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add DEBUG and -stats output to earlycse.

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Teach it to CSE the rest of the non-side-effecting instructions.

llvm-svn: 122716
This commit is contained in:
Chris Lattner 2011-01-02 23:19:45 +00:00
parent dbad0b5e40
commit 39d1fb3320
3 changed files with 52 additions and 8 deletions
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38
lib/Transforms/Scalar/EarlyCSE.cpp
View File

@ -14,15 +14,21 @@
#define DEBUG_TYPE "early-cse"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/ScopedHashTable.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(NumSimplify, "Number of insts simplified or DCE'd");
STATISTIC(NumCSE, "Number of insts CSE'd");
namespace {
/// InstValue - Instances of this struct represent available values in the
/// scoped hash table.
@ -35,7 +41,11 @@ namespace {
}
static bool canHandle(Instruction *Inst) {
return isa<CastInst>(Inst);
return isa<CastInst>(Inst) || isa<BinaryOperator>(Inst) ||
isa<GetElementPtrInst>(Inst) || isa<CmpInst>(Inst) ||
isa<SelectInst>(Inst) || isa<ExtractElementInst>(Inst) ||
isa<InsertElementInst>(Inst) || isa<ShuffleVectorInst>(Inst) ||
isa<ExtractValueInst>(Inst) || isa<InsertValueInst>(Inst);
}
static InstValue get(Instruction *I) {
@ -73,8 +83,24 @@ unsigned DenseMapInfo<InstValue>::getHashValue(InstValue Val) {
unsigned Res = 0;
if (CastInst *CI = dyn_cast<CastInst>(Inst))
Res = getHash(CI->getOperand(0)) ^ getHash(CI->getType());
else
assert(0 && "Unhandled instruction kind");
else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Inst))
Res = getHash(BO->getOperand(0)) ^ (getHash(BO->getOperand(1)) << 1);
else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
Res = getHash(CI->getOperand(0));
for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i)
Res ^= getHash(CI->getOperand(i)) << i;
} else if (CmpInst *CI = dyn_cast<CmpInst>(Inst)) {
Res = getHash(CI->getOperand(0)) ^ (getHash(CI->getOperand(1)) << 1) ^
CI->getPredicate();
} else {
assert((isa<SelectInst>(Inst) || isa<ExtractElementInst>(Inst) ||
isa<InsertElementInst>(Inst) || isa<ShuffleVectorInst>(Inst) ||
isa<ExtractValueInst>(Inst) || isa<InsertValueInst>(Inst)) &&
"Unhandled instruction kind");
Res = getHash(CI->getType()) << 4;
for (unsigned i = 0, e = Inst->getNumOperands(); i != e; ++i)
Res ^= getHash(CI->getOperand(i)) << i;
}
return (Res << 1) ^ Inst->getOpcode();
}
@ -152,17 +178,21 @@ bool EarlyCSE::processNode(DomTreeNode *Node) {
// Dead instructions should just be removed.
if (isInstructionTriviallyDead(Inst)) {
DEBUG(dbgs() << "EarlyCSE DCE: " << *Inst << '\n');
Inst->eraseFromParent();
Changed = true;
++NumSimplify;
continue;
}
// If the instruction can be simplified (e.g. X+0 = X) then replace it with
// its simpler value.
if (Value *V = SimplifyInstruction(Inst, TD, DT)) {
DEBUG(dbgs() << "EarlyCSE Simplify: " << *Inst << " to: " << *V << '\n');
Inst->replaceAllUsesWith(V);
Inst->eraseFromParent();
Changed = true;
++NumSimplify;
continue;
}
@ -172,9 +202,11 @@ bool EarlyCSE::processNode(DomTreeNode *Node) {
// See if the instruction has an available value. If so, use it.
if (Instruction *V = AvailableValues->lookup(InstValue::get(Inst))) {
DEBUG(dbgs() << "EarlyCSE CSE: " << *Inst << " to: " << *V << '\n');
Inst->replaceAllUsesWith(V);
Inst->eraseFromParent();
Changed = true;
++NumCSE;
continue;
}

5
lib/Transforms/Scalar/LoopIdiomRecognize.cpp
View File

@ -32,6 +32,9 @@
// for (i) { __real__(*P) = 0; __imag__(*P) = 0; }
// this is also "Example 2" from http://blog.regehr.org/archives/320
//
// This could regognize common matrix multiplies and dot product idioms and
// replace them with calls to BLAS (if linked in??).
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "loop-idiom"
@ -49,8 +52,6 @@
#include "llvm/ADT/Statistic.h"
using namespace llvm;
// TODO: Recognize "N" size array multiplies: replace with call to blas or
// something.
STATISTIC(NumMemSet, "Number of memset's formed from loop stores");
STATISTIC(NumMemCpy, "Number of memcpy's formed from loop load+stores");

15
test/Transforms/EarlyCSE/basic.ll
View File

@ -6,16 +6,27 @@ define void @test1(i8 %V, i32 *%P) {
%A = bitcast i64 42 to double ;; dead
%B = add i32 4, 19 ;; constant folds
store i32 %B, i32* %P
; CHECK-NEXT: store i32 23, i32* %P
%C = zext i8 %V to i32
%D = zext i8 %V to i32 ;; CSE
volatile store i32 %C, i32* %P
volatile store i32 %D, i32* %P
; CHECK-NEXT: %C = zext i8 %V to i32
; CHECK-NEXT: volatile store i32 %C
; CHECK-NEXT: volatile store i32 %C
%E = add i32 %C, %C
%F = add i32 %C, %C
volatile store i32 %E, i32* %P
volatile store i32 %F, i32* %P
; CHECK-NEXT: %E = add i32 %C, %C
; CHECK-NEXT: volatile store i32 %E
; CHECK-NEXT: volatile store i32 %E
%G = add nuw i32 %C, %C ;; not a CSE with E
volatile store i32 %G, i32* %P
; CHECK-NEXT: %G = add nuw i32 %C, %C
; CHECK-NEXT: volatile store i32 %G
ret void
}