commit f3dbd17d0a9f286591026a01a026aceec92dcfb7
author Craig Topper <craig.topper@gmail.com> Tue Apr 25 17:46:30 2017 +0000
committer Craig Topper <craig.topper@gmail.com> Tue Apr 25 17:46:30 2017 +0000
tree ff5f538dbc45c42146175a03b37dbbde80a7e949
parent b3b3c29c875af3246231dd8b2d4b9aade66c1b6c

[APInt] Use isSubsetOf, intersects, and bit counting methods to reduce temporary APInts

This patch uses various APInt methods to reduce temporary APInt creation.

This should be all of the unrelated cleanups that got buried in D32376(creating a KnownBits struct) as well as some pointed out by Simon during the review of that. Plus a few improvements to use counting instead of masking.

I've left out any places where we do something like (KnownZero & KnownOne) != 0 as I plan to add a helper method to KnownBits to ask that question and didn't want to thrash that code an additional time.

Differential Revision: https://reviews.llvm.org/D32495

llvm-svn: 301338

llvm/lib/Analysis/InstructionSimplify.cpp

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index febaf30..5670746 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1376,8 +1376,7 @@
   // If all valid bits in the shift amount are known zero, the first operand is
   // unchanged.
   unsigned NumValidShiftBits = Log2_32_Ceil(BitWidth);
-  APInt ShiftAmountMask = APInt::getLowBitsSet(BitWidth, NumValidShiftBits);
-  if ((KnownZero & ShiftAmountMask) == ShiftAmountMask)
+  if (KnownZero.countTrailingOnes() >= NumValidShiftBits)
     return Op0;
 
   return nullptr;
@@ -3372,7 +3371,7 @@
       APInt LHSKnownOne(BitWidth, 0);
       computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL, /*Depth=*/0, Q.AC,
                        Q.CxtI, Q.DT);
-      if (((LHSKnownZero & *RHSVal) != 0) || ((LHSKnownOne & ~(*RHSVal)) != 0))
+      if (LHSKnownZero.intersects(*RHSVal) || !LHSKnownOne.isSubsetOf(*RHSVal))
         return Pred == ICmpInst::ICMP_EQ ? ConstantInt::getFalse(ITy)
                                          : ConstantInt::getTrue(ITy);
     }

llvm/lib/Analysis/ValueTracking.cpp

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 02db651..b39783d 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1934,12 +1934,12 @@
       // The sign bit of X is set.  If some other bit is set then X is not equal
       // to INT_MIN.
       computeKnownBits(X, KnownZero, KnownOne, Depth, Q);
-      if ((KnownOne & Mask) != 0)
+      if (KnownOne.intersects(Mask))
         return true;
       // The sign bit of Y is set.  If some other bit is set then Y is not equal
       // to INT_MIN.
       computeKnownBits(Y, KnownZero, KnownOne, Depth, Q);
-      if ((KnownOne & Mask) != 0)
+      if (KnownOne.intersects(Mask))
         return true;
     }
 
@@ -2056,7 +2056,7 @@
                        const Query &Q) {
   APInt KnownZero(Mask.getBitWidth(), 0), KnownOne(Mask.getBitWidth(), 0);
   computeKnownBits(V, KnownZero, KnownOne, Depth, Q);
-  return (KnownZero & Mask) == Mask;
+  return Mask.isSubsetOf(KnownZero);
 }
 
 /// For vector constants, loop over the elements and find the constant with the
@@ -4289,7 +4289,7 @@
         APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
         computeKnownBits(X, KnownZero, KnownOne, DL, Depth + 1, AC, CxtI, DT);
 
-        if ((KnownZero & *CA) == *CA && (KnownZero & *CB) == *CB)
+        if (CA->isSubsetOf(KnownZero) && CB->isSubsetOf(KnownZero))
           return true;
       }