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[SimplifyCFG] fix accessing deleted PHINodes in switch-to-table conversion. 

When we have a covered lookup table, make sure we don't delete PHINodes that
are cached in PHIs.

rdar://17887153

llvm-svn: 214642
This commit is contained in:
Manman Ren 2014-08-02 23:41:54 +00:00
parent 0670abdd2e
commit 062f58d550
2 changed files with 54 additions and 1 deletions
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5
llvm/lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -3830,7 +3830,10 @@ static bool SwitchToLookupTable(SwitchInst *SI,
const bool GeneratingCoveredLookupTable = MaxTableSize == TableSize;
if (GeneratingCoveredLookupTable) {
Builder.CreateBr(LookupBB);
SI->getDefaultDest()->removePredecessor(SI->getParent());
// We cached PHINodes in PHIs, to avoid accessing deleted PHINodes later,
// do not delete PHINodes here.
SI->getDefaultDest()->removePredecessor(SI->getParent(),
true/*DontDeleteUselessPHIs*/);
} else {
Value *Cmp = Builder.CreateICmpULT(TableIndex, ConstantInt::get(
MinCaseVal->getType(), TableSize));

50
llvm/test/Transforms/SimplifyCFG/X86/switch-covered-bug.ll Normal file
View File

@ -0,0 +1,50 @@
; RUN: opt -S -simplifycfg < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
; rdar://17887153
target datalayout = "e-p:64:64:64-S128-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f16:16:16-f32:32:32-f64:64:64-f128:128:128-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-darwin12.0.0"
; When we have a covered lookup table, make sure we don't delete PHINodes that
; are cached in PHIs.
; CHECK-LABEL: @test
; CHECK: entry:
; CHECK-NEXT: sub i3 %arg, -4
; CHECK-NEXT: zext i3 %switch.tableidx to i4
; CHECK-NEXT: getelementptr inbounds [8 x i64]* @switch.table, i32 0, i4 %switch.tableidx.zext
; CHECK-NEXT: load i64* %switch.gep
; CHECK-NEXT: add i64
; CHECK-NEXT: ret i64
define i64 @test(i3 %arg) {
entry:
switch i3 %arg, label %Default [
i3 -2, label %Label6
i3 1, label %Label1
i3 2, label %Label2
i3 3, label %Label3
i3 -4, label %Label4
i3 -3, label %Label5
]
Default:
%v1 = phi i64 [ 7, %Label6 ], [ 11, %Label5 ], [ 6, %Label4 ], [ 13, %Label3 ], [ 9, %Label2 ], [ 15, %Label1 ], [ 8, %entry ]
%v2 = phi i64 [ 0, %Label6 ], [ 0, %Label5 ], [ 0, %Label4 ], [ 0, %Label3 ], [ 0, %Label2 ], [ 0, %Label1 ], [ 0, %entry ]
%v3 = add i64 %v1, %v2
ret i64 %v3
Label1:
br label %Default
Label2:
br label %Default
Label3:
br label %Default
Label4:
br label %Default
Label5:
br label %Default
Label6:
br label %Default
}