[PATCH] D37673: [X86] Remove portions of r275950 that are no longer needed with i1 not being a legal type

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.

r275950 added support for turning (trunc (X >> N) to i1) into BT(X, N). But that's no longer necessary now that i1 isn't legal.

This patch removes the support for that, but preserves some of the refactorings done in that commit.


https://reviews.llvm.org/D37673

Files:
  lib/Target/X86/X86ISelLowering.cpp


Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -16959,6 +16959,7 @@
 /// Result of 'and' is compared against zero. Change to a BT node if possible.
 static SDValue LowerAndToBT(SDValue And, ISD::CondCode CC,
                             const SDLoc &dl, SelectionDAG &DAG) {
+  assert(And.getOpcode() == ISD::AND && "Expected AND node!");
   SDValue Op0 = And.getOperand(0);
   SDValue Op1 = And.getOperand(1);
   if (Op0.getOpcode() == ISD::TRUNCATE)
@@ -17007,32 +17008,6 @@
   return SDValue();
 }
 
-// Convert (truncate (srl X, N) to i1) to (bt X, N)
-static SDValue LowerTruncateToBT(SDValue Op, ISD::CondCode CC,
-                                 const SDLoc &dl, SelectionDAG &DAG) {
-
-  assert(Op.getOpcode() == ISD::TRUNCATE && Op.getValueType() == MVT::i1 &&
-         "Expected TRUNCATE to i1 node");
-
-  if (Op.getOperand(0).getOpcode() != ISD::SRL)
-    return SDValue();
-
-  SDValue ShiftRight = Op.getOperand(0);
-  return getBitTestCondition(ShiftRight.getOperand(0), ShiftRight.getOperand(1),
-                             CC, dl, DAG);
-}
-
-/// Result of 'and' or 'trunc to i1' is compared against zero.
-/// Change to a BT node if possible.
-SDValue X86TargetLowering::LowerToBT(SDValue Op, ISD::CondCode CC,
-                                     const SDLoc &dl, SelectionDAG &DAG) const {
-  if (Op.getOpcode() == ISD::AND)
-    return LowerAndToBT(Op, CC, dl, DAG);
-  if (Op.getOpcode() == ISD::TRUNCATE && Op.getValueType() == MVT::i1)
-    return LowerTruncateToBT(Op, CC, dl, DAG);
-  return SDValue();
-}
-
 /// Turns an ISD::CondCode into a value suitable for SSE floating-point mask
 /// CMPs.
 static int translateX86FSETCC(ISD::CondCode SetCCOpcode, SDValue &Op0,
@@ -17554,14 +17529,10 @@
   // Lower (X & (1 << N)) == 0 to BT(X, N).
   // Lower ((X >>u N) & 1) != 0 to BT(X, N).
   // Lower ((X >>s N) & 1) != 0 to BT(X, N).
-  // Lower (trunc (X >> N) to i1) to BT(X, N).
-  if (Op0.hasOneUse() && isNullConstant(Op1) &&
+  if (Op0.getOpcode() == ISD::AND && Op0.hasOneUse() && isNullConstant(Op1) &&
       (CC == ISD::SETEQ || CC == ISD::SETNE)) {
-    if (SDValue NewSetCC = LowerToBT(Op0, CC, dl, DAG)) {
-      if (VT == MVT::i1)
-        return DAG.getNode(ISD::TRUNCATE, dl, MVT::i1, NewSetCC);
+    if (SDValue NewSetCC = LowerAndToBT(Op0, CC, dl, DAG))
       return NewSetCC;
-    }
   }
 
   // Look for X == 0, X == 1, X != 0, or X != 1.  We can simplify some forms of
@@ -17935,7 +17906,7 @@
     // We know the result of AND is compared against zero. Try to match
     // it to BT.
     if (Cond.getOpcode() == ISD::AND && Cond.hasOneUse()) {
-      if (SDValue NewSetCC = LowerToBT(Cond, ISD::SETNE, DL, DAG)) {
+      if (SDValue NewSetCC = LowerAndToBT(Cond, ISD::SETNE, DL, DAG)) {
         CC = NewSetCC.getOperand(0);
         Cond = NewSetCC.getOperand(1);
         AddTest = false;
@@ -18790,9 +18761,10 @@
     if (isTruncWithZeroHighBitsInput(Cond, DAG))
         Cond = Cond.getOperand(0);
 
-    // We know the result is compared against zero. Try to match it to BT.
-    if (Cond.hasOneUse()) {
-      if (SDValue NewSetCC = LowerToBT(Cond, ISD::SETNE, dl, DAG)) {
+    // We know the result of AND is compared against zero. Try to match
+    // it to BT.
+    if (Cond.getOpcode() == ISD::AND && Cond.hasOneUse()) {
+      if (SDValue NewSetCC = LowerAndToBT(Cond, ISD::SETNE, dl, DAG)) {
         CC = NewSetCC.getOperand(0);
         Cond = NewSetCC.getOperand(1);
         addTest = false;


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