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if jump threading is able to infer interesting values on both 

the LHS and RHS of an and/or instruction, don't multiply add
known predecessor values.  This fixes the crash on testcase
from PR7498

llvm-svn: 108114
This commit is contained in:
Chris Lattner 2010-07-12 00:47:34 +00:00
parent fd4a09fc0a
commit bbc25ff5cc
2 changed files with 37 additions and 2 deletions
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15
llvm/lib/Transforms/Scalar/JumpThreading.cpp
View File

@ -346,8 +346,19 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){
}
for (unsigned i = 0, e = RHSVals.size(); i != e; ++i)
if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0) {
Result.push_back(RHSVals[i]);
Result.back().first = InterestingVal;
// If we already inferred a value for this block on the LHS, don't
// re-add it.
bool HasValue = false;
for (unsigned r = 0, e = Result.size(); r != e; ++r)
if (Result[r].second == RHSVals[i].second) {
HasValue = true;
break;
}
if (!HasValue) {
Result.push_back(RHSVals[i]);
Result.back().first = InterestingVal;
}
}
return !Result.empty();
}

24
llvm/test/Transforms/JumpThreading/crash.ll
View File

@ -363,3 +363,27 @@ F:
ret i32 1422
}
; PR7498
define void @test14() nounwind {
entry:
%cmp33 = icmp slt i8 undef, 0 ; <i1> [#uses=1]
%tobool = icmp eq i8 undef, 0 ; <i1> [#uses=1]
br i1 %tobool, label %land.end69, label %land.rhs
land.rhs: ; preds = %entry
br label %land.end69
land.end69: ; preds = %land.rhs, %entry
%0 = phi i1 [ undef, %land.rhs ], [ true, %entry ] ; <i1> [#uses=1]
%cmp71 = or i1 true, %0 ; <i1> [#uses=1]
%cmp73 = xor i1 %cmp33, %cmp71 ; <i1> [#uses=1]
br i1 %cmp73, label %if.then, label %if.end
if.then: ; preds = %land.end69
ret void
if.end: ; preds = %land.end69
ret void
}