[llvm-branch-commits] [llvm-branch] r68467 - in /llvm/branches/Apple/Dib: lib/Transforms/Scalar/GVN.cpp test/Transforms/GVN/condprop.ll
Bill Wendling
isanbard at gmail.com
Mon Apr 6 15:01:14 PDT 2009
Author: void
Date: Mon Apr 6 17:01:14 2009
New Revision: 68467
URL: http://llvm.org/viewvc/llvm-project?rev=68467&view=rev
Log:
--- Merging (from foreign repository) r68172 into '.':
A test/Transforms/GVN/condprop.ll
U lib/Transforms/Scalar/GVN.cpp
Enhance GVN to propagate simple conditionals. This fixes PR3921.
Added:
llvm/branches/Apple/Dib/test/Transforms/GVN/condprop.ll
Modified:
llvm/branches/Apple/Dib/lib/Transforms/Scalar/GVN.cpp
Modified: llvm/branches/Apple/Dib/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Dib/lib/Transforms/Scalar/GVN.cpp?rev=68467&r1=68466&r2=68467&view=diff
==============================================================================
--- llvm/branches/Apple/Dib/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/branches/Apple/Dib/lib/Transforms/Scalar/GVN.cpp Mon Apr 6 17:01:14 2009
@@ -121,6 +121,7 @@
AliasAnalysis* AA;
MemoryDependenceAnalysis* MD;
DominatorTree* DT;
+ uint32_t true_vn, false_vn;
uint32_t nextValueNumber;
@@ -138,7 +139,14 @@
Expression create_expression(CallInst* C);
Expression create_expression(Constant* C);
public:
- ValueTable() : nextValueNumber(1) { }
+ ValueTable() : nextValueNumber(1) {
+ true_vn = lookup_or_add(ConstantInt::getTrue());
+ false_vn = lookup_or_add(ConstantInt::getFalse());
+ }
+
+ uint32_t getTrueVN() { return true_vn; }
+ uint32_t getFalseVN() { return false_vn; }
+
uint32_t lookup_or_add(Value* V);
uint32_t lookup(Value* V) const;
void add(Value* V, uint32_t num);
@@ -1294,9 +1302,27 @@
uint32_t nextNum = VN.getNextUnusedValueNumber();
unsigned num = VN.lookup_or_add(I);
+ if (BranchInst* BI = dyn_cast<BranchInst>(I)) {
+ localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
+
+ if (!BI->isConditional() || isa<Constant>(BI->getCondition()))
+ return false;
+
+ Value* branchCond = BI->getCondition();
+ uint32_t condVN = VN.lookup_or_add(branchCond);
+
+ BasicBlock* trueSucc = BI->getSuccessor(0);
+ BasicBlock* falseSucc = BI->getSuccessor(1);
+
+ localAvail[trueSucc]->table.insert(std::make_pair(condVN,
+ ConstantInt::getTrue()));
+ localAvail[falseSucc]->table.insert(std::make_pair(condVN,
+ ConstantInt::getFalse()));
+ return false;
+
// Allocations are always uniquely numbered, so we can save time and memory
- // by fast failing them.
- if (isa<AllocationInst>(I) || isa<TerminatorInst>(I)) {
+ // by fast failing them.
+ } else if (isa<AllocationInst>(I) || isa<TerminatorInst>(I)) {
localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
return false;
}
@@ -1405,18 +1431,11 @@
bool GVN::processBlock(BasicBlock* BB) {
- DomTreeNode* DTN = DT->getNode(BB);
// FIXME: Kill off toErase by doing erasing eagerly in a helper function (and
// incrementing BI before processing an instruction).
SmallVector<Instruction*, 8> toErase;
bool changed_function = false;
- if (DTN->getIDom())
- localAvail[BB] =
- new ValueNumberScope(localAvail[DTN->getIDom()->getBlock()]);
- else
- localAvail[BB] = new ValueNumberScope(0);
-
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
BI != BE;) {
changed_function |= processInstruction(BI, toErase);
@@ -1607,6 +1626,15 @@
bool GVN::iterateOnFunction(Function &F) {
cleanupGlobalSets();
+ for (df_iterator<DomTreeNode*> DI = df_begin(DT->getRootNode()),
+ DE = df_end(DT->getRootNode()); DI != DE; ++DI) {
+ if (DI->getIDom())
+ localAvail[DI->getBlock()] =
+ new ValueNumberScope(localAvail[DI->getIDom()->getBlock()]);
+ else
+ localAvail[DI->getBlock()] = new ValueNumberScope(0);
+ }
+
// Top-down walk of the dominator tree
bool changed = false;
#if 0
Added: llvm/branches/Apple/Dib/test/Transforms/GVN/condprop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Dib/test/Transforms/GVN/condprop.ll?rev=68467&view=auto
==============================================================================
--- llvm/branches/Apple/Dib/test/Transforms/GVN/condprop.ll (added)
+++ llvm/branches/Apple/Dib/test/Transforms/GVN/condprop.ll Mon Apr 6 17:01:14 2009
@@ -0,0 +1,52 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | grep {br i1 false}
+
+ at a = external global i32 ; <i32*> [#uses=7]
+
+define i32 @foo() nounwind {
+entry:
+ %0 = load i32* @a, align 4 ; <i32> [#uses=1]
+ %1 = icmp eq i32 %0, 4 ; <i1> [#uses=1]
+ br i1 %1, label %bb, label %bb1
+
+bb: ; preds = %entry
+ br label %bb8
+
+bb1: ; preds = %entry
+ %2 = load i32* @a, align 4 ; <i32> [#uses=1]
+ %3 = icmp eq i32 %2, 5 ; <i1> [#uses=1]
+ br i1 %3, label %bb2, label %bb3
+
+bb2: ; preds = %bb1
+ br label %bb8
+
+bb3: ; preds = %bb1
+ %4 = load i32* @a, align 4 ; <i32> [#uses=1]
+ %5 = icmp eq i32 %4, 4 ; <i1> [#uses=1]
+ br i1 %5, label %bb4, label %bb5
+
+bb4: ; preds = %bb3
+ %6 = load i32* @a, align 4 ; <i32> [#uses=1]
+ %7 = add i32 %6, 5 ; <i32> [#uses=1]
+ br label %bb8
+
+bb5: ; preds = %bb3
+ %8 = load i32* @a, align 4 ; <i32> [#uses=1]
+ %9 = icmp eq i32 %8, 5 ; <i1> [#uses=1]
+ br i1 %9, label %bb6, label %bb7
+
+bb6: ; preds = %bb5
+ %10 = load i32* @a, align 4 ; <i32> [#uses=1]
+ %11 = add i32 %10, 4 ; <i32> [#uses=1]
+ br label %bb8
+
+bb7: ; preds = %bb5
+ %12 = load i32* @a, align 4 ; <i32> [#uses=1]
+ br label %bb8
+
+bb8: ; preds = %bb7, %bb6, %bb4, %bb2, %bb
+ %.0 = phi i32 [ %12, %bb7 ], [ %11, %bb6 ], [ %7, %bb4 ], [ 4, %bb2 ], [ 5, %bb ] ; <i32> [#uses=1]
+ br label %return
+
+return: ; preds = %bb8
+ ret i32 %.0
+}
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