[APInt.h] Reduce the APInt header file interface a bit. NFC

This moves one mid-size function out of line, inlines the
trivial tcAnd/tcOr/tcXor/tcComplement methods into their only
caller, and moves the magic/umagic functions into SelectionDAG
since they are implementation details of its algorithm. This
also removes the unit tests for magic, but these are already
tested in the divide lowering logic for various targets.

This also upgrades some C style comments to C++.

Differential Revision: https://reviews.llvm.org/D109476

1 files changed, 20 insertions, 3 deletions

diff --git a/llvm/lib/Support/APFloat.cpp b/llvm/lib/Support/APFloat.cpp
index 7abca83..c9ecd5a 100644
--- a/llvm/lib/Support/APFloat.cpp
+++ b/llvm/lib/Support/APFloat.cpp
@@ -1288,6 +1288,23 @@ IEEEFloat::compareAbsoluteValue(const IEEEFloat &rhs) const {
     return cmpEqual;
 }
 
+/* Set the least significant BITS bits of a bignum, clear the
+   rest.  */
+static void tcSetLeastSignificantBits(APInt::WordType *dst, unsigned parts,
+                                      unsigned bits) {
+  unsigned i = 0;
+  while (bits > APInt::APINT_BITS_PER_WORD) {
+    dst[i++] = ~(APInt::WordType)0;
+    bits -= APInt::APINT_BITS_PER_WORD;
+  }
+
+  if (bits)
+    dst[i++] = ~(APInt::WordType)0 >> (APInt::APINT_BITS_PER_WORD - bits);
+
+  while (i < parts)
+    dst[i++] = 0;
+}
+
 /* Handle overflow.  Sign is preserved.  We either become infinity or
    the largest finite number.  */
 IEEEFloat::opStatus IEEEFloat::handleOverflow(roundingMode rounding_mode) {
@@ -1303,8 +1320,8 @@ IEEEFloat::opStatus IEEEFloat::handleOverflow(roundingMode rounding_mode) {
   /* Otherwise we become the largest finite number.  */
   category = fcNormal;
   exponent = semantics->maxExponent;
-  APInt::tcSetLeastSignificantBits(significandParts(), partCount(),
-                                   semantics->precision);
+  tcSetLeastSignificantBits(significandParts(), partCount(),
+                            semantics->precision);
 
   return opInexact;
 }
@@ -2412,7 +2429,7 @@ IEEEFloat::convertToInteger(MutableArrayRef<integerPart> parts,
     else
       bits = width - isSigned;
 
-    APInt::tcSetLeastSignificantBits(parts.data(), dstPartsCount, bits);
+    tcSetLeastSignificantBits(parts.data(), dstPartsCount, bits);
     if (sign && isSigned)
       APInt::tcShiftLeft(parts.data(), dstPartsCount, width - 1);
   }