[llvm] r240414 - [MachineBasicBlock] Add getFirstNonDebugInstr to complement getLastNonDebugInstr
Benjamin Kramer
benny.kra at googlemail.com
Tue Jun 23 07:47:30 PDT 2015
Author: d0k
Date: Tue Jun 23 09:47:29 2015
New Revision: 240414
URL: http://llvm.org/viewvc/llvm-project?rev=240414&view=rev
Log:
[MachineBasicBlock] Add getFirstNonDebugInstr to complement getLastNonDebugInstr
Use it in CodeGen where applicable. No functionality change intended.
Modified:
llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
llvm/trunk/lib/CodeGen/BranchFolding.cpp
llvm/trunk/lib/CodeGen/IfConversion.cpp
llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
llvm/trunk/lib/CodeGen/TailDuplication.cpp
Modified: llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h?rev=240414&r1=240413&r2=240414&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h Tue Jun 23 09:47:29 2015
@@ -469,6 +469,13 @@ public:
/// and return an instr_iterator instead.
instr_iterator getFirstInstrTerminator();
+ /// getFirstNonDebugInstr - returns an iterator to the first non-debug
+ /// instruction in the basic block, or end()
+ iterator getFirstNonDebugInstr();
+ const_iterator getFirstNonDebugInstr() const {
+ return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr();
+ }
+
/// getLastNonDebugInstr - returns an iterator to the last non-debug
/// instruction in the basic block, or end()
iterator getLastNonDebugInstr();
Modified: llvm/trunk/lib/CodeGen/BranchFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/BranchFolding.cpp?rev=240414&r1=240413&r2=240414&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/BranchFolding.cpp (original)
+++ llvm/trunk/lib/CodeGen/BranchFolding.cpp Tue Jun 23 09:47:29 2015
@@ -304,17 +304,9 @@ static unsigned HashMachineInstr(const M
/// HashEndOfMBB - Hash the last instruction in the MBB.
static unsigned HashEndOfMBB(const MachineBasicBlock *MBB) {
- MachineBasicBlock::const_iterator I = MBB->end();
- if (I == MBB->begin())
- return 0; // Empty MBB.
-
- --I;
- // Skip debug info so it will not affect codegen.
- while (I->isDebugValue()) {
- if (I == MBB->begin())
- return 0; // MBB empty except for debug info.
- --I;
- }
+ MachineBasicBlock::const_iterator I = MBB->getLastNonDebugInstr();
+ if (I == MBB->end())
+ return 0;
return HashMachineInstr(I);
}
@@ -1123,25 +1115,15 @@ bool BranchFolder::OptimizeBranches(Mach
// Blocks should be considered empty if they contain only debug info;
// else the debug info would affect codegen.
static bool IsEmptyBlock(MachineBasicBlock *MBB) {
- if (MBB->empty())
- return true;
- for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
- MBBI!=MBBE; ++MBBI) {
- if (!MBBI->isDebugValue())
- return false;
- }
- return true;
+ return MBB->getFirstNonDebugInstr() == MBB->end();
}
// Blocks with only debug info and branches should be considered the same
// as blocks with only branches.
static bool IsBranchOnlyBlock(MachineBasicBlock *MBB) {
- MachineBasicBlock::iterator MBBI, MBBE;
- for (MBBI = MBB->begin(), MBBE = MBB->end(); MBBI!=MBBE; ++MBBI) {
- if (!MBBI->isDebugValue())
- break;
- }
- return (MBBI->isBranch());
+ MachineBasicBlock::iterator I = MBB->getFirstNonDebugInstr();
+ assert(I != MBB->end() && "empty block!");
+ return I->isBranch();
}
/// IsBetterFallthrough - Return true if it would be clearly better to
@@ -1154,36 +1136,24 @@ static bool IsBetterFallthrough(MachineB
// MBB1 doesn't, we prefer to fall through into MBB1. This allows us to
// optimize branches that branch to either a return block or an assert block
// into a fallthrough to the return.
- if (IsEmptyBlock(MBB1) || IsEmptyBlock(MBB2)) return false;
+ MachineBasicBlock::iterator MBB1I = MBB1->getLastNonDebugInstr();
+ MachineBasicBlock::iterator MBB2I = MBB2->getLastNonDebugInstr();
+ if (MBB1I == MBB1->end() || MBB2I == MBB2->end())
+ return false;
// If there is a clear successor ordering we make sure that one block
// will fall through to the next
if (MBB1->isSuccessor(MBB2)) return true;
if (MBB2->isSuccessor(MBB1)) return false;
- // Neither block consists entirely of debug info (per IsEmptyBlock check),
- // so we needn't test for falling off the beginning here.
