Add an APFloat::convertToInt(APSInt) function that automatically manages the

memory for the result.

llvm-svn: 135259

include/llvm/ADT/APFloat.h

@@ -109,6 +109,7 @@ namespace llvm {
   typedef signed short exponent_t;
 
   struct fltSemantics;
+  class APSInt;
   class StringRef;
 
   /* When bits of a floating point number are truncated, this enum is
@@ -283,6 +284,7 @@ namespace llvm {
     opStatus convert(const fltSemantics &, roundingMode, bool *);
     opStatus convertToInteger(integerPart *, unsigned int, bool,
                               roundingMode, bool *) const;
+    opStatus convertToInteger(APSInt&, roundingMode, bool *) const;
     opStatus convertFromAPInt(const APInt &,
                               bool, roundingMode);
     opStatus convertFromSignExtendedInteger(const integerPart *, unsigned int,

lib/Support/APFloat.cpp

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -2084,6 +2085,23 @@ APFloat::convertToInteger(integerPart *parts, unsigned int width,
   return fs;
 }
 
+/* Same as convertToInteger(integerPart*, ...), except the result is returned in
+   an APSInt, whose initial bit-width and signed-ness are used to determine the
+   precision of the conversion.
+ */
+APFloat::opStatus
+APFloat::convertToInteger(APSInt &result,
+                          roundingMode rounding_mode, bool *isExact) const
+{
+  unsigned bitWidth = result.getBitWidth();
+  SmallVector<uint64_t, 4> parts(result.getNumWords());
+  opStatus status = convertToInteger(
+    parts.data(), bitWidth, result.isSigned(), rounding_mode, isExact);
+  // Keeps the original signed-ness.
+  result = APInt(bitWidth, parts.size(), parts.data());
+  return status;
+}
+
 /* Convert an unsigned integer SRC to a floating point number,
    rounding according to ROUNDING_MODE.  The sign of the floating
    point number is not modified.  */

unittests/ADT/APFloatTest.cpp

@@ -12,6 +12,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 #include "llvm/ADT/APFloat.h"
+#include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 
@@ -344,6 +345,54 @@ TEST(APFloatTest, toString) {
   ASSERT_EQ("8.731834E+2", convertToString(873.1834, 0, 0));
 }
 
+TEST(APFloatTest, toInteger) {
+  bool isExact = false;
+  APSInt result(5, /*isUnsigned=*/true);
+
+  EXPECT_EQ(APFloat::opOK,
+            APFloat(APFloat::IEEEdouble, "10")
+            .convertToInteger(result, APFloat::rmTowardZero, &isExact));
+  EXPECT_TRUE(isExact);
+  EXPECT_EQ(APSInt(APInt(5, 10), true), result);
+
+  EXPECT_EQ(APFloat::opInvalidOp,
+            APFloat(APFloat::IEEEdouble, "-10")
+            .convertToInteger(result, APFloat::rmTowardZero, &isExact));
+  EXPECT_FALSE(isExact);
+  EXPECT_EQ(APSInt::getMinValue(5, true), result);
+
+  EXPECT_EQ(APFloat::opInvalidOp,
+            APFloat(APFloat::IEEEdouble, "32")
+            .convertToInteger(result, APFloat::rmTowardZero, &isExact));
+  EXPECT_FALSE(isExact);
+  EXPECT_EQ(APSInt::getMaxValue(5, true), result);
+
+  EXPECT_EQ(APFloat::opInexact,
+            APFloat(APFloat::IEEEdouble, "7.9")
+            .convertToInteger(result, APFloat::rmTowardZero, &isExact));
+  EXPECT_FALSE(isExact);
+  EXPECT_EQ(APSInt(APInt(5, 7), true), result);
+
+  result.setIsUnsigned(false);
+  EXPECT_EQ(APFloat::opOK,
+            APFloat(APFloat::IEEEdouble, "-10")
+            .convertToInteger(result, APFloat::rmTowardZero, &isExact));
+  EXPECT_TRUE(isExact);
+  EXPECT_EQ(APSInt(APInt(5, -10, true), false), result);
+
+  EXPECT_EQ(APFloat::opInvalidOp,
+            APFloat(APFloat::IEEEdouble, "-17")
+            .convertToInteger(result, APFloat::rmTowardZero, &isExact));
+  EXPECT_FALSE(isExact);
+  EXPECT_EQ(APSInt::getMinValue(5, false), result);
+
+  EXPECT_EQ(APFloat::opInvalidOp,
+            APFloat(APFloat::IEEEdouble, "16")
+            .convertToInteger(result, APFloat::rmTowardZero, &isExact));
+  EXPECT_FALSE(isExact);
+  EXPECT_EQ(APSInt::getMaxValue(5, false), result);
+}
+
 static APInt nanbits(const fltSemantics &Sem,
                      bool SNaN, bool Negative, uint64_t fill) {
   APInt apfill(64, fill);