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DependenceAnalysis: Don't crash if there is no constant operand. 

This makes the code match the comments. Resolves a crash in loop idiom (PR14219).

llvm-svn: 167110
This commit is contained in:
Benjamin Kramer 2012-10-31 09:20:38 +00:00
parent 2f728a9185
commit 24c643b6de
2 changed files with 29 additions and 3 deletions
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7
llvm/lib/Analysis/DependenceAnalysis.cpp
View File

@ -2278,11 +2278,12 @@ bool DependenceAnalysis::gcdMIVtest(const SCEV *Src,
assert(!Constant && "Surprised to find multiple constants");
Constant = cast<SCEVConstant>(Operand);
}
else if (isa<SCEVMulExpr>(Operand)) {
else if (const SCEVMulExpr *Product = dyn_cast<SCEVMulExpr>(Operand)) {
// Search for constant operand to participate in GCD;
// If none found; return false.
const SCEVConstant *ConstOp =
getConstantPart(cast<SCEVMulExpr>(Operand));
const SCEVConstant *ConstOp = getConstantPart(Product);
if (!ConstOp)
return false;
APInt ConstOpValue = ConstOp->getValue()->getValue();
ExtraGCD = APIntOps::GreatestCommonDivisor(ExtraGCD,
ConstOpValue.abs());

25
llvm/test/Transforms/LoopIdiom/crash.ll Normal file
View File

@ -0,0 +1,25 @@
; RUN: opt -basicaa -loop-idiom -S < %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.8.0"
; Don't crash inside DependenceAnalysis
; PR14219
define void @test1(i64* %iwork, i64 %x) {
bb0:
%mul116 = mul nsw i64 %x, %x
%incdec.ptr6.sum175 = add i64 42, %x
%arrayidx135 = getelementptr inbounds i64* %iwork, i64 %incdec.ptr6.sum175
br label %bb1
bb1:
%storemerge4226 = phi i64 [ 0, %bb0 ], [ %inc139, %bb1 ]
store i64 1, i64* %arrayidx135, align 8
%incdec.ptr6.sum176 = add i64 %mul116, %storemerge4226
%arrayidx137 = getelementptr inbounds i64* %iwork, i64 %incdec.ptr6.sum176
store i64 1, i64* %arrayidx137, align 8
%inc139 = add nsw i64 %storemerge4226, 1
%cmp131 = icmp sgt i64 %storemerge4226, 42
br i1 %cmp131, label %bb2, label %bb1
bb2:
ret void
}