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authorEvan Cheng <evan.cheng@apple.com>2011-04-27 19:32:43 +0000
committerEvan Cheng <evan.cheng@apple.com>2011-04-27 19:32:43 +0000
commit309db7c947de7f0f9730dff5f95bc1cc5bd1db7d (patch)
treef274f3ca9e79981b0157f28c874da2f367347c34
parentbddc1ca18a8ca23f6f145d2f5d006fa07e72a870 (diff)
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If converter was being too cute. It look for root BBs (which don't have
successors) and use inverse depth first search to traverse the BBs. However that doesn't work when the CFG has infinite loops. Simply do a linear traversal of all BBs work just fine. rdar://9344645 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130324 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/CodeGen/IfConversion.cpp21
-rw-r--r--test/CodeGen/ARM/2011-04-27-IfCvtBug.ll59
2 files changed, 62 insertions, 18 deletions
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index db53b0473a..790200b8df 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -27,7 +27,6 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
@@ -146,10 +145,6 @@ namespace {
: BBI(b), Kind(k), NeedSubsumption(s), NumDups(d), NumDups2(d2) {}
};
- /// Roots - Basic blocks that do not have successors. These are the starting
- /// points of Graph traversal.
- std::vector<MachineBasicBlock*> Roots;
-
/// BBAnalysis - Results of if-conversion feasibility analysis indexed by
/// basic block number.
std::vector<BBInfo> BBAnalysis;
@@ -287,11 +282,6 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
MF.RenumberBlocks();
BBAnalysis.resize(MF.getNumBlockIDs());
- // Look for root nodes, i.e. blocks without successors.
- for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
- if (I->succ_empty())
- Roots.push_back(I);
-
std::vector<IfcvtToken*> Tokens;
MadeChange = false;
unsigned NumIfCvts = NumSimple + NumSimpleFalse + NumTriangle +
@@ -406,7 +396,6 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
}
Tokens.clear();
- Roots.clear();
BBAnalysis.clear();
if (MadeChange && IfCvtBranchFold) {
@@ -924,13 +913,9 @@ IfConverter::BBInfo &IfConverter::AnalyzeBlock(MachineBasicBlock *BB,
/// candidates.
void IfConverter::AnalyzeBlocks(MachineFunction &MF,
std::vector<IfcvtToken*> &Tokens) {
- std::set<MachineBasicBlock*> Visited;
- for (unsigned i = 0, e = Roots.size(); i != e; ++i) {
- for (idf_ext_iterator<MachineBasicBlock*> I=idf_ext_begin(Roots[i],Visited),
- E = idf_ext_end(Roots[i], Visited); I != E; ++I) {
- MachineBasicBlock *BB = *I;
- AnalyzeBlock(BB, Tokens);
- }
+ for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
+ MachineBasicBlock *BB = I;
+ AnalyzeBlock(BB, Tokens);
}
// Sort to favor more complex ifcvt scheme.
diff --git a/test/CodeGen/ARM/2011-04-27-IfCvtBug.ll b/test/CodeGen/ARM/2011-04-27-IfCvtBug.ll
new file mode 100644
index 0000000000..0741049cff
--- /dev/null
+++ b/test/CodeGen/ARM/2011-04-27-IfCvtBug.ll
@@ -0,0 +1,59 @@
+; RUN: llc < %s -mtriple=thumbv7-apple-ios
+
+; If converter was being too cute. It look for root BBs (which don't have
+; successors) and use inverse depth first search to traverse the BBs. However
+; that doesn't work when the CFG has infinite loops. Simply do a linear
+; traversal of all BBs work just fine.
+
+; rdar://9344645
+
+%struct.hc = type { i32, i32, i32, i32 }
+
+define i32 @t(i32 %type) optsize {
+entry:
+ br i1 undef, label %if.then, label %if.else
+
+if.then:
+ unreachable
+
+if.else:
+ br i1 undef, label %if.then15, label %if.else18
+
+if.then15:
+ unreachable
+
+if.else18:
+ switch i32 %type, label %if.else173 [
+ i32 3, label %if.then115
+ i32 1, label %if.then102
+ ]
+
+if.then102:
+ br i1 undef, label %cond.true10.i, label %t.exit
+
+cond.true10.i:
+ br label %t.exit
+
+t.exit:
+ unreachable
+
+if.then115:
+ br i1 undef, label %if.else163, label %if.else145
+
+if.else145:
+ %call150 = call fastcc %struct.hc* @foo(%struct.hc* undef, i32 34865152) optsize
+ br label %while.body172
+
+if.else163:
+ %call168 = call fastcc %struct.hc* @foo(%struct.hc* undef, i32 34078720) optsize
+ br label %while.body172
+
+while.body172:
+ br label %while.body172
+
+if.else173:
+ ret i32 -1
+}
+
+declare hidden fastcc %struct.hc* @foo(%struct.hc* nocapture, i32) nounwind optsize
+