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Revert r223049, r223050 and r223051 while investigating test failures.

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I didn't foresee affecting the Clang test suite :/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223054 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hans Wennborg 2014-12-01 17:36:43 +00:00
parent 07c6024f48
commit c9605b6067
7 changed files with 112 additions and 144 deletions
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59
lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
View File

@ -2695,57 +2695,32 @@ void SelectionDAGBuilder::visitSwitch(const SwitchInst &SI) {
if (SwitchMBB + 1 != FuncInfo.MF->end())
NextBlock = SwitchMBB + 1;
// Create a vector of Cases, sorted so that we can efficiently create a binary
// search tree from them.
CaseVector Cases;
Clusterify(Cases, SI);
// Get the default destination MBB.
MachineBasicBlock *Default = FuncInfo.MBBMap[SI.getDefaultDest()];
if (isa<UnreachableInst>(SI.getDefaultDest()->getFirstNonPHIOrDbg())) {
// Replace an unreachable default destination with the most popular case
// destination.
DenseMap<const BasicBlock*, uint64_t> Popularity;
uint64_t MaxPop = 0;
const BasicBlock *MaxBB = nullptr;
for (auto I : SI.cases()) {
const BasicBlock *BB = I.getCaseSuccessor();
if (++Popularity[BB] > MaxPop) {
MaxPop = Popularity[BB];
MaxBB = BB;
}
}
// Set new default.
Default = FuncInfo.MBBMap[MaxBB];
// Remove cases that have been replaced by the default.
CaseItr I = Cases.begin();
while (I != Cases.end()) {
if (I->BB == Default) {
I = Cases.erase(I);
continue;
}
++I;
}
}
// If there is only the default destination, go there directly.
if (Cases.empty()) {
// If there is only the default destination, branch to it if it is not the
// next basic block. Otherwise, just fall through.
if (!SI.getNumCases()) {
// Update machine-CFG edges.
SwitchMBB->addSuccessor(Default);
// If this is not a fall-through branch, emit the branch.
if (Default != NextBlock) {
DAG.setRoot(DAG.getNode(ISD::BR, getCurSDLoc(), MVT::Other,
getControlRoot(), DAG.getBasicBlock(Default)));
}
if (Default != NextBlock)
DAG.setRoot(DAG.getNode(ISD::BR, getCurSDLoc(),
MVT::Other, getControlRoot(),
DAG.getBasicBlock(Default)));
return;
}
// Get the Value to be switched on.
// If there are any non-default case statements, create a vector of Cases
// representing each one, and sort the vector so that we can efficiently
// create a binary search tree from them.
CaseVector Cases;
Clusterify(Cases, SI);
// Get the Value to be switched on and default basic blocks, which will be
// inserted into CaseBlock records, representing basic blocks in the binary
// search tree.
const Value *SV = SI.getCondition();
// Push the initial CaseRec onto the worklist

