[llvm-commits] CVS: llvm/lib/Support/APInt.cpp

[Reid Spencer]

Changes in directory llvm/lib/Support:

APInt.cpp updated: 1.64 -> 1.65
---
Log message:

Fix a problem where shifting by 64-bits leads to incorrect results on PPC
but not on X86 becuase shift by word size is "undefined".


---
Diffs of the changes:  (+4 -1)

 APInt.cpp |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)


Index: llvm/lib/Support/APInt.cpp
diff -u llvm/lib/Support/APInt.cpp:1.64 llvm/lib/Support/APInt.cpp:1.65
--- llvm/lib/Support/APInt.cpp:1.64	Thu Mar  1 17:30:25 2007
+++ llvm/lib/Support/APInt.cpp	Thu Mar  1 19:19:42 2007
@@ -938,7 +938,10 @@
   if (wordsBefore == wordsAfter) {
     uint32_t newWordBits = width % APINT_BITS_PER_WORD;
     // The extension is contained to the wordsBefore-1th word.
-    uint64_t mask = (~0ULL >> (APINT_BITS_PER_WORD - newWordBits)) <<  wordBits;
+    uint64_t mask = ~0ULL;
+    if (newWordBits)
+      mask >>= APINT_BITS_PER_WORD - newWordBits;
+    mask <<= wordBits;
     if (wordsBefore == 1)
       VAL |= mask;
     else