Make it possible for ints/floats to return different values from getBooleanContents()

Summary:
On MIPS32r6/MIPS64r6, floating point comparisons return 0 or -1 but integer
comparisons return 0 or 1.

Updated the various uses of getBooleanContents. Two simplifications had to be
disabled when float and int boolean contents differ:
- ScalarizeVecRes_VSELECT except when the kind of boolean contents is trivially
  discoverable (i.e. when the condition of the VSELECT is a SETCC node).
- visitVSELECT (select C, 0, 1) -> (xor C, 1).
  Come to think of it, this one could test for the common case of 'C'
  being a SETCC too.

Preserved existing behaviour for all other targets and updated the affected
MIPS32r6/MIPS64r6 tests. This also fixes the pi benchmark where the 'low'
variable was counting in the wrong direction because it thought it could simply
add the result of the comparison.

Reviewers: hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, jholewinski, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D4389

llvm-svn: 212697

1 files changed, 26 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 119b0255e7c..6a3fa7aef1f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1012,11 +1012,12 @@ SDValue SelectionDAG::getZExtOrTrunc(SDValue Op, SDLoc DL, EVT VT) {
     getNode(ISD::TRUNCATE, DL, VT, Op);
 }
 
-SDValue SelectionDAG::getBoolExtOrTrunc(SDValue Op, SDLoc SL, EVT VT) {
+SDValue SelectionDAG::getBoolExtOrTrunc(SDValue Op, SDLoc SL, EVT VT,
+                                        EVT OpVT) {
   if (VT.bitsLE(Op.getValueType()))
     return getNode(ISD::TRUNCATE, SL, VT, Op);
 
-  TargetLowering::BooleanContent BType = TLI->getBooleanContents(VT.isVector());
+  TargetLowering::BooleanContent BType = TLI->getBooleanContents(OpVT);
   return getNode(TLI->getExtendForContent(BType), SL, VT, Op);
 }
 
@@ -1054,7 +1055,7 @@ SDValue SelectionDAG::getNOT(SDLoc DL, SDValue Val, EVT VT) {
 SDValue SelectionDAG::getLogicalNOT(SDLoc DL, SDValue Val, EVT VT) {
   EVT EltVT = VT.getScalarType();
   SDValue TrueValue;
-  switch (TLI->getBooleanContents(VT.isVector())) {
+  switch (TLI->getBooleanContents(VT)) {
     case TargetLowering::ZeroOrOneBooleanContent:
     case TargetLowering::UndefinedBooleanContent:
       TrueValue = getConstant(1, VT);
@@ -1776,7 +1777,8 @@ SDValue SelectionDAG::FoldSetCC(EVT VT, SDValue N1,
   case ISD::SETTRUE:
   case ISD::SETTRUE2: {
     const TargetLowering *TLI = TM.getTargetLowering();
-    TargetLowering::BooleanContent Cnt = TLI->getBooleanContents(VT.isVector());
+    TargetLowering::BooleanContent Cnt =
+        TLI->getBooleanContents(N1->getValueType(0));
     return getConstant(
         Cnt == TargetLowering::ZeroOrNegativeOneBooleanContent ? -1ULL : 1, VT);
   }
@@ -2007,11 +2009,20 @@ void SelectionDAG::computeKnownBits(SDValue Op, APInt &KnownZero,
   case ISD::UMULO:
     if (Op.getResNo() != 1)
       break;
-    // The boolean result conforms to getBooleanContents.  Fall through.
+    // The boolean result conforms to getBooleanContents.
+    // If we know the result of a setcc has the top bits zero, use this info.
+    // We know that we have an integer-based boolean since these operations
+    // are only available for integer.
+    if (TLI->getBooleanContents(Op.getValueType().isVector(), false) ==
+            TargetLowering::ZeroOrOneBooleanContent &&
+        BitWidth > 1)
+      KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - 1);
+    break;
   case ISD::SETCC:
     // If we know the result of a setcc has the top bits zero, use this info.
-    if (TLI->getBooleanContents(Op.getValueType().isVector()) ==
-        TargetLowering::ZeroOrOneBooleanContent && BitWidth > 1)
+    if (TLI->getBooleanContents(Op.getOperand(0).getValueType()) ==
+            TargetLowering::ZeroOrOneBooleanContent &&
+        BitWidth > 1)
       KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - 1);
     break;
   case ISD::SHL:
@@ -2410,9 +2421,16 @@ unsigned SelectionDAG::ComputeNumSignBits(SDValue Op, unsigned Depth) const{
     if (Op.getResNo() != 1)
       break;
     // The boolean result conforms to getBooleanContents.  Fall through.
+    // If setcc returns 0/-1, all bits are sign bits.
+    // We know that we have an integer-based boolean since these operations
+    // are only available for integer.
+    if (TLI->getBooleanContents(Op.getValueType().isVector(), false) ==
+        TargetLowering::ZeroOrNegativeOneBooleanContent)
+      return VTBits;
+    break;
   case ISD::SETCC:
     // If setcc returns 0/-1, all bits are sign bits.
-    if (TLI->getBooleanContents(Op.getValueType().isVector()) ==
+    if (TLI->getBooleanContents(Op.getOperand(0).getValueType()) ==
         TargetLowering::ZeroOrNegativeOneBooleanContent)
       return VTBits;
     break;