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Add missing check for presence of target data. 

This avoids a crash in visitAllocaInst when target data isn't available.

llvm-svn: 164539
This commit is contained in:
Richard Osborne 2012-09-24 17:10:03 +00:00
parent 8493cad160
commit 2fd29bfb90
2 changed files with 41 additions and 20 deletions
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42
llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
View File

@ -264,26 +264,28 @@ Instruction *InstCombiner::visitAllocaInst(AllocaInst &AI) {
}
}
// Check to see if this allocation is only modified by a memcpy/memmove from
// a constant global whose alignment is equal to or exceeds that of the
// allocation. If this is the case, we can change all users to use
// the constant global instead. This is commonly produced by the CFE by
// constructs like "void foo() { int A[] = {1,2,3,4,5,6,7,8,9...}; }" if 'A'
// is only subsequently read.
SmallVector<Instruction *, 4> ToDelete;
if (MemTransferInst *Copy = isOnlyCopiedFromConstantGlobal(&AI, ToDelete)) {
if (AI.getAlignment() <= getPointeeAlignment(Copy->getSource(), *TD)) {
DEBUG(dbgs() << "Found alloca equal to global: " << AI << '\n');
DEBUG(dbgs() << " memcpy = " << *Copy << '\n');
for (unsigned i = 0, e = ToDelete.size(); i != e; ++i)
EraseInstFromFunction(*ToDelete[i]);
Constant *TheSrc = cast<Constant>(Copy->getSource());
Instruction *NewI
= ReplaceInstUsesWith(AI, ConstantExpr::getBitCast(TheSrc,
AI.getType()));
EraseInstFromFunction(*Copy);
++NumGlobalCopies;
return NewI;
if (TD) {
// Check to see if this allocation is only modified by a memcpy/memmove from
// a constant global whose alignment is equal to or exceeds that of the
// allocation. If this is the case, we can change all users to use
// the constant global instead. This is commonly produced by the CFE by
// constructs like "void foo() { int A[] = {1,2,3,4,5,6,7,8,9...}; }" if 'A'
// is only subsequently read.
SmallVector<Instruction *, 4> ToDelete;
if (MemTransferInst *Copy = isOnlyCopiedFromConstantGlobal(&AI, ToDelete)) {
if (AI.getAlignment() <= getPointeeAlignment(Copy->getSource(), *TD)) {
DEBUG(dbgs() << "Found alloca equal to global: " << AI << '\n');
DEBUG(dbgs() << " memcpy = " << *Copy << '\n');
for (unsigned i = 0, e = ToDelete.size(); i != e; ++i)
EraseInstFromFunction(*ToDelete[i]);
Constant *TheSrc = cast<Constant>(Copy->getSource());
Instruction *NewI
= ReplaceInstUsesWith(AI, ConstantExpr::getBitCast(TheSrc,
AI.getType()));
EraseInstFromFunction(*Copy);
++NumGlobalCopies;
return NewI;
}
}
}

19
llvm/test/Transforms/InstCombine/2012-09-24-MemcpyFromGlobalCrash.ll Normal file
View File

@ -0,0 +1,19 @@
; RUN: opt < %s -instcombine -S | FileCheck %s
; Check we don't crash due to lack of target data.
@G = constant [100 x i8] zeroinitializer
declare void @bar(i8*)
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, i1) nounwind
define void @test() {
; CHECK: @test
; CHECK: llvm.memcpy
; CHECK ret void
%A = alloca [100 x i8]
%a = getelementptr inbounds [100 x i8]* %A, i64 0, i64 0
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %a, i8* getelementptr inbounds ([100 x i8]* @G, i64 0, i32 0), i64 100, i32 4, i1 false)
call void @bar(i8* %a) readonly
ret void
}