[llvm] r300812 - [APInt] Implement APInt::intersects without creating a temporary APInt in the multiword case
Craig Topper via llvm-commits
llvm-commits at lists.llvm.org
Wed Apr 19 19:11:27 PDT 2017
Author: ctopper
Date: Wed Apr 19 21:11:27 2017
New Revision: 300812
URL: http://llvm.org/viewvc/llvm-project?rev=300812&view=rev
Log:
[APInt] Implement APInt::intersects without creating a temporary APInt in the multiword case
Summary: This is a simple question we should be able to answer without creating a temporary to hold the AND result. We can also get an early out as soon as we find a word that intersects.
Reviewers: RKSimon, hans, spatel, davide
Reviewed By: hans, davide
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32253
Modified:
llvm/trunk/include/llvm/ADT/APInt.h
llvm/trunk/lib/Support/APInt.cpp
Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=300812&r1=300811&r2=300812&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Wed Apr 19 21:11:27 2017
@@ -209,6 +209,9 @@ private:
/// out-of-line slow case for countPopulation
unsigned countPopulationSlowCase() const LLVM_READONLY;
+ /// out-of-line slow case for intersects.
+ bool intersectsSlowCase(const APInt &RHS) const LLVM_READONLY;
+
/// out-of-line slow case for setBits.
void setBitsSlowCase(unsigned loBit, unsigned hiBit);
@@ -1206,9 +1209,10 @@ public:
/// This operation tests if there are any pairs of corresponding bits
/// between this APInt and RHS that are both set.
bool intersects(const APInt &RHS) const {
- APInt temp(*this);
- temp &= RHS;
- return temp != 0;
+ assert(BitWidth == RHS.BitWidth && "Bit widths must be the same");
+ if (isSingleWord())
+ return (VAL & RHS.VAL) != 0;
+ return intersectsSlowCase(RHS);
}
/// @}
Modified: llvm/trunk/lib/Support/APInt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APInt.cpp?rev=300812&r1=300811&r2=300812&view=diff
==============================================================================
--- llvm/trunk/lib/Support/APInt.cpp (original)
+++ llvm/trunk/lib/Support/APInt.cpp Wed Apr 19 21:11:27 2017
@@ -722,6 +722,14 @@ unsigned APInt::countPopulationSlowCase(
return Count;
}
+bool APInt::intersectsSlowCase(const APInt &RHS) const {
+ for (unsigned i = 0, e = getNumWords(); i != e; ++i)
+ if ((pVal[i] & RHS.pVal[i]) != 0)
+ return true;
+
+ return false;
+}
+
APInt APInt::byteSwap() const {
assert(BitWidth >= 16 && BitWidth % 16 == 0 && "Cannot byteswap!");
if (BitWidth == 16)
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