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Do not promote null values because it may be unsafe to do so.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42270 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2007-09-24 20:02:42 +00:00
parent d81ccc2806
commit 128459b85b
2 changed files with 50 additions and 0 deletions
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4
lib/Transforms/Scalar/LICM.cpp
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@ -800,6 +800,10 @@ void LICM::FindPromotableValuesInLoop(
break;
}
// Do not promote null values because it may be unsafe to do so.
if (isa<ConstantPointerNull>(V))
PointerOk = false;
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) {
// If GEP base is NULL then the calculated address used by Store or
// Load instruction is invalid. Do not promote this value because

46
test/Transforms/LICM/2007-09-24-PromoteNullValue.ll Normal file
View File

@ -0,0 +1,46 @@
; Do not promote null value because it may be unsafe to do so.
; RUN: llvm-as < %s | opt -licm | llvm-dis | not grep promoted
define i32 @f(i32 %foo, i32 %bar, i32 %com) {
entry:
%tmp2 = icmp eq i32 %foo, 0 ; <i1> [#uses=1]
br i1 %tmp2, label %cond_next, label %cond_true
cond_true: ; preds = %entry
br label %return
cond_next: ; preds = %entry
br label %bb
bb: ; preds = %bb15, %cond_next
switch i32 %bar, label %bb15 [
i32 1, label %bb6
]
bb6: ; preds = %bb
%tmp8 = icmp eq i32 %com, 0 ; <i1> [#uses=1]
br i1 %tmp8, label %cond_next14, label %cond_true11
cond_true11: ; preds = %bb6
br label %return
cond_next14: ; preds = %bb6
store i8 0, i8* null
br label %bb15
bb15: ; preds = %cond_next14, %bb
br label %bb
return: ; preds = %cond_true11, %cond_true
%storemerge = phi i32 [ 0, %cond_true ], [ undef, %cond_true11 ] ; <i32> [#uses=1]
ret i32 %storemerge
}
define i32 @kdMain() {
entry:
%tmp1 = call i32 @f( i32 0, i32 1, i32 1 ) ; <i32> [#uses=0]
call void @exit( i32 0 )
unreachable
}
declare void @exit(i32)