1 files changed, 57 insertions, 0 deletions
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 6a264fdfc4..5f4b4365fd 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -3990,3 +3990,60 @@ ARMTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
   // The ARM target isn't yet aware of offsets.
   return false;
 }
+
+int ARM::getVFPf32Imm(const APFloat &FPImm) {
+  APInt Imm = FPImm.bitcastToAPInt();
+  uint32_t Sign = Imm.lshr(31).getZExtValue() & 1;
+  int32_t Exp = (Imm.lshr(23).getSExtValue() & 0xff) - 127;  // -126 to 127
+  int64_t Mantissa = Imm.getZExtValue() & 0x7fffff;  // 23 bits
+
+  // We can handle 4 bits of mantissa.
+  // mantissa = (16+UInt(e:f:g:h))/16.
+  if (Mantissa & 0x7ffff)
+    return -1;
+  Mantissa >>= 19;
+  if ((Mantissa & 0xf) != Mantissa)
+    return -1;
+
+  // We can handle 3 bits of exponent: exp == UInt(NOT(b):c:d)-3
+  if (Exp < -3 || Exp > 4)
+    return -1;
+  Exp = ((Exp+3) & 0x7) ^ 4;
+
+  return ((int)Sign << 7) | (Exp << 4) | Mantissa;
+}
+
+int ARM::getVFPf64Imm(const APFloat &FPImm) {
+  APInt Imm = FPImm.bitcastToAPInt();
+  uint64_t Sign = Imm.lshr(63).getZExtValue() & 1;
+  int64_t Exp = (Imm.lshr(52).getSExtValue() & 0x7ff) - 1023;   // -1022 to 1023
+  uint64_t Mantissa = Imm.getZExtValue() & 0xfffffffffffffLL;
+
+  // We can handle 4 bits of mantissa.
+  // mantissa = (16+UInt(e:f:g:h))/16.
+  if (Mantissa & 0xffffffffffffLL)
+    return -1;
+  Mantissa >>= 48;
+  if ((Mantissa & 0xf) != Mantissa)
+    return -1;
+
+  // We can handle 3 bits of exponent: exp == UInt(NOT(b):c:d)-3
+  if (Exp < -3 || Exp > 4)
+    return -1;
+  Exp = ((Exp+3) & 0x7) ^ 4;
+
+  return ((int)Sign << 7) | (Exp << 4) | Mantissa;
+}
+
+/// isFPImmLegal - Returns true if the target can instruction select the
+/// specified FP immediate natively. If false, the legalizer will
+/// materialize the FP immediate as a load from a constant pool.
+bool ARMTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT) const {
+  if (!Subtarget->hasVFP3())
+    return false;
+  if (VT == MVT::f32)
+    return ARM::getVFPf32Imm(Imm) != -1;
+  if (VT == MVT::f64)
+    return ARM::getVFPf64Imm(Imm) != -1;
+  return false;
+}