diff options
| author | Dan Gohman <gohman@apple.com> | 2009-04-25 17:05:40 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2009-04-25 17:05:40 +0000 |
| commit | 2c73d5fb9e3d68c96bb2242bbbf2930a8db10343 (patch) | |
| tree | 7871a90ca0cb7812f7fe9a280dc3c92ea1adc2a5 | |
| parent | 4cdc44c82c4415b467760065fed146f73933c67b (diff) | |
Handle ands with 0 and shifts by 0 correctly. These aren't
common, but indvars shouldn't crash on them. This fixes PR4054.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70051 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 11 | ||||
| -rw-r--r-- | test/Transforms/IndVarSimplify/avoid-i0.ll | 23 |
2 files changed, 32 insertions, 2 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 409bad9166..495290d8d7 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -1754,6 +1754,8 @@ SCEVHandle ScalarEvolution::createSCEV(Value *V) { // For an expression like x&255 that merely masks off the high bits, // use zext(trunc(x)) as the SCEV expression. if (ConstantInt *CI = dyn_cast<ConstantInt>(U->getOperand(1))) { + if (CI->isNullValue()) + return getSCEV(U->getOperand(1)); const APInt &A = CI->getValue(); unsigned Ones = A.countTrailingOnes(); if (APIntOps::isMask(Ones, A)) @@ -1818,10 +1820,15 @@ SCEVHandle ScalarEvolution::createSCEV(Value *V) { if (Instruction *L = dyn_cast<Instruction>(U->getOperand(0))) if (L->getOpcode() == Instruction::Shl && L->getOperand(1) == U->getOperand(1)) { - uint64_t Amt = getTypeSizeInBits(U->getType()) - CI->getZExtValue(); + unsigned BitWidth = getTypeSizeInBits(U->getType()); + uint64_t Amt = BitWidth - CI->getZExtValue(); + if (Amt == BitWidth) + return getSCEV(L->getOperand(0)); // shift by zero --> noop + if (Amt > BitWidth) + return getIntegerSCEV(0, U->getType()); // value is undefined return getSignExtendExpr(getTruncateExpr(getSCEV(L->getOperand(0)), - IntegerType::get(Amt)), + IntegerType::get(Amt)), U->getType()); } break; diff --git a/test/Transforms/IndVarSimplify/avoid-i0.ll b/test/Transforms/IndVarSimplify/avoid-i0.ll new file mode 100644 index 0000000000..28112e75f5 --- /dev/null +++ b/test/Transforms/IndVarSimplify/avoid-i0.ll @@ -0,0 +1,23 @@ +; RUN: llvm-as < %s | opt -indvars +; PR4054 + +; Don't treat an and with 0 as a mask (trunc+zext). + +define i32 @int80(i8 signext %p_71) nounwind { +entry: + br label %bb + +bb: ; preds = %bb6, %entry + %p_71_addr.0 = phi i8 [ %p_71, %entry ], [ %0, %bb6 ] ; <i8> [#uses=0] + br i1 false, label %bb4, label %bb1 + +bb1: ; preds = %bb + ret i32 0 + +bb4: ; preds = %bb4, %bb + br i1 false, label %bb6, label %bb4 + +bb6: ; preds = %bb4 + %0 = and i8 0, 0 ; <i8> [#uses=1] + br label %bb +} |