[ConstantRange] Optimize APInt creation in getSignedMax/getSignedMin.
We were creating an APInt at the top of these methods that isn't always returned. For ranges wider than 64-bits this results in an allocation and deallocation when its not used.
In getSignedMax we were creating Upper-1 to use in a compare and then creating it again for a return value. The compiler is unable to determine that these can be shared. So help it out and create the Upper-1 in a temporary that can be reused.
This provides a little compile time improvement.
llvm-svn: 300621
diff --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp
index c1c83cc..0cc38b0 100644
--- a/llvm/lib/IR/ConstantRange.cpp
+++ b/llvm/lib/IR/ConstantRange.cpp
@@ -281,25 +281,25 @@
APInt ConstantRange::getSignedMax() const {
APInt SignedMax(APInt::getSignedMaxValue(getBitWidth()));
if (!isWrappedSet()) {
- if (getLower().sle(getUpper() - 1))
- return getUpper() - 1;
- return SignedMax;
+ APInt UpperMinusOne = getUpper() - 1;
+ if (getLower().sle(UpperMinusOne))
+ return UpperMinusOne;
+ return APInt::getSignedMaxValue(getBitWidth());
}
if (getLower().isNegative() == getUpper().isNegative())
- return SignedMax;
+ return APInt::getSignedMaxValue(getBitWidth());
return getUpper() - 1;
}
APInt ConstantRange::getSignedMin() const {
- APInt SignedMin(APInt::getSignedMinValue(getBitWidth()));
if (!isWrappedSet()) {
if (getLower().sle(getUpper() - 1))
return getLower();
- return SignedMin;
+ return APInt::getSignedMinValue(getBitWidth());
}
if ((getUpper() - 1).slt(getLower())) {
- if (getUpper() != SignedMin)
- return SignedMin;
+ if (!getUpper().isMinSignedValue())
+ return APInt::getSignedMinValue(getBitWidth());
}
return getLower();
}