[X86] Demote EmitTest to a helper function of EmitCmp. Route all callers except EmitCmp through EmitCmp.

This requires the two callers to manifest a 0 to make EmitCmp call EmitTest.

I'm looking into changing how we combine TEST and flag setting instructions to not be part of lowering. And instead be part of DAG combine or isel. Which will mean EmitTest will probably become gutted and maybe disappear entirely.

llvm-svn: 349094

2 files changed, 9 insertions, 14 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index b9f3729ac80..f669ff123bd 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -18537,8 +18537,8 @@ static bool hasNonFlagsUse(SDValue Op) {
 
 /// Emit nodes that will be selected as "test Op0,Op0", or something
 /// equivalent.
-SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC, const SDLoc &dl,
-                                    SelectionDAG &DAG) const {
+static SDValue EmitTest(SDValue Op, unsigned X86CC, const SDLoc &dl,
+                        SelectionDAG &DAG, const X86Subtarget &Subtarget) {
   // CF and OF aren't always set the way we want. Determine which
   // of these we need.
   bool NeedCF = false;
@@ -18713,8 +18713,7 @@ SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC, const SDLoc &dl,
         if (LeadingOnes + TrailingZeros == BitWidth) {
           assert(TrailingZeros < VT.getSizeInBits() &&
                  "Shift amount should be less than the type width");
-          MVT ShTy = getScalarShiftAmountTy(DAG.getDataLayout(), VT);
-          SDValue ShAmt = DAG.getConstant(TrailingZeros, dl, ShTy);
+          SDValue ShAmt = DAG.getConstant(TrailingZeros, dl, MVT::i8);
           Op = DAG.getNode(ISD::SRL, dl, VT, Op0, ShAmt);
           break;
         }
@@ -18725,8 +18724,7 @@ SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC, const SDLoc &dl,
         if (LeadingZeros + TrailingOnes == BitWidth) {
           assert(LeadingZeros < VT.getSizeInBits() &&
                  "Shift amount should be less than the type width");
-          MVT ShTy = getScalarShiftAmountTy(DAG.getDataLayout(), VT);
-          SDValue ShAmt = DAG.getConstant(LeadingZeros, dl, ShTy);
+          SDValue ShAmt = DAG.getConstant(LeadingZeros, dl, MVT::i8);
           Op = DAG.getNode(ISD::SHL, dl, VT, Op0, ShAmt);
           break;
         }
@@ -18819,7 +18817,7 @@ SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC, const SDLoc &dl,
 SDValue X86TargetLowering::EmitCmp(SDValue Op0, SDValue Op1, unsigned X86CC,
                                    const SDLoc &dl, SelectionDAG &DAG) const {
   if (isNullConstant(Op1))
-    return EmitTest(Op0, X86CC, dl, DAG);
+    return EmitTest(Op0, X86CC, dl, DAG, Subtarget);
 
   if ((Op0.getValueType() == MVT::i8 || Op0.getValueType() == MVT::i16 ||
        Op0.getValueType() == MVT::i32 || Op0.getValueType() == MVT::i64)) {
@@ -19948,7 +19946,8 @@ SDValue X86TargetLowering::LowerSELECT(SDValue Op, SelectionDAG &DAG) const {
 
   if (AddTest) {
     CC = DAG.getConstant(X86::COND_NE, DL, MVT::i8);
-    Cond = EmitTest(Cond, X86::COND_NE, DL, DAG);
+    Cond = EmitCmp(Cond, DAG.getConstant(0, DL, Cond.getValueType()),
+                   X86::COND_NE, DL, DAG);
   }
 
   // a <  b ? -1 :  0 -> RES = ~setcc_carry
@@ -20795,7 +20794,8 @@ SDValue X86TargetLowering::LowerBRCOND(SDValue Op, SelectionDAG &DAG) const {
   if (addTest) {
     X86::CondCode X86Cond = Inverted ? X86::COND_E : X86::COND_NE;
     CC = DAG.getConstant(X86Cond, dl, MVT::i8);
-    Cond = EmitTest(Cond, X86Cond, dl, DAG);
+    Cond = EmitCmp(Cond, DAG.getConstant(0, dl, Cond.getValueType()),
+                   X86Cond, dl, DAG);
   }
   Cond = ConvertCmpIfNecessary(Cond, DAG);
   return DAG.getNode(X86ISD::BRCOND, dl, Op.getValueType(),
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index e2a8eaacb3b..3a7078a3db2 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1362,11 +1362,6 @@ namespace llvm {
     MachineBasicBlock *EmitSjLjDispatchBlock(MachineInstr &MI,
                                              MachineBasicBlock *MBB) const;
 
-    /// Emit nodes that will be selected as "test Op0,Op0", or something
-    /// equivalent, for use with the given x86 condition code.
-    SDValue EmitTest(SDValue Op0, unsigned X86CC, const SDLoc &dl,
-                     SelectionDAG &DAG) const;
-
     /// Emit nodes that will be selected as "cmp Op0,Op1", or something
     /// equivalent, for use with the given x86 condition code.
     SDValue EmitCmp(SDValue Op0, SDValue Op1, unsigned X86CC, const SDLoc &dl,