Revert "[InstCombine] allow splat vector folds in adjustMinMax()"

This reverts commit r285732.

This change introduced a new assertion failure in the following
testcase at -O2:

typedef short __v8hi __attribute__((__vector_size__(16)));
__v8hi foo(__v8hi &V1, __v8hi &V2, unsigned mask) {
  __v8hi Result = V1;
  if (mask & 0x80)
    Result[0] = V2[0];
  return Result;
}

llvm-svn: 285866

1 files changed, 14 insertions, 10 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 03fc1a09edc..cfae47fbd7e 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -424,20 +424,24 @@ static bool adjustMinMax(SelectInst &Sel, ICmpInst &Cmp) {
   Value *FalseVal = Sel.getFalseValue();
 
   // We may move or edit the compare, so make sure the select is the only user.
-  const APInt *CmpC;
-  if (!Cmp.hasOneUse() || !match(CmpRHS, m_APInt(CmpC)))
+  if (!Cmp.hasOneUse())
     return false;
 
-  // These transforms only work for selects of integers or vector integers.
-  auto *SelEltTy = dyn_cast<IntegerType>(Sel.getType()->getScalarType());
-  if (!SelEltTy)
+  // FIXME: Use m_APInt to allow vector folds.
+  auto *CI = dyn_cast<ConstantInt>(CmpRHS);
+  if (!CI)
+    return false;
+
+  // These transformations only work for selects over integers.
+  IntegerType *SelectTy = dyn_cast<IntegerType>(Sel.getType());
+  if (!SelectTy)
     return false;
 
   Constant *AdjustedRHS;
   if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT)
-    AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC + 1);
+    AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() + 1);
   else if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT)
-    AdjustedRHS = ConstantInt::get(CmpRHS->getType(), *CmpC - 1);
+    AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() - 1);
   else
     return false;
 
@@ -450,8 +454,8 @@ static bool adjustMinMax(SelectInst &Sel, ICmpInst &Cmp) {
   // Types do not match. Instead of calculating this with mixed types, promote
   // all to the larger type. This enables scalar evolution to analyze this
   // expression.
-  else if (CmpRHS->getType()->getScalarSizeInBits() < SelEltTy->getBitWidth()) {
-    Constant *SextRHS = ConstantExpr::getSExt(AdjustedRHS, Sel.getType());
+  else if (CmpRHS->getType()->getScalarSizeInBits() < SelectTy->getBitWidth()) {
+    Constant *SextRHS = ConstantExpr::getSExt(AdjustedRHS, SelectTy);
 
     // X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X
     // X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X
@@ -465,7 +469,7 @@ static bool adjustMinMax(SelectInst &Sel, ICmpInst &Cmp) {
       CmpLHS = FalseVal;
       AdjustedRHS = SextRHS;
     } else if (Cmp.isUnsigned()) {
-      Constant *ZextRHS = ConstantExpr::getZExt(AdjustedRHS, Sel.getType());
+      Constant *ZextRHS = ConstantExpr::getZExt(AdjustedRHS, SelectTy);
       // X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X
       // X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X
       // zext + signed compare cannot be changed: