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SimplifyCFG: Don't duplicate calls to functions marked noduplicate v2

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v2:
  - Use CI->cannotDuplicate()

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193115 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tom Stellard 2013-10-21 20:07:30 +00:00
parent e161dc28a8
commit f2089e1dd8
2 changed files with 52 additions and 0 deletions
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15
lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -1561,6 +1561,19 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB) {
return true;
}
/// \returns True if this block contains a CallInst with the NoDuplicate
/// attribute.
static bool HasNoDuplicateCall(const BasicBlock *BB) {
for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
const CallInst *CI = dyn_cast<CallInst>(I);
if (!CI)
continue;
if (CI->cannotDuplicate())
return true;
}
return false;
}
/// BlockIsSimpleEnoughToThreadThrough - Return true if we can thread a branch
/// across this block.
static bool BlockIsSimpleEnoughToThreadThrough(BasicBlock *BB) {
@ -1608,6 +1621,8 @@ static bool FoldCondBranchOnPHI(BranchInst *BI, const DataLayout *TD) {
// Now we know that this block has multiple preds and two succs.
if (!BlockIsSimpleEnoughToThreadThrough(BB)) return false;
if (HasNoDuplicateCall(BB)) return false;
// Okay, this is a simple enough basic block. See if any phi values are
// constants.
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {

37
test/Transforms/SimplifyCFG/attr-noduplicate.ll Normal file
View File

@ -0,0 +1,37 @@
; RUN: opt < %s -simplifycfg -S | FileCheck %s
; This test checks that the SimplifyCFG pass won't duplicate a call to a
; function marked noduplicate.
;
; CHECK-LABEL: @noduplicate
; CHECK: call void @barrier
; CHECK-NOT: call void @barrier
define void @noduplicate(i32 %cond, i32* %out) {
entry:
%out1 = getelementptr i32* %out, i32 1
%out2 = getelementptr i32* %out, i32 2
%cmp = icmp eq i32 %cond, 0
br i1 %cmp, label %if.then, label %if.end
if.then:
store i32 5, i32* %out
br label %if.end
if.end:
call void @barrier() #0
br i1 %cmp, label %cond.end, label %cond.false
cond.false:
store i32 5, i32* %out1
br label %cond.end
cond.end:
%value = phi i32 [ 1, %cond.false ], [ 0, %if.end ]
store i32 %value, i32* %out2
ret void
}
; Function Attrs: noduplicate nounwind
declare void @barrier() #0
attributes #0 = { noduplicate nounwind }