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Fix: SLPVectorizer crashes with assertion when vectorizing a cmp instruction. 

The commit r225977 uncovered this bug. The problem was that the vectorizer tried to
read the second operand of an already deleted instruction.
The bug didn't show up before r225977 because the freed memory still contained a non-null pointer.
With r225977 deletion of instructions is delayed and the read operand pointer is always null.

llvm-svn: 227800
This commit is contained in:
Erik Eckstein 2015-02-02 12:45:34 +00:00
parent 82cd135738
commit 7330e358f6
2 changed files with 57 additions and 0 deletions
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1
llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
View File

@ -3943,6 +3943,7 @@ bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
// and the iterator may become invalid value.
it = BB->begin();
e = BB->end();
break;
}
}
}

56
llvm/test/Transforms/SLPVectorizer/X86/crash_cmpop.ll Normal file
View File

@ -0,0 +1,56 @@
; RUN: opt < %s -basicaa -slp-vectorizer -S
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.10.0"
define void @testfunc(float* nocapture %dest, float* nocapture readonly %src) {
entry:
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
%acc1.056 = phi float [ 0.000000e+00, %entry ], [ %add13, %for.body ]
%s1.055 = phi float [ 0.000000e+00, %entry ], [ %cond.i40, %for.body ]
%s0.054 = phi float [ 0.000000e+00, %entry ], [ %cond.i44, %for.body ]
%arrayidx = getelementptr inbounds float* %src, i64 %indvars.iv
%0 = load float* %arrayidx, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%arrayidx2 = getelementptr inbounds float* %dest, i64 %indvars.iv
store float %acc1.056, float* %arrayidx2, align 4
%add = fadd float %s0.054, %0
%add3 = fadd float %s1.055, %0
%mul = fmul float %s0.054, 0.000000e+00
%add4 = fadd float %mul, %add3
%mul5 = fmul float %s1.055, 0.000000e+00
%add6 = fadd float %mul5, %add
%cmp.i = fcmp olt float %add6, 1.000000e+00
%cond.i = select i1 %cmp.i, float %add6, float 1.000000e+00
%cmp.i51 = fcmp olt float %cond.i, -1.000000e+00
%cmp.i49 = fcmp olt float %add4, 1.000000e+00
%cond.i50 = select i1 %cmp.i49, float %add4, float 1.000000e+00
%cmp.i47 = fcmp olt float %cond.i50, -1.000000e+00
%cond.i.op = fmul float %cond.i, 0.000000e+00
%mul10 = select i1 %cmp.i51, float -0.000000e+00, float %cond.i.op
%cond.i50.op = fmul float %cond.i50, 0.000000e+00
%mul11 = select i1 %cmp.i47, float -0.000000e+00, float %cond.i50.op
%add13 = fadd float %mul10, %mul11
; The SLPVectorizer crashed in vectorizeChainsInBlock() because it tried
; to access the second operand of the following cmp after the cmp itself
; was already vectorized and deleted.
%cmp.i45 = fcmp olt float %add13, 1.000000e+00
%cond.i46 = select i1 %cmp.i45, float %add13, float 1.000000e+00
%cmp.i43 = fcmp olt float %cond.i46, -1.000000e+00
%cond.i44 = select i1 %cmp.i43, float -1.000000e+00, float %cond.i46
%cmp.i41 = fcmp olt float %mul11, 1.000000e+00
%cond.i42 = select i1 %cmp.i41, float %mul11, float 1.000000e+00
%cmp.i39 = fcmp olt float %cond.i42, -1.000000e+00
%cond.i40 = select i1 %cmp.i39, float -1.000000e+00, float %cond.i42
%exitcond = icmp eq i64 %indvars.iv.next, 32
br i1 %exitcond, label %for.end, label %for.body
for.end:
ret void
}