64
lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -3120,6 +3120,55 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
--i; --e;
Changed = true;
}
// If the default value is unreachable, figure out the most popular
// destination and make it the default.
if (SI->getDefaultDest() == BB) {
std::map<BasicBlock*, std::pair<unsigned, unsigned> > Popularity;
for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
i != e; ++i) {
std::pair<unsigned, unsigned> &entry =
Popularity[i.getCaseSuccessor()];
if (entry.first == 0) {
entry.first = 1;
entry.second = i.getCaseIndex();
} else {
entry.first++;
}
}
// Find the most popular block.
unsigned MaxPop = 0;
unsigned MaxIndex = 0;
BasicBlock *MaxBlock = nullptr;
for (std::map<BasicBlock*, std::pair<unsigned, unsigned> >::iterator
I = Popularity.begin(), E = Popularity.end(); I != E; ++I) {
if (I->second.first > MaxPop ||
(I->second.first == MaxPop && MaxIndex > I->second.second)) {
MaxPop = I->second.first;
MaxIndex = I->second.second;
MaxBlock = I->first;
}
}
if (MaxBlock) {
// Make this the new default, allowing us to delete any explicit
// edges to it.
SI->setDefaultDest(MaxBlock);
Changed = true;
// If MaxBlock has phinodes in it, remove MaxPop-1 entries from
// it.
if (isa<PHINode>(MaxBlock->begin()))
for (unsigned i = 0; i != MaxPop-1; ++i)
MaxBlock->removePredecessor(SI->getParent());
for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
i != e; ++i)
if (i.getCaseSuccessor() == MaxBlock) {
SI->removeCase(i);
--i; --e;
}
}
}
} else if (InvokeInst *II = dyn_cast<InvokeInst>(TI)) {
if (II->getUnwindDest() == BB) {
// Convert the invoke to a call instruction. This would be a good
@ -4134,20 +4183,19 @@ static bool SwitchToLookupTable(SwitchInst *SI,
"It is impossible for a switch to have more entries than the max "
"representable value of its input integer type's size.");
// If the default destination is unreachable, or if the lookup table covers
// all values of the conditional variable, branch directly to the lookup table
// BB. Otherwise, check that the condition is within the case range.
const bool DefaultIsReachable =
!isa<UnreachableInst>(SI->getDefaultDest()->getFirstNonPHIOrDbg());
const bool GeneratingCoveredLookupTable = (MaxTableSize == TableSize);
// If we have a fully covered lookup table, unconditionally branch to the
// lookup table BB. Otherwise, check if the condition value is within the case
// range. If it is so, branch to the new BB. Otherwise branch to SI's default
// destination.
BranchInst *RangeCheckBranch = nullptr;
if (!DefaultIsReachable || GeneratingCoveredLookupTable) {
const bool GeneratingCoveredLookupTable = MaxTableSize == TableSize;
if (GeneratingCoveredLookupTable) {
Builder.CreateBr(LookupBB);
// We cached PHINodes in PHIs, to avoid accessing deleted PHINodes later,
// do not delete PHINodes here.
SI->getDefaultDest()->removePredecessor(SI->getParent(),
true /*DontDeleteUselessPHIs*/);
true/*DontDeleteUselessPHIs*/);
} else {
Value *Cmp = Builder.CreateICmpULT(TableIndex, ConstantInt::get(
MinCaseVal->getType(), TableSize));

6
test/CodeGen/X86/2013-10-14-FastISel-incorrect-vreg.ll
View File

@ -41,7 +41,7 @@ entry:
i1 false, label %label_end
]
default:
br label %label_end
unreachable
label_true:
br label %label_end
@ -80,7 +80,7 @@ entry:
i1 false, label %label_end
]
default:
br label %label_end
unreachable
label_true:
br label %label_end
@ -119,7 +119,7 @@ entry:
i1 false, label %label_end
]
default:
br label %label_end
unreachable
label_true:
br label %label_end

6
test/CodeGen/X86/asm-label.ll
View File

@ -24,7 +24,7 @@ if.end: ; preds = %if.then
br label %cleanup
cleanup: ; preds = %if.end, %if.then9
switch i32 undef, label %default [
switch i32 undef, label %unreachable [
i32 0, label %cleanup.cont
i32 1, label %if.end11
]
@ -35,6 +35,6 @@ cleanup.cont: ; preds = %cleanup
if.end11: ; preds = %cleanup.cont, %cleanup, %land.lhs.true, %entry
ret void
default: ; preds = %cleanup
br label %if.end11
unreachable: ; preds = %cleanup
unreachable
}

52
test/CodeGen/X86/switch-jump-table.ll
View File

@ -1,52 +0,0 @@
; RUN: llc -march=x86 < %s | FileCheck %s
; An unreachable default destination is replaced with the most popular case label.
define void @sum2(i32 %x, i32* %to) {
; CHECK-LABEL: sum2:
; CHECK: movl 4(%esp), [[REG:%e[a-z]{2}]]
; cmpl $3, [[REG]]
; CHECK: jbe .LBB0_1
; CHECK: movl $4
; CHECK: retl
; CHECK-LABEL: .LBB0_1:
; CHECK-NEXT: jmpl *.LJTI0_0(,[[REG]],4)
entry:
switch i32 %x, label %default [
i32 0, label %bb0
i32 1, label %bb1
i32 2, label %bb2
i32 3, label %bb3
i32 4, label %bb4
i32 5, label %bb4
]
bb0:
store i32 0, i32* %to
br label %exit
bb1:
store i32 1, i32* %to
br label %exit
bb2:
store i32 2, i32* %to
br label %exit
bb3:
store i32 3, i32* %to
br label %exit
bb4:
store i32 4, i32* %to
br label %exit
exit:
ret void
default:
unreachable
; The jump table has four entries.
; CHECK-LABEL: .LJTI0_0:
; CHECK-NEXT: .long .LBB0_2
; CHECK-NEXT: .long .LBB0_3
; CHECK-NEXT: .long .LBB0_4
; CHECK-NEXT: .long .LBB0_5
; CHECK-NOT: .long
}

