[MIPS GlobalISel] Select G_SELECT

Add widen scalar for type index 1 (i1 condition) for G_SELECT.
Select G_SELECT for pointer, s32(integer) and smaller low level
types on MIPS32.

Differential Revision: https://reviews.llvm.org/D56001

llvm-svn: 350063

4 files changed, 32 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 274bc4bf695..facbafaf509 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -777,15 +777,18 @@ LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
     return Legalized;
 
   case TargetOpcode::G_SELECT:
-    if (TypeIdx != 0)
-      return UnableToLegalize;
-    // Perform operation at larger width (any extension is fine here, high bits
-    // don't affect the result) and then truncate the result back to the
-    // original type.
     Observer.changingInstr(MI);
-    widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_ANYEXT);
-    widenScalarSrc(MI, WideTy, 3, TargetOpcode::G_ANYEXT);
-    widenScalarDst(MI, WideTy);
+    if (TypeIdx == 0) {
+      // Perform operation at larger width (any extension is fine here, high
+      // bits don't affect the result) and then truncate the result back to the
+      // original type.
+      widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_ANYEXT);
+      widenScalarSrc(MI, WideTy, 3, TargetOpcode::G_ANYEXT);
+      widenScalarDst(MI, WideTy);
+    } else {
+      // Explicit extension is required here since high bits affect the result.
+      widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ZEXT);
+    }
     Observer.changedInstr(MI);
     return Legalized;
 
diff --git a/llvm/lib/Target/Mips/MipsInstructionSelector.cpp b/llvm/lib/Target/Mips/MipsInstructionSelector.cpp
index 4964ca9cbe1..b041590ee34 100644
--- a/llvm/lib/Target/Mips/MipsInstructionSelector.cpp
+++ b/llvm/lib/Target/Mips/MipsInstructionSelector.cpp
@@ -172,6 +172,15 @@ bool MipsInstructionSelector::select(MachineInstr &I,
     I.eraseFromParent();
     return true;
   }
+  case G_SELECT: {
+    // Handle operands with pointer type.
+    MI = BuildMI(MBB, I, I.getDebugLoc(), TII.get(Mips::MOVN_I_I))
+             .add(I.getOperand(0))
+             .add(I.getOperand(2))
+             .add(I.getOperand(1))
+             .add(I.getOperand(3));
+    break;
+  }
   case G_CONSTANT: {
     int Imm = I.getOperand(1).getCImm()->getValue().getLimitedValue();
     unsigned LUiReg = MRI.createVirtualRegister(&Mips::GPR32RegClass);
diff --git a/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp b/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
index 0d80bd479d5..c629f02af00 100644
--- a/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsLegalizerInfo.cpp
@@ -35,6 +35,11 @@ MipsLegalizerInfo::MipsLegalizerInfo(const MipsSubtarget &ST) {
   getActionDefinitionsBuilder({G_LOAD, G_STORE})
       .legalForCartesianProduct({p0, s32}, {p0});
 
+  getActionDefinitionsBuilder(G_SELECT)
+      .legalForCartesianProduct({p0, s32}, {s32})
+      .minScalar(0, s32)
+      .minScalar(1, s32);
+
   getActionDefinitionsBuilder({G_AND, G_OR, G_XOR})
       .legalFor({s32})
       .clampScalar(0, s32, s32);
diff --git a/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp b/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp
index 53b9e42dc63..6af1f10189d 100644
--- a/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsRegisterBankInfo.cpp
@@ -111,6 +111,13 @@ MipsRegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
                             &Mips::ValueMappings[Mips::GPRIdx],
                             &Mips::ValueMappings[Mips::GPRIdx]});
     break;
+  case G_SELECT:
+    OperandsMapping =
+        getOperandsMapping({&Mips::ValueMappings[Mips::GPRIdx],
+                            &Mips::ValueMappings[Mips::GPRIdx],
+                            &Mips::ValueMappings[Mips::GPRIdx],
+                            &Mips::ValueMappings[Mips::GPRIdx]});
+    break;
   default:
     return getInvalidInstructionMapping();
   }