- MachineBasicBlock::iterator MBB1I = --MBB1->end();
- while (MBB1I->isDebugValue())
- --MBB1I;
- MachineBasicBlock::iterator MBB2I = --MBB2->end();
- while (MBB2I->isDebugValue())
- --MBB2I;
return MBB2I->isCall() && !MBB1I->isCall();
}
/// getBranchDebugLoc - Find and return, if any, the DebugLoc of the branch
-/// instructions on the block. Always use the DebugLoc of the first
-/// branching instruction found unless its absent, in which case use the
-/// DebugLoc of the second if present.
+/// instructions on the block.
static DebugLoc getBranchDebugLoc(MachineBasicBlock &MBB) {
- MachineBasicBlock::iterator I = MBB.end();
- if (I == MBB.begin())
- return DebugLoc();
- --I;
- while (I->isDebugValue() && I != MBB.begin())
- --I;
- if (I->isBranch())
+ MachineBasicBlock::iterator I = MBB.getLastNonDebugInstr();
+ if (I != MBB.end() && I->isBranch())
return I->getDebugLoc();
return DebugLoc();
}
@@ -1408,19 +1378,10 @@ ReoptimizeBlock:
// If the only things remaining in the block are debug info, remove these
// as well, so this will behave the same as an empty block in non-debug
// mode.
- if (!MBB->empty()) {
- bool NonDebugInfoFound = false;
- for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
- I != E; ++I) {
- if (!I->isDebugValue()) {
- NonDebugInfoFound = true;
- break;
- }
- }
- if (!NonDebugInfoFound)
- // Make the block empty, losing the debug info (we could probably
- // improve this in some cases.)
- MBB->erase(MBB->begin(), MBB->end());
+ if (IsEmptyBlock(MBB)) {
+ // Make the block empty, losing the debug info (we could probably
+ // improve this in some cases.)
+ MBB->erase(MBB->begin(), MBB->end());
}
// If this block is just an unconditional branch to CurTBB, we can
// usually completely eliminate the block. The only case we cannot
Modified: llvm/trunk/lib/CodeGen/IfConversion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/IfConversion.cpp?rev=240414&r1=240413&r2=240414&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/IfConversion.cpp (original)
+++ llvm/trunk/lib/CodeGen/IfConversion.cpp Tue Jun 23 09:47:29 2015
@@ -1355,15 +1355,9 @@ bool IfConverter::IfConvertDiamond(BBInf
Redefs.addLiveIns(BBI1->BB);
// Remove the duplicated instructions at the beginnings of both paths.
- MachineBasicBlock::iterator DI1 = BBI1->BB->begin();
- MachineBasicBlock::iterator DI2 = BBI2->BB->begin();
- MachineBasicBlock::iterator DIE1 = BBI1->BB->end();
- MachineBasicBlock::iterator DIE2 = BBI2->BB->end();
// Skip dbg_value instructions
- while (DI1 != DIE1 && DI1->isDebugValue())
- ++DI1;
- while (DI2 != DIE2 && DI2->isDebugValue())
- ++DI2;
+ MachineBasicBlock::iterator DI1 = BBI1->BB->getFirstNonDebugInstr();
+ MachineBasicBlock::iterator DI2 = BBI2->BB->getFirstNonDebugInstr();
BBI1->NonPredSize -= NumDups1;
BBI2->NonPredSize -= NumDups1;
Modified: llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp?rev=240414&r1=240413&r2=240414&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp Tue Jun 23 09:47:29 2015
@@ -180,6 +180,14 @@ MachineBasicBlock::instr_iterator Machin
return I;
}
+MachineBasicBlock::iterator MachineBasicBlock::getFirstNonDebugInstr() {
+ // Skip over begin-of-block dbg_value instructions.
+ iterator I = begin(), E = end();
+ while (I != E && I->isDebugValue())
+ ++I;
+ return I;
+}
+
MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() {
// Skip over end-of-block dbg_value instructions.
instr_iterator B = instr_begin(), I = instr_end();
Modified: llvm/trunk/lib/CodeGen/TailDuplication.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TailDuplication.cpp?rev=240414&r1=240413&r2=240414&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TailDuplication.cpp (original)
+++ llvm/trunk/lib/CodeGen/TailDuplication.cpp Tue Jun 23 09:47:29 2015
@@ -627,11 +627,8 @@ TailDuplicatePass::isSimpleBB(MachineBas
return false;
if (TailBB->pred_empty())
return false;
- MachineBasicBlock::iterator I = TailBB->begin();
- MachineBasicBlock::iterator E = TailBB->end();
- while (I != E && I->isDebugValue())
- ++I;
- if (I == E)
+ MachineBasicBlock::iterator I = TailBB->getFirstNonDebugInstr();
+ if (I == TailBB->end())
return true;
return I->isUnconditionalBranch();
}
More information about the llvm-commits
mailing list