[llvm] r283134 - Refactor LICM pass in preparation for LoopSink pass.
Dehao Chen via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 3 11:52:09 PDT 2016
Author: dehao
Date: Mon Oct 3 13:52:08 2016
New Revision: 283134
URL: http://llvm.org/viewvc/llvm-project?rev=283134&view=rev
Log:
Refactor LICM pass in preparation for LoopSink pass.
Summary: LoopSink pass uses some common function in LICM. This patch refactor the LICM code to make it usable by LoopSink pass (https://reviews.llvm.org/D22778).
Reviewers: davidxl, danielcdh, hfinkel, chandlerc
Subscribers: hfinkel, llvm-commits
Differential Revision: https://reviews.llvm.org/D24168
Modified:
llvm/trunk/lib/Transforms/Scalar/LICM.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=283134&r1=283133&r2=283134&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Mon Oct 3 13:52:08 2016
@@ -101,7 +101,7 @@ CloneInstructionInExitBlock(Instruction
const LoopInfo *LI,
const LoopSafetyInfo *SafetyInfo);
static bool canSinkOrHoistInst(Instruction &I, AliasAnalysis *AA,
- DominatorTree *DT, TargetLibraryInfo *TLI,
+ DominatorTree *DT,
Loop *CurLoop, AliasSetTracker *CurAST,
LoopSafetyInfo *SafetyInfo);
@@ -337,7 +337,7 @@ bool llvm::sinkRegion(DomTreeNode *N, Al
// operands of the instruction are loop invariant.
//
if (isNotUsedInLoop(I, CurLoop, SafetyInfo) &&
- canSinkOrHoistInst(I, AA, DT, TLI, CurLoop, CurAST, SafetyInfo)) {
+ canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, SafetyInfo)) {
++II;
Changed |= sink(I, LI, DT, CurLoop, CurAST, SafetyInfo);
}
@@ -390,7 +390,7 @@ bool llvm::hoistRegion(DomTreeNode *N, A
// is safe to hoist the instruction.
//
if (CurLoop->hasLoopInvariantOperands(&I) &&
- canSinkOrHoistInst(I, AA, DT, TLI, CurLoop, CurAST, SafetyInfo) &&
+ canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, SafetyInfo) &&
isSafeToExecuteUnconditionally(
I, DT, CurLoop, SafetyInfo,
CurLoop->getLoopPreheader()->getTerminator()))
@@ -436,12 +436,16 @@ void llvm::computeLoopSafetyInfo(LoopSaf
SafetyInfo->BlockColors = colorEHFunclets(*Fn);
}
-/// canSinkOrHoistInst - Return true if the hoister and sinker can handle this
-/// instruction.
+/// Returns true if the hoister and sinker can handle this instruction.
+/// If SafetyInfo is nullptr, we are checking for sinking instructions from
+/// preheader to loop body (no speculation).
+/// If SafetyInfo is not nullptr, we are checking for hoisting/sinking
+/// instructions from loop body to preheader/exit. Check if the instruction
+/// can execute specultatively.
///
-bool canSinkOrHoistInst(Instruction &I, AliasAnalysis *AA, DominatorTree *DT,
- TargetLibraryInfo *TLI, Loop *CurLoop,
- AliasSetTracker *CurAST, LoopSafetyInfo *SafetyInfo) {
+bool canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
+ Loop *CurLoop, AliasSetTracker *CurAST,
+ LoopSafetyInfo *SafetyInfo) {
// Loads have extra constraints we have to verify before we can hoist them.
if (LoadInst *LI = dyn_cast<LoadInst>(&I)) {
if (!LI->isUnordered())
@@ -515,6 +519,11 @@ bool canSinkOrHoistInst(Instruction &I,
!isa<InsertValueInst>(I))
return false;
+ // SafetyInfo is nullptr if we are checking for sinking from preheader to
+ // loop body. It will be always safe as there is no speculative execution.
+ if (!SafetyInfo)
+ return true;
+
// TODO: Plumb the context instruction through to make hoisting and sinking
// more powerful. Hoisting of loads already works due to the special casing
// above.
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