGH;
       case MVT::f128:
       case MVT::v16i8:
       case MVT::v8i16:
       case MVT::v4i32:
       case MVT::v2i64:
       case MVT::v4f32:
       case MVT::v2f64:
         return std::make_pair(X86::XMM0, &X86::VR128RegClass);
       // AVX types.
+      case MVT::v16f16:
+        if (!Subtarget.hasFP16())
+          break;
+        LLVM_FALLTHROUGH;
       case MVT::v32i8:
       case MVT::v16i16:
       case MVT::v8i32:
       case MVT::v4i64:
       case MVT::v8f32:
       case MVT::v4f64:
         if (Subtarget.hasAVX())
           return std::make_pair(X86::YMM0, &X86::VR256RegClass);
         break;
+      case MVT::v32f16:
+        if (!Subtarget.hasFP16())
+          break;
+        LLVM_FALLTHROUGH;
       case MVT::v64i8:
       case MVT::v32i16:
       case MVT::v8f64:
       case MVT::v16f32:
       case MVT::v16i32:
       case MVT::v8i64:
         if (Subtarget.hasAVX512())
           return std::make_pair(X86::ZMM0, &X86::VR512_0_15RegClass);

     return std::make_pair(0, nullptr);
   } else if (isFRClass(*Class)) {
     // Handle references to XMM physical registers that got mapped into the
     // wrong class.  This can happen with constraints like {xmm0} where the
     // target independent register mapper will just pick the first match it can
     // find, ignoring the required type.
 
     // TODO: Handle f128 and i128 in FR128RegClass after it is tested well.
-    if (VT == MVT::f32 || VT == MVT::i32)
+    if (VT == MVT::f16)
+      Res.second = &X86::FR16XRegClass;
+    else if (VT == MVT::f32 || VT == MVT::i32)
       Res.second = &X86::FR32XRegClass;
     else if (VT == MVT::f64 || VT == MVT::i64)
       Res.second = &X86::FR64XRegClass;
     else if (TRI->isTypeLegalForClass(X86::VR128XRegClass, VT))
       Res.second = &X86::VR128XRegClass;
     else if (TRI->isTypeLegalForClass(X86::VR256XRegClass, VT))
       Res.second = &X86::VR256XRegClass;
     else if (TRI->isTypeLegalForClass(X86::VR512RegClass, VT))

llvm/test/CodeGen/X86/inline-asm-avx512f-x-constraint.ll

-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx512f -stop-after=finalize-isel | FileCheck %s
+; RUN: not llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx512f -stop-after=finalize-isel > %t 2> %t.err
+; RUN: FileCheck < %t %s
+; RUN: FileCheck --check-prefix=CHECK-STDERR < %t.err %s
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx512fp16 -stop-after=finalize-isel | FileCheck --check-prefixes=CHECK,FP16 %s
 
+; CHECK-LABEL: name: mask_Yk_i8
 ; CHECK: %[[REG1:.*]]:vr512_0_15 = COPY %1
 ; CHECK: %[[REG2:.*]]:vr512_0_15 = COPY %2
 ; CHECK: INLINEASM &"vpaddq\09$3, $2, $0 {$1}", 0 /* attdialect */, {{.*}}, def %{{.*}}, {{.*}}, %{{.*}}, {{.*}}, %[[REG1]], {{.*}}, %[[REG2]], 12 /* clobber */, implicit-def early-clobber $df, 12 /* clobber */, implicit-def early-clobber $fpsw, 12 /* clobber */, implicit-def early-clobber $eflags
 
 define <8 x i64> @mask_Yk_i8(i8 signext %msk, <8 x i64> %x, <8 x i64> %y) {
 entry:
   %0 = tail call <8 x i64> asm "vpaddq\09$3, $2, $0 {$1}", "=x,^Yk,x,x,~{dirflag},~{fpsr},~{flags}"(i8 %msk, <8 x i64> %x, <8 x i64> %y)
   ret <8 x i64> %0
 }
+
+; FP16-LABEL: name: mask_Yk_f16
+; FP16: %[[REG1:.*]]:vr512_0_15 = COPY %1
+; FP16: %[[REG2:.*]]:vr512_0_15 = COPY %2
+; FP16: INLINEASM &"vaddph\09$3, $2, $0 {$1}", 0 /* attdialect */, {{.*}}, def %{{.*}}, {{.*}}, %{{.*}}, {{.*}}, %[[REG1]], {{.*}}, %[[REG2]], 12 /* clobber */, implicit-def early-clobber $df, 12 /* clobber */, implicit-def early-clobber $fpsw, 12 /* clobber */, implicit-def early-clobber $eflags
+; CHECK-STDERR: couldn't allocate output register for constraint 'x'
+define <32 x half> @mask_Yk_f16(i8 signext %msk, <32 x half> %x, <32 x half> %y) {
+entry:
+  %0 = tail call <32 x half> asm "vaddph\09$3, $2, $0 {$1}", "=x,^Yk,x,x,~{dirflag},~{fpsr},~{flags}"(i8 %msk, <32 x half> %x, <32 x half> %y)
+  ret <32 x half> %0
+}