[llvm-commits] [llvm] r112325 - in /llvm/trunk: include/llvm/LinkAllPasses.h include/llvm/Transforms/Scalar.h lib/Transforms/Scalar/ValuePropagation.cpp test/Transforms/ValuePropagation/ test/Transforms/ValuePropagation/dg.exp test/Transforms/ValuePropagation/phi.ll test/Transforms/ValuePropagation/select.ll
Owen Anderson
resistor at mac.com
Fri Aug 27 16:31:36 PDT 2010
Author: resistor
Date: Fri Aug 27 18:31:36 2010
New Revision: 112325
URL: http://llvm.org/viewvc/llvm-project?rev=112325&view=rev
Log:
Add a prototype of a new peephole optimizing pass that uses LazyValue info to simplify PHIs and select's.
This pass addresses the missed optimizations from PR2581 and PR4420.
Added:
llvm/trunk/lib/Transforms/Scalar/ValuePropagation.cpp
llvm/trunk/test/Transforms/ValuePropagation/
llvm/trunk/test/Transforms/ValuePropagation/dg.exp
llvm/trunk/test/Transforms/ValuePropagation/phi.ll
llvm/trunk/test/Transforms/ValuePropagation/select.ll
Modified:
llvm/trunk/include/llvm/LinkAllPasses.h
llvm/trunk/include/llvm/Transforms/Scalar.h
Modified: llvm/trunk/include/llvm/LinkAllPasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/LinkAllPasses.h?rev=112325&r1=112324&r2=112325&view=diff
==============================================================================
--- llvm/trunk/include/llvm/LinkAllPasses.h (original)
+++ llvm/trunk/include/llvm/LinkAllPasses.h Fri Aug 27 18:31:36 2010
@@ -149,6 +149,7 @@
(void) llvm::createLintPass();
(void) llvm::createSinkingPass();
(void) llvm::createLowerAtomicPass();
+ (void) llvm::createValuePropagationPass();
(void)new llvm::IntervalPartition();
(void)new llvm::FindUsedTypes();
Modified: llvm/trunk/include/llvm/Transforms/Scalar.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar.h?rev=112325&r1=112324&r2=112325&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Scalar.h (original)
+++ llvm/trunk/include/llvm/Transforms/Scalar.h Fri Aug 27 18:31:36 2010
@@ -343,6 +343,12 @@
//
Pass *createLowerAtomicPass();
+//===----------------------------------------------------------------------===//
+//
+// ValuePropagation - Propagate CFG-derived value information
+//
+Pass *createValuePropagationPass();
+
} // End llvm namespace
#endif
Added: llvm/trunk/lib/Transforms/Scalar/ValuePropagation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ValuePropagation.cpp?rev=112325&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/ValuePropagation.cpp (added)
+++ llvm/trunk/lib/Transforms/Scalar/ValuePropagation.cpp Fri Aug 27 18:31:36 2010
@@ -0,0 +1,113 @@
+//===- ValuePropagation.cpp - Propagate information derived control flow --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Value Propagation pass.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "value-propagation"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/LazyValueInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
+using namespace llvm;
+
+namespace {
+ class ValuePropagation : public FunctionPass {
+ LazyValueInfo *LVI;
+
+ bool processSelect(SelectInst *SI);
+ bool processPHI(PHINode *P);
+
+ public:
+ static char ID;
+ ValuePropagation(): FunctionPass(ID) { }
+
+ bool runOnFunction(Function &F);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<LazyValueInfo>();
+ }
+ };
+}
+
+char ValuePropagation::ID = 0;
+INITIALIZE_PASS(ValuePropagation, "value-propagation",
+ "Value Propagation", false, false);
+
+// Public interface to the Value Propagation pass
+Pass *llvm::createValuePropagationPass() {
+ return new ValuePropagation();
+}
+
+bool ValuePropagation::processSelect(SelectInst *S) {
+ Constant *C = LVI->getConstant(S->getOperand(0), S->getParent());
