[llvm-commits] [llvm] r161459 - in /llvm/trunk: lib/Transforms/Scalar/LICM.cpp test/Transforms/LICM/promote-order.ll
Dan Gohman
gohman at apple.com
Tue Aug 7 17:00:26 PDT 2012
Author: djg
Date: Tue Aug 7 19:00:26 2012
New Revision: 161459
URL: http://llvm.org/viewvc/llvm-project?rev=161459&view=rev
Log:
Avoid recomputing the unique exit blocks and their insert points when doing
multiple scalar promotions on a single loop. This also has the effect of
preserving the order of stores sunk out of loops, which is aesthetically
pleasing, and it happens to fix the testcase in PR13542, though it doesn't
fix the underlying problem.
Added:
llvm/trunk/test/Transforms/LICM/promote-order.ll
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=161459&r1=161458&r2=161459&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Tue Aug 7 19:00:26 2012
@@ -175,7 +175,9 @@
bool canSinkOrHoistInst(Instruction &I);
bool isNotUsedInLoop(Instruction &I);
- void PromoteAliasSet(AliasSet &AS);
+ void PromoteAliasSet(AliasSet &AS,
+ SmallVectorImpl<BasicBlock*> &ExitBlocks,
+ SmallVectorImpl<Instruction*> &InsertPts);
};
}
@@ -256,10 +258,13 @@
// Now that all loop invariants have been removed from the loop, promote any
// memory references to scalars that we can.
if (!DisablePromotion && Preheader && L->hasDedicatedExits()) {
+ SmallVector<BasicBlock *, 8> ExitBlocks;
+ SmallVector<Instruction *, 8> InsertPts;
+
// Loop over all of the alias sets in the tracker object.
for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end();
I != E; ++I)
- PromoteAliasSet(*I);
+ PromoteAliasSet(*I, ExitBlocks, InsertPts);
}
// Clear out loops state information for the next iteration
@@ -631,6 +636,7 @@
Value *SomePtr; // Designated pointer to store to.
SmallPtrSet<Value*, 4> &PointerMustAliases;
SmallVectorImpl<BasicBlock*> &LoopExitBlocks;
+ SmallVectorImpl<Instruction*> &LoopInsertPts;
AliasSetTracker &AST;
DebugLoc DL;
int Alignment;
@@ -638,11 +644,12 @@
LoopPromoter(Value *SP,
const SmallVectorImpl<Instruction*> &Insts, SSAUpdater &S,
SmallPtrSet<Value*, 4> &PMA,
- SmallVectorImpl<BasicBlock*> &LEB, AliasSetTracker &ast,
- DebugLoc dl, int alignment)
+ SmallVectorImpl<BasicBlock*> &LEB,
+ SmallVectorImpl<Instruction*> &LIP,
+ AliasSetTracker &ast, DebugLoc dl, int alignment)
: LoadAndStorePromoter(Insts, S), SomePtr(SP),
- PointerMustAliases(PMA), LoopExitBlocks(LEB), AST(ast), DL(dl),
- Alignment(alignment) {}
+ PointerMustAliases(PMA), LoopExitBlocks(LEB), LoopInsertPts(LIP),
+ AST(ast), DL(dl), Alignment(alignment) {}
virtual bool isInstInList(Instruction *I,
const SmallVectorImpl<Instruction*> &) const {
@@ -662,7 +669,7 @@
for (unsigned i = 0, e = LoopExitBlocks.size(); i != e; ++i) {
BasicBlock *ExitBlock = LoopExitBlocks[i];
Value *LiveInValue = SSA.GetValueInMiddleOfBlock(ExitBlock);
- Instruction *InsertPos = ExitBlock->getFirstInsertionPt();
+ Instruction *InsertPos = LoopInsertPts[i];
StoreInst *NewSI = new StoreInst(LiveInValue, SomePtr, InsertPos);
NewSI->setAlignment(Alignment);
NewSI->setDebugLoc(DL);
@@ -684,7 +691,9 @@
/// looping over the stores in the loop, looking for stores to Must pointers
/// which are loop invariant.
