Changes in directory llvm/lib/Transforms/Scalar:
LoopUnswitch.cpp updated: 1.18 -> 1.19
---
Log message:
pull some code out into a function
---
Diffs of the changes: (+28 -18)
LoopUnswitch.cpp | 46 ++++++++++++++++++++++++++++------------------
1 files changed, 28 insertions(+), 18 deletions(-)
Index: llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
diff -u llvm/lib/Transforms/Scalar/LoopUnswitch.cpp:1.18
llvm/lib/Transforms/Scalar/LoopUnswitch.cpp:1.19
--- llvm/lib/Transforms/Scalar/LoopUnswitch.cpp:1.18 Mon Feb 13 19:01:41 2006
+++ llvm/lib/Transforms/Scalar/LoopUnswitch.cpp Tue Feb 14 18:07:43 2006
@@ -432,6 +432,28 @@
return New;
}
+/// EmitPreheaderBranchOnCondition - Emit a conditional branch on two values
+/// if LIC == Val, branch to TrueDst, otherwise branch to FalseDest. Insert
the
+/// code immediately before InsertPt.
+static void EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
+ BasicBlock *TrueDest,
+ BasicBlock *FalseDest,
+ Instruction *InsertPt) {
+ // Insert a conditional branch on LIC to the two preheaders. The original
+ // code is the true version and the new code is the false version.
+ Value *BranchVal = LIC;
+ if (!isa<ConstantBool>(BranchVal)) {
+ BranchVal = BinaryOperator::createSetEQ(LIC, Val, "tmp", InsertPt);
+ } else if (Val != ConstantBool::True) {
+ // We want to enter the new loop when the condition is true.
+ std::swap(TrueDest, FalseDest);
+ }
+
+ // Insert the new branch.
+ new BranchInst(TrueDest, FalseDest, BranchVal, InsertPt);
+}
+
+
/// UnswitchTrivialCondition - Given a loop that has a trivial unswitchable
/// condition in it (a cond branch from its header block to its latch block,
/// where the path through the loop that doesn't execute its body has no
@@ -505,6 +527,7 @@
std::sort(ExitBlocks.begin(), ExitBlocks.end());
ExitBlocks.erase(std::unique(ExitBlocks.begin(), ExitBlocks.end()),
ExitBlocks.end());
+
// Split all of the edges from inside the loop to their exit blocks. This
// unswitching trivial: no phi nodes to update.
unsigned NumBlocks = L->getBlocks().size();
@@ -583,26 +606,13 @@
RemapInstruction(I, ValueMap);
// Rewrite the original preheader to select between versions of the loop.
- assert(isa<BranchInst>(OrigPreheader->getTerminator()) &&
- cast<BranchInst>(OrigPreheader->getTerminator())->isUnconditional() &&
- OrigPreheader->getTerminator()->getSuccessor(0) == LoopBlocks[0] &&
+ BranchInst *OldBR = cast<BranchInst>(OrigPreheader->getTerminator());
+ assert(OldBR->isUnconditional() && OldBR->getSuccessor(0) == LoopBlocks[0] &&
"Preheader splitting did not work correctly!");
- // Insert a conditional branch on LIC to the two preheaders. The original
- // code is the true version and the new code is the false version.
- Value *BranchVal = LIC;
- if (!isa<ConstantBool>(BranchVal)) {
- BranchVal = BinaryOperator::createSetEQ(LIC, Val, "tmp",
- OrigPreheader->getTerminator());
- } else if (Val != ConstantBool::True) {
- // We want to enter the new loop when the condition is true.
- BranchVal = BinaryOperator::createNot(BranchVal, "tmp",
- OrigPreheader->getTerminator());
- }
-
- // Remove the unconditional branch to LoopBlocks[0] and insert the new
branch.
- OrigPreheader->getInstList().pop_back();
- new BranchInst(NewBlocks[0], LoopBlocks[0], BranchVal, OrigPreheader);
+ // Emit the new branch that selects between the two versions of this loop.
+ EmitPreheaderBranchOnCondition(LIC, Val, NewBlocks[0], LoopBlocks[0], OldBR);
+ OldBR->eraseFromParent();
// Now we rewrite the original code to know that the condition is true and
the
// new code to know that the condition is false.
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