[llvm-commits] [llvm] r168711 - in /llvm/trunk: lib/Analysis/ScalarEvolution.cpp test/Transforms/IndVarSimplify/eliminate-comparison.ll

[Benjamin Kramer]

On 29.11.2012, at 16:55, Pawel Wodnicki <pawel at 32bitmicro.com> wrote:

> Ben,
> 
> Have you heard from Chris about r168711 approval?

Not yet.

- Ben

> 
>> 
>> On 27.11.2012, at 19:16, Benjamin Kramer <benny.kra at googlemail.com> wrote:
>> 
>>> Author: d0k
>>> Date: Tue Nov 27 12:16:32 2012
>>> New Revision: 168711
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=168711&view=rev
>>> Log:
>>> SCEV: Even if the latch terminator is foldable we can't deduce the result of an unrelated condition with it.
>>> 
>>> Fixes PR14432.
>> 
>> Chris, can you approve this for 3.2? It fixes a miscompilation and is apparently a regression from 3.1.
>> 
>> - Ben
>> 
>>> 
>>> Modified:
>>>   llvm/trunk/lib/Analysis/ScalarEvolution.cpp
>>>   llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll
>>> 
>>> Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=168711&r1=168710&r2=168711&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
>>> +++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Tue Nov 27 12:16:32 2012
>>> @@ -6149,9 +6149,10 @@
>>>  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) {
>>> 
>>> Modified: llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll?rev=168711&r1=168710&r2=168711&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll (original)
>>> +++ llvm/trunk/test/Transforms/IndVarSimplify/eliminate-comparison.ll Tue Nov 27 12:16:32 2012
>>> @@ -106,3 +106,57 @@
>>> 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
>>> 
>>> 
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>> 
>> 
>> 
>