[IR] Remove support for lshr/ashr constant expressions (#71955)

Remove support for the lshr and ashr constant expressions. All places
creating them have been removed beforehand, so this just removes the
APIs and uses of these constant expressions in tests.

This is part of
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179.

1 files changed, 0 insertions, 23 deletions

diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp
index 0358f99..25f7ac2 100644
--- a/llvm/lib/IR/ConstantFold.cpp
+++ b/llvm/lib/IR/ConstantFold.cpp
@@ -155,29 +155,6 @@ static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
 
   switch (CE->getOpcode()) {
   default: return nullptr;
-  case Instruction::LShr: {
-    ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
-    if (!Amt)
-      return nullptr;
-    APInt ShAmt = Amt->getValue();
-    // Cannot analyze non-byte shifts.
-    if ((ShAmt & 7) != 0)
-      return nullptr;
-    ShAmt.lshrInPlace(3);
-
-    // If the extract is known to be all zeros, return zero.
-    if (ShAmt.uge(CSize - ByteStart))
-      return Constant::getNullValue(
-          IntegerType::get(CE->getContext(), ByteSize * 8));
-    // If the extract is known to be fully in the input, extract it.
-    if (ShAmt.ule(CSize - (ByteStart + ByteSize)))
-      return ExtractConstantBytes(CE->getOperand(0),
-                                  ByteStart + ShAmt.getZExtValue(), ByteSize);
-
-    // TODO: Handle the 'partially zero' case.
-    return nullptr;
-  }
-
   case Instruction::Shl: {
     ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
     if (!Amt)