[InstCombine] Change the interface of SimplifyDemandedBits so that it takes the instruction and operand instead of the Use.

The first thing it did was get the User for the Use to get the instruction back. This requires looking through the Uses for the User using the waymarking walk. That's pretty fast, but its probably still better to just pass the Instruction we already had.

llvm-svn: 298772

1 files changed, 42 insertions, 43 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 41d4a4820bf..09069464bb0 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -68,12 +68,13 @@ bool InstCombiner::SimplifyDemandedInstructionBits(Instruction &Inst) {
 /// This form of SimplifyDemandedBits simplifies the specified instruction
 /// operand if possible, updating it in place. It returns true if it made any
 /// change and false otherwise.
-bool InstCombiner::SimplifyDemandedBits(Use &U, const APInt &DemandedMask,
+bool InstCombiner::SimplifyDemandedBits(Instruction *I, unsigned OpNo,
+                                        const APInt &DemandedMask,
                                         APInt &KnownZero, APInt &KnownOne,
                                         unsigned Depth) {
-  auto *UserI = dyn_cast<Instruction>(U.getUser());
+  Use &U = I->getOperandUse(OpNo);
   Value *NewVal = SimplifyDemandedUseBits(U.get(), DemandedMask, KnownZero,
-                                          KnownOne, Depth, UserI);
+                                          KnownOne, Depth, I);
   if (!NewVal) return false;
   U = NewVal;
   return true;
@@ -242,10 +243,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     break;
   case Instruction::And:
     // If either the LHS or the RHS are Zero, the result is zero.
-    if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, RHSKnownZero,
-                             RHSKnownOne, Depth + 1) ||
-        SimplifyDemandedBits(I->getOperandUse(0), DemandedMask & ~RHSKnownZero,
-                             LHSKnownZero, LHSKnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 1, DemandedMask, RHSKnownZero, RHSKnownOne,
+                             Depth + 1) ||
+        SimplifyDemandedBits(I, 0, DemandedMask & ~RHSKnownZero, LHSKnownZero,
+                             LHSKnownOne, Depth + 1))
       return I;
     assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?");
     assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?");
@@ -280,10 +281,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     break;
   case Instruction::Or:
     // If either the LHS or the RHS are One, the result is One.
-    if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, RHSKnownZero,
-                             RHSKnownOne, Depth + 1) ||
-        SimplifyDemandedBits(I->getOperandUse(0), DemandedMask & ~RHSKnownOne,
-                             LHSKnownZero, LHSKnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 1, DemandedMask, RHSKnownZero, RHSKnownOne,
+                             Depth + 1) ||
+        SimplifyDemandedBits(I, 0, DemandedMask & ~RHSKnownOne, LHSKnownZero,
+                             LHSKnownOne, Depth + 1))
       return I;
     assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?");
     assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?");
@@ -322,10 +323,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     KnownOne = RHSKnownOne | LHSKnownOne;
     break;
   case Instruction::Xor: {
-    if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, RHSKnownZero,
-                             RHSKnownOne, Depth + 1) ||
-        SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, LHSKnownZero,
-                             LHSKnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 1, DemandedMask, RHSKnownZero, RHSKnownOne,
+                             Depth + 1) ||
+        SimplifyDemandedBits(I, 0, DemandedMask, LHSKnownZero, LHSKnownOne,
+                             Depth + 1))
       return I;
     assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?");
     assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?");
@@ -415,10 +416,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     if (matchSelectPattern(I, LHS, RHS).Flavor != SPF_UNKNOWN)
       return nullptr;
 
-    if (SimplifyDemandedBits(I->getOperandUse(2), DemandedMask, RHSKnownZero,
-                             RHSKnownOne, Depth + 1) ||
-        SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, LHSKnownZero,
-                             LHSKnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 2, DemandedMask, RHSKnownZero, RHSKnownOne,
+                             Depth + 1) ||
+        SimplifyDemandedBits(I, 1, DemandedMask, LHSKnownZero, LHSKnownOne,
+                             Depth + 1))
       return I;
     assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?");
     assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?");
@@ -437,8 +438,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     DemandedMask = DemandedMask.zext(truncBf);
     KnownZero = KnownZero.zext(truncBf);
     KnownOne = KnownOne.zext(truncBf);
-    if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, KnownZero,
-                             KnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 0, DemandedMask, KnownZero, KnownOne,
+                             Depth + 1))
       return I;
     DemandedMask = DemandedMask.trunc(BitWidth);
     KnownZero = KnownZero.trunc(BitWidth);
@@ -463,8 +464,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
       // Don't touch a vector-to-scalar bitcast.
       return nullptr;
 
