[ConstantFold] Support ptrtoaddr in global alignment fold

Treat it the same way as ptrtoint.

Author: nikic

llvm/lib/IR/ConstantFold.cpp

@@ -741,7 +741,8 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
       assert(!CI2->isZero() && "And zero handled above");
       if (ConstantExpr *CE1 = dyn_cast<ConstantExpr>(C1)) {
         // If and'ing the address of a global with a constant, fold it.
-        if (CE1->getOpcode() == Instruction::PtrToInt &&
+        if ((CE1->getOpcode() == Instruction::PtrToInt ||
+             CE1->getOpcode() == Instruction::PtrToAddr) &&
             isa<GlobalValue>(CE1->getOperand(0))) {
           GlobalValue *GV = cast<GlobalValue>(CE1->getOperand(0));
 

llvm/unittests/IR/ConstantsTest.cpp

@@ -564,13 +564,17 @@ TEST(ConstantsTest, FoldGlobalVariablePtr) {
 
   Global->setAlignment(Align(4));
 
-  ConstantInt *TheConstant(ConstantInt::get(IntType, 2));
+  ConstantInt *TheConstant = ConstantInt::get(IntType, 2);
 
-  Constant *TheConstantExpr(ConstantExpr::getPtrToInt(Global.get(), IntType));
+  Constant *PtrToInt = ConstantExpr::getPtrToInt(Global.get(), IntType);
+  ASSERT_TRUE(
+      ConstantFoldBinaryInstruction(Instruction::And, PtrToInt, TheConstant)
+          ->isNullValue());
 
-  ASSERT_TRUE(ConstantFoldBinaryInstruction(Instruction::And, TheConstantExpr,
-                                            TheConstant)
-                  ->isNullValue());
+  Constant *PtrToAddr = ConstantExpr::getPtrToAddr(Global.get(), IntType);
+  ASSERT_TRUE(
+      ConstantFoldBinaryInstruction(Instruction::And, PtrToAddr, TheConstant)
+          ->isNullValue());
 }
 
 // Check that containsUndefOrPoisonElement and containsPoisonElement is working