[llvm] r188832 - SLPVectorizer: Fix invalid iterator errors
Arnold Schwaighofer
aschwaighofer at apple.com
Tue Aug 20 14:21:46 PDT 2013
Author: arnolds
Date: Tue Aug 20 16:21:45 2013
New Revision: 188832
URL: http://llvm.org/viewvc/llvm-project?rev=188832&view=rev
Log:
SLPVectorizer: Fix invalid iterator errors
Update iterator when the SLP vectorizer changes the instructions in the basic
block by restarting the traversal of the basic block.
Patch by Yi Jiang!
Fixes PR 16899.
Added:
llvm/trunk/test/Transforms/SLPVectorizer/X86/pr16899.ll
Modified:
llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp
Modified: llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp?rev=188832&r1=188831&r2=188832&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp Tue Aug 20 16:21:45 2013
@@ -1875,6 +1875,8 @@ bool SLPVectorizer::tryToVectorize(Binar
bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
bool Changed = false;
SmallVector<Value *, 4> Incoming;
+ SmallSet<Instruction *, 16> VisitedInstrs;
+
// Collect the incoming values from the PHIs.
for (BasicBlock::iterator instr = BB->begin(), ie = BB->end(); instr != ie;
++instr) {
@@ -1883,9 +1885,21 @@ bool SLPVectorizer::vectorizeChainsInBlo
if (!P)
break;
+ // We may go through BB multiple times so skip the one we have checked.
+ if (VisitedInstrs.count(instr))
+ continue;
+ VisitedInstrs.insert(instr);
+
// Stop constructing the list when you reach a different type.
if (Incoming.size() && P->getType() != Incoming[0]->getType()) {
- Changed |= tryToVectorizeList(Incoming, R);
+ if (tryToVectorizeList(Incoming, R)) {
+ // We would like to start over since some instructions are deleted
+ // and the iterator may become invalid value.
+ Changed = true;
+ instr = BB->begin();
+ ie = BB->end();
+ }
+
Incoming.clear();
}
@@ -1895,14 +1909,20 @@ bool SLPVectorizer::vectorizeChainsInBlo
if (Incoming.size() > 1)
Changed |= tryToVectorizeList(Incoming, R);
- llvm::Instruction *I;
- for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e;) {
- I = it++;
- if (isa<DbgInfoIntrinsic>(I))
+ VisitedInstrs.clear();
+
+ for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; it++) {
+
+ // We may go through BB multiple times so skip the one we have checked.
+ if (VisitedInstrs.count(it))
+ continue;
+ VisitedInstrs.insert(it);
+
+ if (isa<DbgInfoIntrinsic>(it))
continue;
// Try to vectorize reductions that use PHINodes.
- if (PHINode *P = dyn_cast<PHINode>(I)) {
+ if (PHINode *P = dyn_cast<PHINode>(it)) {
// Check that the PHI is a reduction PHI.
if (P->getNumIncomingValues() != 2)
return Changed;
@@ -1919,20 +1939,38 @@ bool SLPVectorizer::vectorizeChainsInBlo
if (Inst == P)
Inst = BI->getOperand(1);
- Changed |= tryToVectorize(dyn_cast<BinaryOperator>(Inst), R);
+ if (tryToVectorize(dyn_cast<BinaryOperator>(Inst), R)) {
+ // We would like to start over since some instructions are deleted
+ // and the iterator may become invalid value.
+ Changed = true;
+ it = BB->begin();
+ e = BB->end();
+ }
continue;
}
// Try to vectorize trees that start at compare instructions.
- if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
+ if (CmpInst *CI = dyn_cast<CmpInst>(it)) {
if (tryToVectorizePair(CI->getOperand(0), CI->getOperand(1), R)) {
- Changed |= true;
+ Changed = true;
+ // We would like to start over since some instructions are deleted
+ // and the iterator may become invalid value.
+ it = BB->begin();
+ e = BB->end();
continue;
}
- for (int i = 0; i < 2; ++i)
- if (BinaryOperator *BI = dyn_cast<BinaryOperator>(CI->getOperand(i)))
- Changed |=
- tryToVectorizePair(BI->getOperand(0), BI->getOperand(1), R);
+
+ for (int i = 0; i < 2; ++i) {
+ if (BinaryOperator *BI = dyn_cast<BinaryOperator>(CI->getOperand(i))) {
+ if (tryToVectorizePair(BI->getOperand(0), BI->getOperand(1), R)) {
+ Changed = true;
+ // We would like to start over since some instructions are deleted
+ // and the iterator may become invalid value.
+ it = BB->begin();
+ e = BB->end();
+ }
+ }
+ }
continue;
}
}
Added: llvm/trunk/test/Transforms/SLPVectorizer/X86/pr16899.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SLPVectorizer/X86/pr16899.ll?rev=188832&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/SLPVectorizer/X86/pr16899.ll (added)
+++ llvm/trunk/test/Transforms/SLPVectorizer/X86/pr16899.ll Tue Aug 20 16:21:45 2013
@@ -0,0 +1,30 @@
+; RUN: opt < %s -slp-vectorizer -S -mtriple=i386--netbsd -mcpu=i486
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
+target triple = "i386--netbsd"
+
+ at a = common global i32* null, align 4
+
+; Function Attrs: noreturn nounwind readonly
+define i32 @fn1() #0 {
+entry:
+ %0 = load i32** @a, align 4, !tbaa !0
+ %1 = load i32* %0, align 4, !tbaa !3
+ %arrayidx1 = getelementptr inbounds i32* %0, i32 1
+ %2 = load i32* %arrayidx1, align 4, !tbaa !3
+ br label %do.body
+
+do.body: ; preds = %do.body, %entry
+ %c.0 = phi i32 [ %2, %entry ], [ %add2, %do.body ]
+ %b.0 = phi i32 [ %1, %entry ], [ %add, %do.body ]
+ %add = add nsw i32 %b.0, %c.0
+ %add2 = add nsw i32 %add, 1
+ br label %do.body
+}
+
+attributes #0 = { noreturn nounwind readonly "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!0 = metadata !{metadata !"any pointer", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}
+!3 = metadata !{metadata !"int", metadata !1}
+
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