-    if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, KnownZero,
-                             KnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 0, DemandedMask, KnownZero, KnownOne,
+                             Depth + 1))
       return I;
     assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?");
     break;
@@ -475,8 +476,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     DemandedMask = DemandedMask.trunc(SrcBitWidth);
     KnownZero = KnownZero.trunc(SrcBitWidth);
     KnownOne = KnownOne.trunc(SrcBitWidth);
-    if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, KnownZero,
-                             KnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 0, DemandedMask, KnownZero, KnownOne,
+                             Depth + 1))
       return I;
     DemandedMask = DemandedMask.zext(BitWidth);
     KnownZero = KnownZero.zext(BitWidth);
@@ -502,8 +503,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
     InputDemandedBits = InputDemandedBits.trunc(SrcBitWidth);
     KnownZero = KnownZero.trunc(SrcBitWidth);
     KnownOne = KnownOne.trunc(SrcBitWidth);
-    if (SimplifyDemandedBits(I->getOperandUse(0), InputDemandedBits, KnownZero,
-                             KnownOne, Depth + 1))
+    if (SimplifyDemandedBits(I, 0, InputDemandedBits, KnownZero, KnownOne,
+                             Depth + 1))
       return I;
     InputDemandedBits = InputDemandedBits.zext(BitWidth);
     KnownZero = KnownZero.zext(BitWidth);
@@ -534,11 +535,11 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
       // significant bit and all those below it.
       APInt DemandedFromOps(APInt::getLowBitsSet(BitWidth, BitWidth-NLZ));
       if (ShrinkDemandedConstant(I, 0, DemandedFromOps) ||
-          SimplifyDemandedBits(I->getOperandUse(0), DemandedFromOps,
-                               LHSKnownZero, LHSKnownOne, Depth + 1) ||
+          SimplifyDemandedBits(I, 0, DemandedFromOps, LHSKnownZero, LHSKnownOne,
+                               Depth + 1) ||
           ShrinkDemandedConstant(I, 1, DemandedFromOps) ||
-          SimplifyDemandedBits(I->getOperandUse(1), DemandedFromOps,
-                               LHSKnownZero, LHSKnownOne, Depth + 1)) {
+          SimplifyDemandedBits(I, 1, DemandedFromOps, LHSKnownZero, LHSKnownOne,
+                               Depth + 1)) {
         // Disable the nsw and nuw flags here: We can no longer guarantee that
         // we won't wrap after simplification. Removing the nsw/nuw flags is
         // legal here because the top bit is not demanded.
@@ -577,8 +578,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
       else if (IOp->hasNoUnsignedWrap())
         DemandedMaskIn.setHighBits(ShiftAmt);
 
-      if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn, KnownZero,
-                               KnownOne, Depth + 1))
+      if (SimplifyDemandedBits(I, 0, DemandedMaskIn, KnownZero, KnownOne,
+                               Depth + 1))
         return I;
       assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?");
       KnownZero <<= ShiftAmt;
@@ -601,8 +602,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
       if (cast<LShrOperator>(I)->isExact())
         DemandedMaskIn.setLowBits(ShiftAmt);
 
-      if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn, KnownZero,
-                               KnownOne, Depth + 1))
+      if (SimplifyDemandedBits(I, 0, DemandedMaskIn, KnownZero, KnownOne,
+                               Depth + 1))
         return I;
       assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?");
       KnownZero = APIntOps::lshr(KnownZero, ShiftAmt);
@@ -643,8 +644,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
       if (cast<AShrOperator>(I)->isExact())
         DemandedMaskIn.setLowBits(ShiftAmt);
 
-      if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn, KnownZero,
-                               KnownOne, Depth + 1))
+      if (SimplifyDemandedBits(I, 0, DemandedMaskIn, KnownZero, KnownOne,
+                               Depth + 1))
         return I;
       assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?");
       // Compute the new bits that are at the top now.
@@ -684,8 +685,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
 
         APInt LowBits = RA - 1;
         APInt Mask2 = LowBits | APInt::getSignBit(BitWidth);
-        if (SimplifyDemandedBits(I->getOperandUse(0), Mask2, LHSKnownZero,
-                                 LHSKnownOne, Depth + 1))
+        if (SimplifyDemandedBits(I, 0, Mask2, LHSKnownZero, LHSKnownOne,
+                                 Depth + 1))
           return I;
 
         // The low bits of LHS are unchanged by the srem.
@@ -720,10 +721,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
   case Instruction::URem: {
     APInt KnownZero2(BitWidth, 0), KnownOne2(BitWidth, 0);
     APInt AllOnes = APInt::getAllOnesValue(BitWidth);
-    if (SimplifyDemandedBits(I->getOperandUse(0), AllOnes, KnownZero2,
-                             KnownOne2, Depth + 1) ||
-        SimplifyDemandedBits(I->getOperandUse(1), AllOnes, KnownZero2,
-                             KnownOne2, Depth + 1))
+    if (SimplifyDemandedBits(I, 0, AllOnes, KnownZero2, KnownOne2, Depth + 1) ||
+        SimplifyDemandedBits(I, 1, AllOnes, KnownZero2, KnownOne2, Depth + 1))
       return I;
 
     unsigned Leaders = KnownZero2.countLeadingOnes();