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[InstCombine] fix crash due to ignored addrspacecast 

Summary:
Part of the InstCombine code for simplifying GEPs looks through
addrspacecasts. However, this was done by updating a variable
also used by the next transformation, for marking GEPs as
inbounds. This led to replacing a GEP with a similar instruction
in a different addrspace, which caused an assertion failure in RAUW.

This caused julia issue https://github.com/JuliaLang/julia/issues/27055

Patch by Jeff Bezanson <jeff@juliacomputing.com>

Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D46722

llvm-svn: 332302
This commit is contained in:
Keno Fischer 2018-05-14 22:05:01 +00:00
parent 165587b424
commit de577af8c0
2 changed files with 22 additions and 2 deletions
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5
llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
View File

@ -1937,16 +1937,17 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// addrspacecast between types is canonicalized as a bitcast, then an // addrspacecast between types is canonicalized as a bitcast, then an
// addrspacecast. To take advantage of the below bitcast + struct GEP, look // addrspacecast. To take advantage of the below bitcast + struct GEP, look
// through the addrspacecast. // through the addrspacecast.
Value *ASCStrippedPtrOp = PtrOp;
if (auto *ASC = dyn_cast<AddrSpaceCastInst>(PtrOp)) { if (auto *ASC = dyn_cast<AddrSpaceCastInst>(PtrOp)) {
// X = bitcast A addrspace(1)* to B addrspace(1)* // X = bitcast A addrspace(1)* to B addrspace(1)*
// Y = addrspacecast A addrspace(1)* to B addrspace(2)* // Y = addrspacecast A addrspace(1)* to B addrspace(2)*
// Z = gep Y, <...constant indices...> // Z = gep Y, <...constant indices...>
// Into an addrspacecasted GEP of the struct. // Into an addrspacecasted GEP of the struct.
if (auto *BC = dyn_cast<BitCastInst>(ASC->getOperand(0))) if (auto *BC = dyn_cast<BitCastInst>(ASC->getOperand(0)))
PtrOp = BC; ASCStrippedPtrOp = BC;
} }
if (auto *BCI = dyn_cast<BitCastInst>(PtrOp)) { if (auto *BCI = dyn_cast<BitCastInst>(ASCStrippedPtrOp)) {
Value *SrcOp = BCI->getOperand(0); Value *SrcOp = BCI->getOperand(0);
PointerType *SrcType = cast<PointerType>(BCI->getSrcTy()); PointerType *SrcType = cast<PointerType>(BCI->getSrcTy());
Type *SrcEltType = SrcType->getElementType(); Type *SrcEltType = SrcType->getElementType();

19
llvm/test/Transforms/InstCombine/gep-addrspace.ll
View File

@ -32,3 +32,22 @@ entry:
ret void ret void
} }
declare void @escape_alloca(i16*)
; check that addrspacecast is not ignored (leading to an assertion failure)
; when trying to mark a GEP as inbounds
define { i8, i8 } @inbounds_after_addrspacecast() {
top:
; CHECK-LABEL: @inbounds_after_addrspacecast
%0 = alloca i16, align 2
call void @escape_alloca(i16* %0)
%tmpcast = bitcast i16* %0 to [2 x i8]*
; CHECK: addrspacecast [2 x i8]* %tmpcast to [2 x i8] addrspace(11)*
%1 = addrspacecast [2 x i8]* %tmpcast to [2 x i8] addrspace(11)*
; CHECK: getelementptr [2 x i8], [2 x i8] addrspace(11)* %1, i64 0, i64 1
%2 = getelementptr [2 x i8], [2 x i8] addrspace(11)* %1, i64 0, i64 1
; CHECK: addrspace(11)
%3 = load i8, i8 addrspace(11)* %2, align 1
%.fca.1.insert = insertvalue { i8, i8 } zeroinitializer, i8 %3, 1
ret { i8, i8 } %.fca.1.insert
}