26
test/Transforms/SimplifyCFG/UnreachableEliminate.ll
View File

@ -46,6 +46,32 @@ T:
ret i32 2
}
; PR9450
define i32 @test4(i32 %v, i32 %w) {
; CHECK: entry:
; CHECK-NEXT: switch i32 %v, label %T [
; CHECK-NEXT: i32 3, label %V
; CHECK-NEXT: i32 2, label %U
; CHECK-NEXT: ]
entry:
br label %SWITCH
V:
ret i32 7
SWITCH:
switch i32 %v, label %default [
i32 1, label %T
i32 2, label %U
i32 3, label %V
]
default:
unreachable
U:
ret i32 %w
T:
ret i32 2
}
;; We can either convert the following control-flow to a select or remove the
;; unreachable control flow because of the undef store of null. Make sure we do

43
test/Transforms/SimplifyCFG/X86/switch_to_lookup_table.ll
View File

@ -21,8 +21,8 @@ target triple = "x86_64-unknown-linux-gnu"
; The table for @cprop
; CHECK: @switch.table5 = private unnamed_addr constant [7 x i32] [i32 5, i32 42, i32 126, i32 -452, i32 128, i32 6, i32 7]
; The table for @unreachable_case
; CHECK: @switch.table6 = private unnamed_addr constant [9 x i32] [i32 0, i32 0, i32 0, i32 2, i32 -1, i32 1, i32 1, i32 1, i32 1]
; The table for @unreachable
; CHECK: @switch.table6 = private unnamed_addr constant [5 x i32] [i32 0, i32 0, i32 0, i32 1, i32 -1]
; A simple int-to-int selection switch.
; It is dense enough to be replaced by table lookup.
@ -752,7 +752,7 @@ return:
; CHECK: %switch.gep = getelementptr inbounds [7 x i32]* @switch.table5, i32 0, i32 %switch.tableidx
}
define i32 @unreachable_case(i32 %x) {
define i32 @unreachable(i32 %x) {
entry:
switch i32 %x, label %sw.default [
i32 0, label %sw.bb
@ -770,44 +770,15 @@ sw.bb: br label %return
sw.bb1: unreachable
sw.bb2: br label %return
sw.bb3: br label %return
sw.default: br label %return
sw.default: unreachable
return:
%retval.0 = phi i32 [ 1, %sw.bb3 ], [ -1, %sw.bb2 ], [ 0, %sw.bb ], [ 2, %sw.default ]
%retval.0 = phi i32 [ 1, %sw.bb3 ], [ -1, %sw.bb2 ], [ 0, %sw.bb ]
ret i32 %retval.0
; CHECK-LABEL: @unreachable_case(
; CHECK-LABEL: @unreachable(
; CHECK: switch.lookup:
; CHECK: getelementptr inbounds [9 x i32]* @switch.table6, i32 0, i32 %switch.tableidx
}
define i32 @unreachable_default(i32 %x) {
entry:
switch i32 %x, label %default [
i32 0, label %bb0
i32 1, label %bb1
i32 2, label %bb2
i32 3, label %bb3
]
bb0: br label %return
bb1: br label %return
bb2: br label %return
bb3: br label %return
default: unreachable
return:
%retval = phi i32 [ 42, %bb0 ], [ 52, %bb1 ], [ 1, %bb2 ], [ 2, %bb3 ]
ret i32 %retval
; CHECK-LABEL: @unreachable_default(
; CHECK: entry:
; CHECK-NEXT: %switch.tableidx = sub i32 %x, 0
; CHECK-NOT: icmp
; CHECK-NOT: br 1i
; CHECK-NEXT: %switch.gep = getelementptr inbounds [4 x i32]* @switch.table7, i32 0, i32 %switch.tableidx
; CHECK-NEXT: %switch.load = load i32* %switch.gep
; CHECK-NEXT: ret i32 %switch.load
; CHECK: getelementptr inbounds [5 x i32]* @switch.table6, i32 0, i32 %switch.tableidx
}
; Don't create a table with illegal type