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SCEV: Even if the latch terminator is foldable we can't deduce the result of an unrelated condition with it. 

Fixes PR14432.

llvm-svn: 168711
This commit is contained in:
Benjamin Kramer 2012-11-27 18:16:32 +00:00
parent 5b4628201f
commit e20e124280
2 changed files with 58 additions and 3 deletions
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7
llvm/lib/Analysis/ScalarEvolution.cpp
View File

@ -6149,9 +6149,10 @@ bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred,
if (SimplifyICmpOperands(Pred, LHS, RHS))
if (LHS == RHS)
return CmpInst::isTrueWhenEqual(Pred);
if (SimplifyICmpOperands(FoundPred, FoundLHS, FoundRHS))
if (FoundLHS == FoundRHS)
return CmpInst::isFalseWhenEqual(Pred);
// Canonicalize the found cond too. We can't conclude a result from the
// simplified values.
SimplifyICmpOperands(FoundPred, FoundLHS, FoundRHS);
// Check to see if we can make the LHS or RHS match.
if (LHS == FoundRHS || RHS == FoundLHS) {

54
llvm/test/Transforms/IndVarSimplify/eliminate-comparison.ll
View File

@ -106,3 +106,57 @@ loop:
return:
ret void
}
; PR14432
; Indvars should not turn the second loop into an infinite one.
; CHECK: @func_11
; CHECK: %tmp5 = icmp slt i32 %__key6.0, 10
; CHECK-NOT: br i1 true, label %noassert68, label %unrolledend
define i32 @func_11() nounwind uwtable {
entry:
br label %forcond
forcond: ; preds = %noassert, %entry
%__key6.0 = phi i32 [ 2, %entry ], [ %tmp37, %noassert ]
%tmp5 = icmp slt i32 %__key6.0, 10
br i1 %tmp5, label %noassert, label %forcond38.preheader
forcond38.preheader: ; preds = %forcond
br label %forcond38
noassert: ; preds = %forbody
%tmp13 = sdiv i32 -32768, %__key6.0
%tmp2936 = shl i32 %tmp13, 24
%sext23 = shl i32 %tmp13, 24
%tmp32 = icmp eq i32 %tmp2936, %sext23
%tmp37 = add i32 %__key6.0, 1
br i1 %tmp32, label %forcond, label %assert33
assert33: ; preds = %noassert
tail call void @llvm.trap()
unreachable
forcond38: ; preds = %noassert68, %forcond38.preheader
%__key8.0 = phi i32 [ %tmp81, %noassert68 ], [ 2, %forcond38.preheader ]
%tmp46 = icmp slt i32 %__key8.0, 10
br i1 %tmp46, label %noassert68, label %unrolledend
noassert68: ; preds = %forbody39
%tmp57 = sdiv i32 -32768, %__key8.0
%sext34 = shl i32 %tmp57, 16
%sext21 = shl i32 %tmp57, 16
%tmp76 = icmp eq i32 %sext34, %sext21
%tmp81 = add i32 %__key8.0, 1
br i1 %tmp76, label %forcond38, label %assert77
assert77: ; preds = %noassert68
tail call void @llvm.trap()
unreachable
unrolledend: ; preds = %forcond38
ret i32 0
}
declare void @llvm.trap() noreturn nounwind