///
-void LICM::PromoteAliasSet(AliasSet &AS) {
+void LICM::PromoteAliasSet(AliasSet &AS,
+ SmallVectorImpl<BasicBlock*> &ExitBlocks,
+ SmallVectorImpl<Instruction*> &InsertPts) {
// We can promote this alias set if it has a store, if it is a "Must" alias
// set, if the pointer is loop invariant, and if we are not eliminating any
// volatile loads or stores.
@@ -794,14 +803,20 @@
// location is better than none.
DebugLoc DL = LoopUses[0]->getDebugLoc();
- SmallVector<BasicBlock*, 8> ExitBlocks;
- CurLoop->getUniqueExitBlocks(ExitBlocks);
+ // Figure out the loop exits and their insertion points, if this is the
+ // first promotion.
+ if (ExitBlocks.empty()) {
+ CurLoop->getUniqueExitBlocks(ExitBlocks);
+ InsertPts.resize(ExitBlocks.size());
+ for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
+ InsertPts[i] = ExitBlocks[i]->getFirstInsertionPt();
+ }
// We use the SSAUpdater interface to insert phi nodes as required.
SmallVector<PHINode*, 16> NewPHIs;
SSAUpdater SSA(&NewPHIs);
LoopPromoter Promoter(SomePtr, LoopUses, SSA, PointerMustAliases, ExitBlocks,
- *CurAST, DL, Alignment);
+ InsertPts, *CurAST, DL, Alignment);
// Set up the preheader to have a definition of the value. It is the live-out
// value from the preheader that uses in the loop will use.
Added: llvm/trunk/test/Transforms/LICM/promote-order.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LICM/promote-order.ll?rev=161459&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LICM/promote-order.ll (added)
+++ llvm/trunk/test/Transforms/LICM/promote-order.ll Tue Aug 7 19:00:26 2012
@@ -0,0 +1,41 @@
+; RUN: opt -tbaa -basicaa -licm -S < %s | FileCheck %s
+
+; LICM should keep the stores in their original order when it sinks/promotes them.
+; rdar://12045203
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+ at p = external global i8*
+
+define i32* @_Z4doiti(i32 %n, float* %tmp1, i32* %tmp3) nounwind {
+entry:
+ %cmp1 = icmp slt i32 0, %n
+ br i1 %cmp1, label %for.body.lr.ph, label %for.end
+
+for.body.lr.ph: ; preds = %entry
+ br label %for.body
+
+for.body: ; preds = %for.body, %for.body.lr.ph
+ %i.02 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.body ]
+ store float 1.000000e+00, float* %tmp1, align 4, !tbaa !1
+ store i32 1, i32* %tmp3, align 4, !tbaa !2
+ %inc = add nsw i32 %i.02, 1
+ %cmp = icmp slt i32 %inc, %n
+ br i1 %cmp, label %for.body, label %for.cond.for.end_crit_edge
+
+; CHECK: for.cond.for.end_crit_edge:
+; CHECK: store float 1.000000e+00, float* %tmp1
+; CHECK: store i32 1, i32* %tmp3
+for.cond.for.end_crit_edge: ; preds = %for.body
+ %split = phi i32* [ %tmp3, %for.body ]
+ br label %for.end
+
+for.end: ; preds = %for.cond.for.end_crit_edge, %entry
+ %r.0.lcssa = phi i32* [ %split, %for.cond.for.end_crit_edge ], [ undef, %entry ]
+ ret i32* %r.0.lcssa
+}
+
+!0 = metadata !{metadata !"minimal TBAA"}
+!1 = metadata !{metadata !"float", metadata !0}
+!2 = metadata !{metadata !"int", metadata !0}
More information about the llvm-commits
mailing list