While hoisting instruction to speculatively execute simple bb, ignore dbg intrinsics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66255 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 2557961..7c71f46 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -943,11 +943,22 @@
static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *BB1) {
// Only speculatively execution a single instruction (not counting the
// terminator) for now.
- BasicBlock::iterator BBI = BB1->begin();
- ++BBI; // must have at least a terminator
- if (BBI == BB1->end()) return false; // only one inst
- ++BBI;
- if (BBI != BB1->end()) return false; // more than 2 insts.
+ Instruction *HInst = NULL;
+ Instruction *Term = BB1->getTerminator();
+ for (BasicBlock::iterator BBI = BB1->begin(), BBE = BB1->end();
+ BBI != BBE; ++BBI) {
+ Instruction *I = BBI;
+ // Skip debug info.
+ if (isa<DbgInfoIntrinsic>(I)) continue;
+ if (I == Term) break;
+
+ if (!HInst)
+ HInst = I;
+ else
+ return false;
+ }
+ if (!HInst)
+ return false;
// Be conservative for now. FP select instruction can often be expensive.
Value *BrCond = BI->getCondition();
@@ -976,13 +987,13 @@
// %t1 = icmp
// %t4 = add %t2, c
// %t3 = select i1 %t1, %t2, %t3
- Instruction *I = BB1->begin();
- switch (I->getOpcode()) {
+ switch (HInst->getOpcode()) {
default: return false; // Not safe / profitable to hoist.
case Instruction::Add:
case Instruction::Sub:
// FP arithmetic might trap. Not worth doing for vector ops.
- if (I->getType()->isFloatingPoint() || isa<VectorType>(I->getType()))
+ if (HInst->getType()->isFloatingPoint()
+ || isa<VectorType>(HInst->getType()))
return false;
break;
case Instruction::And:
@@ -992,14 +1003,14 @@
case Instruction::LShr:
case Instruction::AShr:
// Don't mess with vector operations.
- if (isa<VectorType>(I->getType()))
+ if (isa<VectorType>(HInst->getType()))
return false;
break; // These are all cheap and non-trapping instructions.
}
// If the instruction is obviously dead, don't try to predicate it.
- if (I->use_empty()) {
- I->eraseFromParent();
+ if (HInst->use_empty()) {
+ HInst->eraseFromParent();
return true;
}
@@ -1012,7 +1023,7 @@
Value *FalseV = NULL;
BasicBlock *BB2 = BB1->getTerminator()->getSuccessor(0);
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+ for (Value::use_iterator UI = HInst->use_begin(), E = HInst->use_end();
UI != E; ++UI) {
// Ignore any user that is not a PHI node in BB2. These can only occur in
// unreachable blocks, because they would not be dominated by the instr.
@@ -1033,7 +1044,8 @@
// Do not hoist the instruction if any of its operands are defined but not
// used in this BB. The transformation will prevent the operand from
// being sunk into the use block.
- for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) {
+ for (User::op_iterator i = HInst->op_begin(), e = HInst->op_end();
+ i != e; ++i) {
Instruction *OpI = dyn_cast<Instruction>(*i);
if (OpI && OpI->getParent() == BIParent &&
!OpI->isUsedInBasicBlock(BIParent))
@@ -1062,17 +1074,17 @@
}
} else
InsertPos = BI;
- BIParent->getInstList().splice(InsertPos, BB1->getInstList(), I);
+ BIParent->getInstList().splice(InsertPos, BB1->getInstList(), HInst);
// Create a select whose true value is the speculatively executed value and
// false value is the previously determined FalseV.
SelectInst *SI;
if (Invert)
- SI = SelectInst::Create(BrCond, FalseV, I,
- FalseV->getName() + "." + I->getName(), BI);
+ SI = SelectInst::Create(BrCond, FalseV, HInst,
+ FalseV->getName() + "." + HInst->getName(), BI);
else
- SI = SelectInst::Create(BrCond, I, FalseV,
- I->getName() + "." + FalseV->getName(), BI);
+ SI = SelectInst::Create(BrCond, HInst, FalseV,
+ HInst->getName() + "." + FalseV->getName(), BI);
// Make the PHI node use the select for all incoming values for "then" and
// "if" blocks.