+ if (!C) return false;
+
+ ConstantInt *CI = dyn_cast<ConstantInt>(C);
+ if (!CI) return false;
+
+ if (CI->isZero()) {
+ S->replaceAllUsesWith(S->getOperand(2));
+ S->eraseFromParent();
+ } else if (CI->isOne()) {
+ S->replaceAllUsesWith(S->getOperand(1));
+ S->eraseFromParent();
+ } else {
+ assert(0 && "Select on constant is neither 0 nor 1?");
+ }
+
+ return true;
+}
+
+bool ValuePropagation::processPHI(PHINode *P) {
+ bool changed = false;
+
+ BasicBlock *BB = P->getParent();
+ for (unsigned i = 0; i < P->getNumIncomingValues(); ++i) {
+ Constant *C = LVI->getConstantOnEdge(P->getIncomingValue(i),
+ P->getIncomingBlock(i),
+ BB);
+ if (!C || C == P->getIncomingValue(i)) continue;
+
+ P->setIncomingValue(i, C);
+ changed = true;
+ }
+
+ if (Value *ConstVal = P->hasConstantValue()) {
+ P->replaceAllUsesWith(ConstVal);
+ P->eraseFromParent();
+ changed = true;
+ }
+
+ return changed;
+}
+
+bool ValuePropagation::runOnFunction(Function &F) {
+ LVI = &getAnalysis<LazyValueInfo>();
+
+ bool changed = false;
+
+ for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
+ for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); BI != BE; ) {
+ Instruction *II = BI++;
+ if (SelectInst *SI = dyn_cast<SelectInst>(II))
+ changed |= processSelect(SI);
+ else if (PHINode *P = dyn_cast<PHINode>(II))
+ changed |= processPHI(P);
+ }
+
+ if (changed)
+ for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
+ SimplifyInstructionsInBlock(FI);
+
+ return changed;
+}
\ No newline at end of file
Added: llvm/trunk/test/Transforms/ValuePropagation/dg.exp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ValuePropagation/dg.exp?rev=112325&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ValuePropagation/dg.exp (added)
+++ llvm/trunk/test/Transforms/ValuePropagation/dg.exp Fri Aug 27 18:31:36 2010
@@ -0,0 +1,3 @@
+load_lib llvm.exp
+
+RunLLVMTests [lsort [glob -nocomplain $srcdir/$subdir/*.ll]]
Added: llvm/trunk/test/Transforms/ValuePropagation/phi.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ValuePropagation/phi.ll?rev=112325&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ValuePropagation/phi.ll (added)
+++ llvm/trunk/test/Transforms/ValuePropagation/phi.ll Fri Aug 27 18:31:36 2010
@@ -0,0 +1,17 @@
+; RUN: opt < %s -value-propagation -S | FileCheck %s
+; PR2581
+
+; CHECK: @run
+define i32 @run(i1 %C) nounwind {
+ br i1 %C, label %exit, label %body
+
+body: ; preds = %0
+; CHECK-NOT: select
+ %A = select i1 %C, i32 10, i32 11 ; <i32> [#uses=1]
+; CHECK: ret i32 11
+ ret i32 %A
+
+exit: ; preds = %0
+; CHECK: ret i32 10
+ ret i32 10
+}
\ No newline at end of file
Added: llvm/trunk/test/Transforms/ValuePropagation/select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ValuePropagation/select.ll?rev=112325&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ValuePropagation/select.ll (added)
+++ llvm/trunk/test/Transforms/ValuePropagation/select.ll Fri Aug 27 18:31:36 2010
@@ -0,0 +1,25 @@
+; RUN: opt < %s -value-propagation -S | FileCheck %s
+; PR4420
+
+declare i1 @ext()
+; CHECK: @foo
+define i1 @foo() {
+entry:
+ %cond = tail call i1 @ext() ; <i1> [#uses=2]
+ br i1 %cond, label %bb1, label %bb2
+
+bb1: ; preds = %entry
+ %cond2 = tail call i1 @ext() ; <i1> [#uses=1]
+ br i1 %cond2, label %bb3, label %bb2
+
+bb2: ; preds = %bb1, %entry
+; CHECK-NOT: phi i1
+ %cond_merge = phi i1 [ %cond, %entry ], [ false, %bb1 ] ; <i1> [#uses=1]
+; CHECK: ret i1 false
+ ret i1 %cond_merge
+
+bb3: ; preds = %bb1
+ %res = tail call i1 @ext() ; <i1> [#uses=1]
+; CHECK: ret i1 %res
+ ret i1 %res
+}
\ No newline at end of file
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