Generalize tcFullMultiply so that the operands can be of differing
part widths. Also, return the number of parts actually required to
hold the result's value.
Remove an over-cautious condition from rounding of float->hex conversion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42669 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index 63bde6c..e7b7c1f 100644
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -2363,25 +2363,32 @@
return overflow;
}
-/* DST = LHS * RHS, where DST has twice the width as the operands. No
- overflow occurs. DST must be disjoint from both operands. */
-void
+/* DST = LHS * RHS, where DST has width the sum of the widths of the
+ operands. No overflow occurs. DST must be disjoint from both
+ operands. Returns the number of parts required to hold the
+ result. */
+unsigned int
APInt::tcFullMultiply(integerPart *dst, const integerPart *lhs,
- const integerPart *rhs, unsigned int parts)
+ const integerPart *rhs, unsigned int lhsParts,
+ unsigned int rhsParts)
{
- unsigned int i;
- int overflow;
+ /* Put the narrower number on the LHS for less loops below. */
+ if (lhsParts > rhsParts) {
+ return tcFullMultiply (dst, rhs, lhs, rhsParts, lhsParts);
+ } else {
+ unsigned int n;
- assert(dst != lhs && dst != rhs);
+ assert(dst != lhs && dst != rhs);
- overflow = 0;
- tcSet(dst, 0, parts);
+ tcSet(dst, 0, rhsParts);
- for(i = 0; i < parts; i++)
- overflow |= tcMultiplyPart(&dst[i], lhs, rhs[i], 0, parts,
- parts + 1, true);
+ for(n = 0; n < lhsParts; n++)
+ tcMultiplyPart(&dst[n], rhs, lhs[n], 0, rhsParts, rhsParts + 1, true);
- assert(!overflow);
+ n = lhsParts + rhsParts;
+
+ return n - (dst[n - 1] == 0);
+ }
}
/* If RHS is zero LHS and REMAINDER are left unchanged, return one.