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Handle a corner case with IV chain collection with bailout instead of assert.

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Fixes PR11783: bad cast to AddRecExpr.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148572 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick 2012-01-20 21:23:40 +00:00
parent a44919ef45
commit 0041d4d447
2 changed files with 49 additions and 2 deletions
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8
lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -2484,11 +2484,15 @@ void LSRInstance::ChainInstruction(Instruction *UserInst, Instruction *IVOper,
DEBUG(dbgs() << "IV Chain Limit\n");
return;
}
LastIncExpr = SE.getSCEV(NextIV);
// IVUsers may have skipped over sign/zero extensions. We don't currently
// attempt to form chains involving extensions unless they can be hoisted
// into this loop's AddRec.
if (!isa<SCEVAddRecExpr>(LastIncExpr))
return;
++NChains;
IVChainVec.resize(NChains);
ChainUsersVec.resize(NChains);
LastIncExpr = SE.getSCEV(NextIV);
assert(isa<SCEVAddRecExpr>(LastIncExpr) && "expect recurrence at IV user");
DEBUG(dbgs() << "IV Head: (" << *UserInst << ") IV=" << *LastIncExpr
<< "\n");
}

43
test/Transforms/LoopStrengthReduce/ivchain.ll Normal file
View File

@ -0,0 +1,43 @@
; RUN: opt < %s -loop-reduce -S | FileCheck %s
;
; PR11782: bad cast to AddRecExpr.
; A sign extend feeds an IVUser and cannot be hoisted into the AddRec.
; CollectIVChains should bailout on this case.
%struct = type { i8*, i8*, i16, i64, i16, i16, i16, i64, i64, i16, i8*, i64, i64, i64 }
; CHECK: @test
; CHECK: for.body:
; CHECK: lsr.iv = phi %struct
; CHECK: br
define i32 @test(i8* %h, i32 %more) nounwind uwtable {
entry:
br i1 undef, label %land.end238, label %return
land.end238: ; preds = %if.end229
br label %for.body
for.body: ; preds = %sw.epilog, %land.end238
%fbh.0 = phi %struct* [ undef, %land.end238 ], [ %incdec.ptr, %sw.epilog ]
%column_n.0 = phi i16 [ 0, %land.end238 ], [ %inc601, %sw.epilog ]
%conv250 = sext i16 %column_n.0 to i32
%add257 = add nsw i32 %conv250, 1
%conv258 = trunc i32 %add257 to i16
%cmp263 = icmp ult i16 undef, 2
br label %if.end388
if.end388: ; preds = %if.then380, %if.else356
%ColLength = getelementptr inbounds %struct* %fbh.0, i64 0, i32 7
%call405 = call signext i16 @SQLColAttribute(i8* undef, i16 zeroext %conv258, i16 zeroext 1003, i8* null, i16 signext 0, i16* null, i64* %ColLength) nounwind
br label %sw.epilog
sw.epilog: ; preds = %sw.bb542, %sw.bb523, %if.end475
%inc601 = add i16 %column_n.0, 1
%incdec.ptr = getelementptr inbounds %struct* %fbh.0, i64 1
br label %for.body
return: ; preds = %entry
ret i32 1
}
declare signext i16 @SQLColAttribute(i8*, i16 zeroext, i16 zeroext, i8*, i16 signext, i16*, i64*)