[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

1 files changed, 5 insertions, 6 deletions

diff --git a/llvm/lib/Support/APInt.cpp b/llvm/lib/Support/APInt.cpp
index 4a136f7..caa0691 100644
--- a/llvm/lib/Support/APInt.cpp
+++ b/llvm/lib/Support/APInt.cpp
@@ -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;