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[APInt] Modify tcMultiplyPart's overflow detection to not depend on 'i' from the earlier loop. NFC 

The value of 'i' is always the smaller of DstParts and SrcParts so we can just use that fact to write all the code in terms of SrcParts and DstParts.

llvm-svn: 302408
This commit is contained in:
Craig Topper 2017-05-08 06:34:41 +00:00
parent 0cbab7cc7a
commit c96a84d813
1 changed files with 5 additions and 6 deletions
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11
llvm/lib/Support/APInt.cpp
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@ -2254,8 +2254,7 @@ int APInt::tcMultiplyPart(WordType *dst, const WordType *src,
/* N loops; minimum of dstParts and srcParts. */
unsigned n = std::min(dstParts, srcParts);
unsigned i;
for (i = 0; i < n; i++) {
for (unsigned i = 0; i < n; i++) {
WordType low, mid, high, srcPart;
/* [ LOW, HIGH ] = MULTIPLIER * SRC[i] + DST[i] + CARRY.
@ -2306,10 +2305,10 @@ int APInt::tcMultiplyPart(WordType *dst, const WordType *src,
carry = high;
}
if (i < dstParts) {
if (srcParts < dstParts) {
/* Full multiplication, there is no overflow. */
assert(i + 1 == dstParts);
dst[i] = carry;
assert(srcParts + 1 == dstParts);
dst[srcParts] = carry;
return 0;
}
@ -2321,7 +2320,7 @@ int APInt::tcMultiplyPart(WordType *dst, const WordType *src,
non-zero. This is true if any remaining src parts are non-zero
and the multiplier is non-zero. */
if (multiplier)
for (; i < srcParts; i++)
for (unsigned i = dstParts; i < srcParts; i++)
if (src[i])
return 1;