[GlobalISel] Add G_IS_FPCLASS

Add a generic opcode to represent `llvm.is_fpclass` intrinsic.

Differential Revision: https://reviews.llvm.org/D121454

Author: spavloff

llvm/docs/GlobalISel/GenericOpcode.rst

@@ -480,6 +480,16 @@ G_FCANONICALIZE
 
 See :ref:`i_intr_llvm_canonicalize`.
 
+G_IS_FPCLASS
+^^^^^^^^^^^^
+
+Tests if the first operand, which must be floating-point scalar or vector, has
+floating-point class specified by the second operand. The third operand
+specifies floating-point semantics of the tested value. Returns non-zero (true)
+or zero (false). It's target specific whether a true value is 1, ~0U, or some
+other non-zero value. If the first operand is a vector, the returned value is a
+vector of the same length.
+
 G_FMINNUM
 ^^^^^^^^^
 

llvm/include/llvm/ADT/APFloat.h

@@ -155,7 +155,8 @@ struct APFloatBase {
     S_IEEEdouble,
     S_x87DoubleExtended,
     S_IEEEquad,
-    S_PPCDoubleDouble
+    S_PPCDoubleDouble,
+    S_MaxSemantics = S_PPCDoubleDouble
   };
 
   static const llvm::fltSemantics &EnumToSemantics(Semantics S);

llvm/include/llvm/Support/TargetOpcodes.def

@@ -620,6 +620,9 @@ HANDLE_TARGET_OPCODE(G_FABS)
 /// f64) is allowed.
 HANDLE_TARGET_OPCODE(G_FCOPYSIGN)
 
+/// Generic test for floating-point class.
+HANDLE_TARGET_OPCODE(G_IS_FPCLASS)
+
 /// Generic FP canonicalize value.
 HANDLE_TARGET_OPCODE(G_FCANONICALIZE)
 

llvm/include/llvm/Target/GenericOpcodes.td

@@ -745,6 +745,13 @@ def G_FCANONICALIZE : GenericInstruction {
   let hasSideEffects = false;
 }
 
+// Generic opcode equivalent to the llvm.is_fpclass intrinsic.
+def G_IS_FPCLASS: GenericInstruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins type1:$src, unknown:$test, unknown:$fpsem);
+  let hasSideEffects = false;
+}
+
 // FMINNUM/FMAXNUM - Perform floating-point minimum or maximum on two
 // values.
 //

llvm/lib/CodeGen/MachineVerifier.cpp

@@ -32,6 +32,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Analysis/EHPersonalities.h"
+#include "llvm/CodeGen/CodeGenCommonISel.h"
 #include "llvm/CodeGen/LiveInterval.h"
 #include "llvm/CodeGen/LiveIntervals.h"
 #include "llvm/CodeGen/LiveRangeCalc.h"
@@ -1650,6 +1651,43 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
     verifyAllRegOpsScalar(*MI, *MRI);
     break;
   }
+  case TargetOpcode::G_IS_FPCLASS: {
+    LLT DestTy = MRI->getType(MI->getOperand(0).getReg());
+    LLT DestEltTy = DestTy.getScalarType();
+    if (!DestEltTy.isScalar()) {
+      report("Destination must be a scalar or vector of scalars", MI);
+      break;
+    }
+    LLT SrcTy = MRI->getType(MI->getOperand(1).getReg());
+    LLT SrcEltTy = SrcTy.getScalarType();
+    if (!SrcEltTy.isScalar()) {
+      report("Source must be a scalar or vector of scalars", MI);
+      break;
+    }
+    if (!verifyVectorElementMatch(DestTy, SrcTy, MI))
+      break;
+    const MachineOperand &TestMO = MI->getOperand(2);
+    if (!TestMO.isImm()) {
+      report("floating-point class set (operand 2) must be an immediate", MI);
+      break;
+    }
+    int64_t Test = TestMO.getImm();
+    if (Test < 0 || Test > fcAllFlags) {
+      report("Incorrect floating-point class set (operand 2)", MI);
+      break;
+    }
+    const MachineOperand &SemanticsMO = MI->getOperand(3);
+    if (!SemanticsMO.isImm()) {
+      report("floating-point semantics (operand 3) must be an immediate", MI);
+      break;
+    }
+    int64_t Semantics = SemanticsMO.getImm();
+    if (Semantics < 0 || Semantics > APFloat::S_MaxSemantics) {
+      report("Incorrect floating-point semantics (operand 3)", MI);
+      break;
+    }
+    break;
+  }
   default:
     break;
   }

llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir

@@ -484,6 +484,9 @@
 # DEBUG-NEXT: G_FCOPYSIGN (opcode {{[0-9]+}}): 2 type indices
 # DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: G_IS_FPCLASS (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
+# DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
+# DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: G_FCANONICALIZE (opcode {{[0-9]+}}): 1 type index, 0 imm indices
 # DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined

llvm/test/MachineVerifier/test_g_is_fpclass.mir

@@ -0,0 +1,40 @@
+# RUN: not --crash llc -o - -march=aarch64 -global-isel -run-pass=none -verify-machineinstrs %s 2>&1 | FileCheck %s
+# REQUIRES: aarch64-registered-target
+
+---
+name:            test_fcmp
+legalized:       true
+regBankSelected: false
+selected:        false
+tracksRegLiveness: true
+liveins:
+body:             |
+  bb.0:
+    liveins: $x0, $w0, $q0
+    %s32:_(s32) = COPY $w0
+    %ptr:_(p0) = COPY $x0
+    %vector:_(<4 x s32>) = COPY $q0
+
+    %val1:_(s1) = G_IS_FPCLASS %s32, 1
+    ; CHECK: *** Bad machine code: Too few operands ***
+    ; CHECK: 4 operands expected, but 3 given.
+
+    %val2:_(p0) = G_IS_FPCLASS %s32, 3, 2
+    ; CHECK: *** Bad machine code: Destination must be a scalar or vector of scalars ***
+
+    %val3:_(s1) = G_IS_FPCLASS %s32, 1, 66
+    ; CHECK: *** Bad machine code: Incorrect floating-point semantics (operand 3) ***
+
+    %val4:_(s1) = G_IS_FPCLASS %s32, 7777, 2
+    ; CHECK: *** Bad machine code: Incorrect floating-point class set (operand 2) ***
+
+    %val5:_(s1) = G_IS_FPCLASS %ptr:_(p0), 3, 2
+    ; CHECK: *** Bad machine code: Source must be a scalar or vector of scalars ***
+
+    %var6:_(s1) = G_IS_FPCLASS %vector:_(<4 x s32>), 1, 2
+    ; CHECK: *** Bad machine code: operand types must be all-vector or all-scalar ***
+
+    %var7:_(<2 x s1>) = G_IS_FPCLASS %vector:_(<4 x s32>), 1, 2
+    ; CHECK: *** Bad machine code: operand types must preserve number of vector elements ***
+
+...