[InstCombine] Support vector splats in foldSelectICmpAnd.

Unfortunately, it looks like there's some other missed optimizations in the generated code for some of these cases. I'll try to look at some of those next.

llvm-svn: 310184

1 files changed, 23 insertions, 15 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index b5b8aa33267..92f3c1d9d89 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -597,18 +597,24 @@ canonicalizeMinMaxWithConstant(SelectInst &Sel, ICmpInst &Cmp,
 /// icmp instruction with zero, and we have an 'and' with the non-constant value
 /// and a power of two we can turn the select into a shift on the result of the
 /// 'and'.
-static Value *foldSelectICmpAnd(const SelectInst &SI, const ICmpInst *IC,
+static Value *foldSelectICmpAnd(Type *SelType, const ICmpInst *IC,
                                 APInt TrueVal, APInt FalseVal,
                                 InstCombiner::BuilderTy &Builder) {
-  if (!IC->isEquality() || !SI.getType()->isIntegerTy())
+  assert(SelType->isIntOrIntVectorTy() && "Not an integer select?");
+
+  // If this is a vector select, we need a vector compare.
+  if (SelType->isVectorTy() != IC->getType()->isVectorTy())
+    return nullptr;
+
+  if (!IC->isEquality())
     return nullptr;
 
   if (!match(IC->getOperand(1), m_Zero()))
     return nullptr;
 
-  ConstantInt *AndRHS;
+  const APInt *AndRHS;
   Value *LHS = IC->getOperand(0);
-  if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
+  if (!match(LHS, m_And(m_Value(), m_Power2(AndRHS))))
     return nullptr;
 
   // If both select arms are non-zero see if we have a select of the form
@@ -628,28 +634,27 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, const ICmpInst *IC,
     FalseVal -= Offset;
   }
 
-  // Make sure the mask in the 'and' and one of the select arms is a power of 2.
-  if (!AndRHS->getValue().isPowerOf2() ||
-      (!TrueVal.isPowerOf2() && !FalseVal.isPowerOf2()))
+  // Make sure one of the select arms is a power of 2.
+  if (!TrueVal.isPowerOf2() && !FalseVal.isPowerOf2())
     return nullptr;
 
   // Determine which shift is needed to transform result of the 'and' into the
   // desired result.
   const APInt &ValC = !TrueVal.isNullValue() ? TrueVal : FalseVal;
   unsigned ValZeros = ValC.logBase2();
-  unsigned AndZeros = AndRHS->getValue().logBase2();
+  unsigned AndZeros = AndRHS->logBase2();
 
   // If types don't match we can still convert the select by introducing a zext
   // or a trunc of the 'and'.
   Value *V = LHS;
   if (ValZeros > AndZeros) {
-    V = Builder.CreateZExtOrTrunc(V, SI.getType());
+    V = Builder.CreateZExtOrTrunc(V, SelType);
     V = Builder.CreateShl(V, ValZeros - AndZeros);
   } else if (ValZeros < AndZeros) {
     V = Builder.CreateLShr(V, AndZeros - ValZeros);
-    V = Builder.CreateZExtOrTrunc(V, SI.getType());
+    V = Builder.CreateZExtOrTrunc(V, SelType);
   } else
-    V = Builder.CreateZExtOrTrunc(V, SI.getType());
+    V = Builder.CreateZExtOrTrunc(V, SelType);
 
   // Okay, now we know that everything is set up, we just don't know whether we
   // have a icmp_ne or icmp_eq and whether the true or false val is the zero.
@@ -670,11 +675,14 @@ Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
   Value *TrueVal = SI.getTrueValue();
   Value *FalseVal = SI.getFalseValue();
 
-  if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal))
-    if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal))
-      if (Value *V = foldSelectICmpAnd(SI, ICI, TrueValC->getValue(),
-                                       FalseValC->getValue(), Builder))
+  {
+    const APInt *TrueValC, *FalseValC;
+    if (match(TrueVal, m_APInt(TrueValC)) &&
+        match(FalseVal, m_APInt(FalseValC)))
+      if (Value *V = foldSelectICmpAnd(SI.getType(), ICI, *TrueValC,
+                                       *FalseValC, Builder))
         return replaceInstUsesWith(SI, V);
+  }
 
   if (Instruction *NewSel = canonicalizeMinMaxWithConstant(SI, *ICI, Builder))
     return NewSel;