Revert "Add support for combining GEPs across PHI nodes"

[oota-llvm.git] / lib / Transforms / InstCombine / InstCombineSelect.cpp

diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 50b5b3740f116f63664e13254172743ee726a4f9..9a41e4b9406ad5a6563a2f16d7e9f314bc87ec2a 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -365,15 +365,7 @@ static Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
 /// 1. The icmp predicate is inverted
 /// 2. The select operands are reversed
 /// 3. The magnitude of C2 and C1 are flipped
-///
-/// This also tries to turn
-/// --- Single bit tests:
-/// if ((x & C) == 0) x |= C   to  x |= C
-/// if ((x & C) != 0) x ^= C   to  x &= ~C
-/// if ((x & C) == 0) x ^= C   to  x |= C
-/// if ((x & C) != 0) x &= ~C  to  x &= ~C
-/// if ((x & C) == 0) x &= ~C  to  nothing
-static Value *foldSelectICmpAndOr(SelectInst &SI, Value *TrueVal,
+static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal,
                                   Value *FalseVal,
                                   InstCombiner::BuilderTy *Builder) {
   const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
@@ -392,34 +384,10 @@ static Value *foldSelectICmpAndOr(SelectInst &SI, Value *TrueVal,
     return nullptr;
 
   const APInt *C2;
-
-  // if ((x & C) != 0) x ^= C becomes x &= ~C
-  if (match(FalseVal, m_Xor(m_Specific(TrueVal), m_APInt(C2))) && C1 == C2) {
-    return Builder->CreateAnd(TrueVal, ~(*C1));
-  }
-
-  // if ((x & C) == 0) x ^= C becomes x |= C
-  if (match(TrueVal, m_Xor(m_Specific(FalseVal), m_APInt(C2))) && C1 == C2) {
-    return Builder->CreateOr(FalseVal, *C1);
-  }
-
-  // if ((x & C) != 0) x &= ~C becomes x &= ~C
-  // if ((x & C) == 0) x &= ~C becomes nothing
-  if ((match(FalseVal, m_And(m_Specific(TrueVal), m_APInt(C2))) ||
-       match(TrueVal, m_And(m_Specific(FalseVal), m_APInt(C2)))) &&
-      *C1 == ~(*C2)) {
-    return FalseVal;
-  }
-
-  bool OrOnFalseVal = false;
-  bool OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
-
-  // if ((x & C) == 0) x |= C becomes x |= C
-  if (OrOnTrueVal && C1 == C2)
-    return TrueVal;
-
-  if (!OrOnTrueVal)
-    OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
+  bool OrOnTrueVal = false;
+  bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
+  if (!OrOnFalseVal)
+    OrOnTrueVal = match(TrueVal, m_Or(m_Specific(FalseVal), m_Power2(C2)));
 
   if (!OrOnFalseVal && !OrOnTrueVal)
     return nullptr;
@@ -683,11 +651,35 @@ Instruction *InstCombiner::FoldSPFofSPF(Instruction *Inner,
       return ReplaceInstUsesWith(Outer, C);
   }
 
-  // TODO: MIN(MIN(A, 23), 97)
+  if (SPF1 == SPF2) {
+    if (ConstantInt *CB = dyn_cast<ConstantInt>(B)) {
+      if (ConstantInt *CC = dyn_cast<ConstantInt>(C)) {
+        APInt ACB = CB->getValue();
+        APInt ACC = CC->getValue();
+
+        // MIN(MIN(A, 23), 97) -> MIN(A, 23)
+        // MAX(MAX(A, 97), 23) -> MAX(A, 97)
+        if ((SPF1 == SPF_UMIN && ACB.ule(ACC)) ||
+            (SPF1 == SPF_SMIN && ACB.sle(ACC)) ||
+            (SPF1 == SPF_UMAX && ACB.uge(ACC)) ||
+            (SPF1 == SPF_SMAX && ACB.sge(ACC)))
+          return ReplaceInstUsesWith(Outer, Inner);
+
+        // MIN(MIN(A, 97), 23) -> MIN(A, 23)
+        // MAX(MAX(A, 23), 97) -> MAX(A, 97)
+        if ((SPF1 == SPF_UMIN && ACB.ugt(ACC)) ||
+            (SPF1 == SPF_SMIN && ACB.sgt(ACC)) ||
+            (SPF1 == SPF_UMAX && ACB.ult(ACC)) ||
+            (SPF1 == SPF_SMAX && ACB.slt(ACC))) {
+          Outer.replaceUsesOfWith(Inner, A);
+          return &Outer;
+        }
+      }
+    }
+  }
   return nullptr;
 }
 
-
 /// foldSelectICmpAnd - If one of the constants is zero (we know they can't
 /// both be) and we have an icmp instruction with zero, and we have an 'and'
 /// with the non-constant value and a power of two we can turn the select