[GlobalOpt] Fix the assert for stored once non-pointer to global address

[scui]

Summary

This is to fix the assert @bjope reported due to the code change of https://reviews.llvm.org/D106589. The test case from @bjope is also included.

[efriedma]

LGTM

[bjope]

I don't know much about globalopt and the actual code change. But the test case looks good, and I've verified that this fix also works for my original test case (the non-reduced C code).

llvm/lib/Transforms/IPO/GlobalOpt.cpp

optimizeOnceStoredGlobal(GlobalVariable *GV, Value *StoredOnceVal,
   StoredOnceVal = StoredOnceVal->stripPointerCasts();
 
   // If we are dealing with a pointer global that is initialized to null and
   // only has one (non-null) value stored into it, then we can optimize any
   // users of the loaded value (often calls and loads) that would trap if the
   // value was null.
   if (GV->getInitializer()->getType()->isPointerTy() &&
       GV->getInitializer()->isNullValue() &&
+      StoredOnceVal->getType()->isPointerTy() &&
       !NullPointerIsDefined(
           nullptr /* F */,
           GV->getInitializer()->getType()->getPointerAddressSpace())) {
     if (Constant *SOVC = dyn_cast<Constant>(StoredOnceVal)) {
       if (GV->getInitializer()->getType() != SOVC->getType())
         SOVC = ConstantExpr::getBitCast(SOVC, GV->getInitializer()->getType());
 
       // Optimize away any trapping uses of the loaded value.

llvm/test/Transforms/GlobalOpt/2021-08-02-CastStoreOnceP2I.ll

+; RUN: opt -globalopt -S < %s | FileCheck %s
+; RUN: opt -passes=globalopt -S < %s | FileCheck %s
+
+; This tests the assignemnt of non-pointer to global address
+; (assert due to D106589).
+
+@a162 = internal global i16* null, align 1
+
+define void @f363() {
+; CHECK-LABEL: @f363(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = load i16*, i16** @a162, align 1
+; CHECK-NEXT:    store i16 0, i16* bitcast (i16** @a162 to i16*), align 1
+; CHECK-NEXT:    ret void
+;
+entry:
+  %0 = load i16*, i16** @a162, align 1
+  store i16 0, i16* bitcast (i16** @a162 to i16*), align 1
+  ret void
+}