[llvm] r278217 - [LVI] Relax the assertion about LVILatticeVal type in getConstantRange

[Artur Pilipenko via llvm-commits]

Author: apilipenko
Date: Wed Aug 10 07:54:54 2016
New Revision: 278217

URL: http://llvm.org/viewvc/llvm-project?rev=278217&view=rev
Log:
[LVI] Relax the assertion about LVILatticeVal type in getConstantRange

The problem was triggered by my recent change in CVP (D23059). Current code expected that integer constants are represented by constantrange LVILatticeVal and never represented as LVILatticeVal with constant tag. That is true for ConstantInt constants, although ConstantExpr integer type constants are legally represented as constant LVILatticeVal.

This code fails with CVP change in:

@b = global i32 0, align 4
define void @test6(i32 %a) {
bb:
  %add = add i32 %a, ptrtoint (i32* @b to i32)
  ret void
}
Currently getConstantRange code is not executed by any of the upstream passes. I'm going to add a test case to test/Transforms/CorrelatedValuePropagation/add.ll once I resubmit the CVP change.

Reviewed By: sanjoy

Differential Revision: http://reviews.llvm.org/D23194

Modified:
    llvm/trunk/lib/Analysis/LazyValueInfo.cpp

Modified: llvm/trunk/lib/Analysis/LazyValueInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LazyValueInfo.cpp?rev=278217&r1=278216&r2=278217&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LazyValueInfo.cpp (original)
+++ llvm/trunk/lib/Analysis/LazyValueInfo.cpp Wed Aug 10 07:54:54 2016
@@ -1537,11 +1537,14 @@ ConstantRange LazyValueInfo::getConstant
   const DataLayout &DL = BB->getModule()->getDataLayout();
   LVILatticeVal Result =
       getCache(PImpl, AC, &DL, DT).getValueInBlock(V, BB, CxtI);
-  assert(!Result.isConstant());
   if (Result.isUndefined())
     return ConstantRange(Width, /*isFullSet=*/false);
   if (Result.isConstantRange())
     return Result.getConstantRange();
+  // We represent ConstantInt constants as constant ranges but other kinds
+  // of integer constants, i.e. ConstantExpr will be tagged as constants
+  assert(!(Result.isConstant() && isa<ConstantInt>(Result.getConstant())) &&
+         "ConstantInt value must be represented as constantrange");
   return ConstantRange(Width, /*isFullSet=*/true);
 }