<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="">Hi <span style="font-family: sans-serif; white-space: pre-wrap;" class="">Siddharth,</span></div><div class=""><span style="font-family: sans-serif; white-space: pre-wrap;" class=""><br class=""></span></div><div class=""><font face="sans-serif" class=""><span style="white-space: pre-wrap;" class="">I haven’t read through your code or example, so my reply may be off but I would say this is expected.</span></font></div><div class=""><font face="sans-serif" class=""><span style="white-space: pre-wrap;" class="">When you call replaceUsesOfWith, you have to make sure the values are “compatible” before doing this.</span></font></div><div class=""><font face="sans-serif" class=""><span style="white-space: pre-wrap;" class="">If the address space of both values are different and that’s not okay, then you will create wrong code.</span></font></div><div class=""><font face="sans-serif" class=""><span style="white-space: pre-wrap;" class=""><br class=""></span></font></div><div class=""><font face="sans-serif" class=""><span style="white-space: pre-wrap;" class="">Cheers,</span></font></div><div class=""><font face="sans-serif" class=""><span style="white-space: pre-wrap;" class="">-Quentin</span></font></div><br class=""><div><blockquote type="cite" class=""><div class="">On Oct 13, 2017, at 5:17 PM, Siddharth Bhat via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Hello,<div class=""><br class=""></div><div class="">Calling `replaceUsesOfWith` with a value in a different addrspace does not keep the addrspace of a GEP consistent. <span style="white-space:pre-wrap" class="">Is this known? Is this a bug or expected behaviour?</span></div><div class=""><br class=""></div><div class=""><a href="https://gist.github.com/bollu/152ba5e1c20c03c7fc6d8c7b23ba828f" class="">Minimal counterexample link</a></div><div class=""><br class=""></div><div class="">Reproduced here:</div><div class=""><br class=""></div><div class=""><pre style="word-wrap:break-word;white-space:pre-wrap" class="">#include <iostream>
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Bitcode/BitcodeWriter.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/FileSystem.h"
using namespace llvm;
using namespace std;
static const bool NON_VAR_ARG = false;
static AssertingVH<Function> getOrCreateFunction(Module &m, FunctionType *FTy,
std::string name) {
Function *F = m.getFunction(name);
if (F) return F;
return Function::Create(FTy, GlobalValue::ExternalLinkage, name, &m);
};
static const bool SHOW_ERROR = false;
int main() {
static LLVMContext ctx;
static IRBuilder<> Builder(ctx);
Module *m = new Module("Module", ctx);
Function *F = getOrCreateFunction(
*m,
FunctionType::get(Builder.getInt64Ty(),
{PointerType::get(Builder.getInt32Ty(), 42),
PointerType::get(Builder.getInt32Ty(), 1)},
NON_VAR_ARG),
"f");
auto It = F->arg_begin();
Value *Arg = &*It;
It++;
Value *Arg2 = &*It;
BasicBlock *Entry = BasicBlock::Create(ctx, "entry", F);
Builder.SetInsertPoint(Entry);
Instruction *Slot = nullptr;
<b class=""> if (SHOW_ERROR) {
Slot = cast<Instruction>(Builder.CreateGEP(Arg, {Builder.getInt64(1)}, "slot"));
errs() << "Slot(original): " << *Slot << "\n";
Slot->replaceUsesOfWith(Arg, Arg2);
errs() << "Slot(replaced): " << *Slot << "\n";
}
else {
Slot = cast<Instruction>(Builder.CreateGEP(Arg2, {Builder.getInt64(1)}, "slot"));
}
</b> Value *TypedSlot = Builder.CreateBitCast(Slot, PointerType::get(Builder.getInt64Ty(), 1), "slot_typed");
Value *Load = Builder.CreateLoad(TypedSlot, "Val");
Builder.CreateRet(Load);
if (verifyModule(*m) == 1) {
errs() << "module has an error: ";
verifyModule(*m, &errs());
report_fatal_error("buggy module.");
}
outs() << *m << "\n";
// llvm::WriteBitcodeToFile(m, outs());
return 1;
};</pre><pre style="word-wrap:break-word;white-space:pre-wrap" class=""><br class=""></pre><pre style="word-wrap:break-word;white-space:pre-wrap" class=""><br class=""></pre><pre style="word-wrap:break-word;white-space:pre-wrap" class="">Output:</pre><pre style="word-wrap:break-word;white-space:pre-wrap" class="">### `SHOW_ERROR = 0`
```ll
; ModuleID = 'Module'
source_filename = "Module"
define i64 @f(i32 addrspace(42)*, i32 addrspace(1)*) {
entry:
%slot = getelementptr i32, i32 addrspace(1)* %1, i64 1
%slot_typed = bitcast i32 addrspace(1)* %slot to i64 addrspace(1)*
%Val = load i64, i64 addrspace(1)* %slot_typed
ret i64 %Val
}
```
### `SHOW_ERROR = 1`
```
Slot(original): %slot = getelementptr i32, i32 addrspace(42)* %0, i64 1
Slot(replaced): %slot = getelementptr i32, i32 addrspace(1)* %1, i64 1
<b class="">Assertion failed: (castIsValid(op, S, Ty) && "Invalid cast!"), function Create, file /Users/bollu/work/LLVM-all/polly/llvm/lib/IR/Instructions.cpp, line 2592.
</b>[5] 56333 abort ./prog
```</pre><pre style="word-wrap:break-word;white-space:pre-wrap" class=""><br class=""></pre><pre style="word-wrap:break-word;white-space:pre-wrap" class=""><font face="sans-serif" class="">Thanks,</font></pre><pre style="word-wrap:break-word;white-space:pre-wrap" class=""><font face="sans-serif" class="">~Siddharth.</font></pre></div></div><div dir="ltr" class="">-- <br class=""></div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr" class="">Sending this from my phone, please excuse any typos!</div></div>
_______________________________________________<br class="">LLVM Developers mailing list<br class=""><a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a><br class="">http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev<br class=""></div></blockquote></div><br class=""></body></html>