| Issue |
132563
|
| Summary |
[VectorCombine] Crash occured while fold load-insertelement-store
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
ParkHanbum
|
This is an IR sample that crashes.
```
define void @src_1_idx(ptr %q, i8 zeroext %s, i1 %idx) {
entry:
%0 = load <16 x i8>, ptr %q
%v1 = insertelement <16 x i8> %0, i8 %s, i1 %idx
store <16 x i8> %v1, ptr %q
ret void
}
define void @src_2_idx(ptr %q, i8 zeroext %s, i8 %idx) {
entry:
%0 = load <256 x i8>, ptr %q
%v1 = insertelement <256 x i8> %0, i8 %s, i8 %idx
store <256 x i8> %v1, ptr %q
ret void
}
```
and this is debugging message with crash dump
```
VECTORCOMBINE on src_2_idx
VC: Visiting: %0 = load <16 x i8>, ptr %q, align 16
VC: Visiting: %v1 = insertelement <16 x i8> %0, i8 %s, i1 %idx
VC: Visiting: store <16 x i8> %v1, ptr %q, align 16
Assertion failed: (llvm::isUIntN(BitWidth, val) && "Value is not an N-bit unsigned value"), function APInt, file APInt.h, line 128.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0. Program arguments: bin/opt -passes=vector-combine t1.ll -S -debug
1. Running pass "function(vector-combine)" on module "t1.ll"
2. Running pass "vector-combine" on function "src_2_idx"
#0 0x00000001026ca6ac llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Users/b2sy/work/test3/bin/opt+0x1019566ac)
#1 0x00000001026c8770 llvm::sys::RunSignalHandlers() (/Users/b2sy/work/test3/bin/opt+0x101954770)
#2 0x00000001026cae7c SignalHandler(int, __siginfo*, void*) (/Users/b2sy/work/test3/bin/opt+0x101956e7c)
#3 0x000000019733ede4 (/usr/lib/system/libsystem_platform.dylib+0x180482de4)
#4 0x0000000197307f70 (/usr/lib/system/libsystem_pthread.dylib+0x18044bf70)
#5 0x0000000197214908 (/usr/lib/system/libsystem_c.dylib+0x180358908)
#6 0x0000000197213c1c (/usr/lib/system/libsystem_c.dylib+0x180357c1c)
#7 0x00000001032ad794 isUpperSubvectorUndef(llvm::SDValue, llvm::SDLoc const&, llvm::SelectionDAG&) (.cold.2) (/Users/b2sy/work/test3/bin/opt+0x102539794)
#8 0x00000001029c4990 canScalarizeAccess(llvm::VectorType*, llvm::Value*, llvm::Instruction*, llvm::AssumptionCache&, llvm::DominatorTree const&) (/Users/b2sy/work/test3/bin/opt+0x101c50990)
```
problem occured here
```
// VectorCombine.cpp:1447
unsigned IntWidth = Idx->getType()->getScalarSizeInBits();
APInt Zero(IntWidth, 0);
APInt MaxElts(IntWidth, NumElements); <<< crash
ConstantRange ValidIndices(Zero, MaxElts);
ConstantRange IdxRange(IntWidth, true);
```
I think this code is necessary because it checks to see if the index specified by insertelement is in an accessible range on the vector, so I think we need to add exception handling to fix the problem.
What do you think?
Note that this is not a real-world issue, but a bug that I discovered while writing the patch and creating the verification code.
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