Changes in directory llvm/lib/Support:
APInt.cpp updated: 1.52 -> 1.53
---
Log message:
1. Fix three serious bugs in the comparison code.
2. Change RoundDoubleToAPInt to take a bit width parameter. Use that
parameter to limit the bit width of the result.
---
Diffs of the changes: (+22 -18)
APInt.cpp | 40 ++++++++++++++++++++++------------------
1 files changed, 22 insertions(+), 18 deletions(-)
Index: llvm/lib/Support/APInt.cpp
diff -u llvm/lib/Support/APInt.cpp:1.52 llvm/lib/Support/APInt.cpp:1.53
--- llvm/lib/Support/APInt.cpp:1.52 Tue Feb 27 01:35:18 2007
+++ llvm/lib/Support/APInt.cpp Tue Feb 27 12:23:40 2007
@@ -540,7 +540,8 @@
return pVal[0] < RHS.pVal[0];
// Otherwise, compare all words
- for (int i = whichWord(n1 - 1); i >= 0; --i) {
+ uint32_t topWord = whichWord(std::max(n1,n2)-1);
+ for (int i = topWord; i >= 0; --i) {
if (pVal[i] > RHS.pVal[i])
return false;
if (pVal[i] < RHS.pVal[i])
@@ -558,30 +559,28 @@
}
APInt lhs(*this);
- APInt rhs(*this);
- bool lhsNegative = false;
- bool rhsNegative = false;
- if (lhs[BitWidth-1]) {
- // Sign bit is set so make a note of it and perform two's complement
- lhsNegative = true;
+ APInt rhs(RHS);
+ bool lhsNeg = isNegative();
+ bool rhsNeg = rhs.isNegative();
+ if (lhsNeg) {
+ // Sign bit is set so perform two's complement to make it positive
lhs.flip();
lhs++;
}
- if (rhs[BitWidth-1]) {
- // Sign bit is set so make a note of it and perform two's complement
- rhsNegative = true;
+ if (rhsNeg) {
+ // Sign bit is set so perform two's complement to make it positive
rhs.flip();
rhs++;
}
// Now we have unsigned values to compare so do the comparison if necessary
// based on the negativeness of the values.
- if (lhsNegative)
- if (rhsNegative)
- return !lhs.ult(rhs);
+ if (lhsNeg)
+ if (rhsNeg)
+ return lhs.ugt(rhs);
else
return true;
- else if (rhsNegative)
+ else if (rhsNeg)
return false;
else
return lhs.ult(rhs);
@@ -797,7 +796,7 @@
return A;
}
-APInt llvm::APIntOps::RoundDoubleToAPInt(double Double) {
+APInt llvm::APIntOps::RoundDoubleToAPInt(double Double, uint32_t width) {
union {
double D;
uint64_t I;
@@ -819,11 +818,16 @@
// If the exponent doesn't shift all bits out of the mantissa
if (exp < 52)
- return isNeg ? -APInt(64u, mantissa >> (52 - exp)) :
- APInt(64u, mantissa >> (52 - exp));
+ return isNeg ? -APInt(width, mantissa >> (52 - exp)) :
+ APInt(width, mantissa >> (52 - exp));
+
+ // If the client didn't provide enough bits for us to shift the mantissa into
+ // then the result is undefined, just return 0
+ if (width <= exp - 52)
+ return APInt(width, 0);
// Otherwise, we have to shift the mantissa bits up to the right location
- APInt Tmp(exp+1, mantissa);
+ APInt Tmp(width, mantissa);
Tmp = Tmp.shl(exp - 52);
return isNeg ? -Tmp : Tmp;
}
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