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authorStephen Hines <srhines@google.com>2012-08-23 19:08:53 -0700
committerStephen Hines <srhines@google.com>2012-08-23 19:08:53 -0700
commit31675153bd2d7617db8cb6aeb58054934c7b9f73 (patch)
treec1970fcebc736d4f731db0559a79a7ac5cb0f8bf /lib/Support/APFloat.cpp
parent416bb6a168a9316547db6ce3909c515f70a84f52 (diff)
parent75dd7f0c4a2b3fb9e9d4d5a0517591810c57ed92 (diff)
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Merge branch 'upstream' into merge_2
Conflicts: lib/Target/ARM/ARMCodeEmitter.cpp Change-Id: I6702d340c733e9721499b5d85b13b96ad9c14eb5
Diffstat (limited to 'lib/Support/APFloat.cpp')
-rw-r--r--lib/Support/APFloat.cpp56
1 files changed, 46 insertions, 10 deletions
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 409d4fb..ed261a4 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -1765,6 +1765,50 @@ APFloat::fusedMultiplyAdd(const APFloat &multiplicand,
return fs;
}
+/* Rounding-mode corrrect round to integral value. */
+APFloat::opStatus APFloat::roundToIntegral(roundingMode rounding_mode) {
+ opStatus fs;
+ assertArithmeticOK(*semantics);
+
+ // If the exponent is large enough, we know that this value is already
+ // integral, and the arithmetic below would potentially cause it to saturate
+ // to +/-Inf. Bail out early instead.
+ if (exponent+1 >= (int)semanticsPrecision(*semantics))
+ return opOK;
+
+ // The algorithm here is quite simple: we add 2^(p-1), where p is the
+ // precision of our format, and then subtract it back off again. The choice
+ // of rounding modes for the addition/subtraction determines the rounding mode
+ // for our integral rounding as well.
+ // NOTE: When the input value is negative, we do subtraction followed by
+ // addition instead.
+ APInt IntegerConstant(NextPowerOf2(semanticsPrecision(*semantics)), 1);
+ IntegerConstant <<= semanticsPrecision(*semantics)-1;
+ APFloat MagicConstant(*semantics);
+ fs = MagicConstant.convertFromAPInt(IntegerConstant, false,
+ rmNearestTiesToEven);
+ MagicConstant.copySign(*this);
+
+ if (fs != opOK)
+ return fs;
+
+ // Preserve the input sign so that we can handle 0.0/-0.0 cases correctly.
+ bool inputSign = isNegative();
+
+ fs = add(MagicConstant, rounding_mode);
+ if (fs != opOK && fs != opInexact)
+ return fs;
+
+ fs = subtract(MagicConstant, rounding_mode);
+
+ // Restore the input sign.
+ if (inputSign != isNegative())
+ changeSign();
+
+ return fs;
+}
+
+
/* Comparison requires normalized numbers. */
APFloat::cmpResult
APFloat::compare(const APFloat &rhs) const
@@ -3278,16 +3322,8 @@ APFloat::APFloat(double d) : exponent2(0), sign2(0) {
}
namespace {
- static void append(SmallVectorImpl<char> &Buffer,
- unsigned N, const char *Str) {
- unsigned Start = Buffer.size();
- Buffer.set_size(Start + N);
- memcpy(&Buffer[Start], Str, N);
- }
-
- template <unsigned N>
- void append(SmallVectorImpl<char> &Buffer, const char (&Str)[N]) {
- append(Buffer, N, Str);
+ void append(SmallVectorImpl<char> &Buffer, StringRef Str) {
+ Buffer.append(Str.begin(), Str.end());
}
/// Removes data from the given significand until it is no more