[llvm-commits] CVS: llvm/lib/Transforms/IPO/ConstantMerge.cpp
Chris Lattner
lattner at cs.uiuc.edu
Wed Oct 9 18:17:01 PDT 2002
Changes in directory llvm/lib/Transforms/IPO:
ConstantMerge.cpp updated: 1.17 -> 1.18
---
Log message:
- Dramatically simplify the ConstantMerge code now that
Value::replaceAllUsesWith works with constants correctly.
---
Diffs of the changes:
Index: llvm/lib/Transforms/IPO/ConstantMerge.cpp
diff -u llvm/lib/Transforms/IPO/ConstantMerge.cpp:1.17 llvm/lib/Transforms/IPO/ConstantMerge.cpp:1.18
--- llvm/lib/Transforms/IPO/ConstantMerge.cpp:1.17 Tue Oct 1 17:38:35 2002
+++ llvm/lib/Transforms/IPO/ConstantMerge.cpp Wed Oct 9 18:16:04 2002
@@ -12,23 +12,19 @@
#include "llvm/Transforms/IPO.h"
#include "llvm/Module.h"
-#include "llvm/Constants.h"
#include "llvm/Pass.h"
#include "Support/Statistic.h"
namespace {
+ Statistic<> NumMerged("constmerge", "Number of global constants merged");
+
struct ConstantMerge : public Pass {
// run - For this pass, process all of the globals in the module,
// eliminating duplicate constants.
//
bool run(Module &M);
-
- private:
- void replaceUsesOfWith(GlobalVariable *Old, GlobalVariable *New);
- void replaceConstantWith(Constant *Old, Constant *New);
};
- Statistic<> NumMerged("constmerge", "Number of global constants merged");
RegisterOpt<ConstantMerge> X("constmerge","Merge Duplicate Global Constants");
}
@@ -51,7 +47,7 @@
CMap.insert(I, std::make_pair(Init, GV));
} else { // Yup, this is a duplicate!
// Make all uses of the duplicate constant use the cannonical version...
- replaceUsesOfWith(GV, I->second);
+ GV->replaceAllUsesWith(I->second);
// Delete the global value from the module... and back up iterator to
// not skip the next global...
@@ -63,99 +59,4 @@
}
return MadeChanges;
-}
-
-/// replaceUsesOfWith - Replace all uses of Old with New. For instructions,
-/// this is a really simple matter of replacing the reference to Old with a
-/// reference to New. For constants references, however, we must carefully
-/// build replacement constants to substitute in.
-///
-void ConstantMerge::replaceUsesOfWith(GlobalVariable *Old, GlobalVariable *New){
- while (!Old->use_empty()) {
- User *U = Old->use_back();
- if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(U))
- replaceConstantWith(CPR, ConstantPointerRef::get(New));
- else
- U->replaceUsesOfWith(Old, New);
- }
-}
-
-/// replaceWith - Ok, so we have a constant 'Old' and we want to replace it with
-/// 'New'. To do this, we have to recursively go through the uses of Old,
-/// replacing them with new things. The problem is that if a constant uses Old,
-/// then we need to replace the uses of the constant with uses of the equivalent
-/// constant that uses New instead.
-///
-void ConstantMerge::replaceConstantWith(Constant *Old, Constant *New) {
- while (!Old->use_empty()) {
- User *U = Old->use_back();
-
- if (Constant *C = dyn_cast<Constant>(U)) {
- Constant *Replacement = 0;
-
- // Depending on the type of constant, build a suitable replacement...
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
- if (CE->getOpcode() == Instruction::GetElementPtr) {
- std::vector<Constant*> Indices;
- Constant *Pointer = cast<Constant>(CE->getOperand(0));
- Indices.reserve(CE->getNumOperands()-1);
- if (Pointer == Old) Pointer = New;
-
- for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i) {
- Constant *Val = cast<Constant>(CE->getOperand(i));
- if (Val == Old) Val = New;
- Indices.push_back(Val);
- }
- Replacement = ConstantExpr::getGetElementPtr(Pointer, Indices);
- } else if (CE->getOpcode() == Instruction::Cast) {
- assert(CE->getOperand(0) == Old && "Cast only has one use!");
- Replacement = ConstantExpr::getCast(New, CE->getType());
- } else if (CE->getNumOperands() == 2) {
- Constant *C1 = cast<Constant>(CE->getOperand(0));
- Constant *C2 = cast<Constant>(CE->getOperand(1));
- if (C1 == Old) C1 = New;
- if (C2 == Old) C2 = New;
- Replacement = ConstantExpr::get(CE->getOpcode(), C1, C2);
- } else {
- assert(0 && "Unknown ConstantExpr type!");
- }
-
-
- } else if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
- std::vector<Constant*> Values;
- Values.reserve(CA->getValues().size());
- for (unsigned i = 0, e = CA->getValues().size(); i != e; ++i) {
- Constant *Val = cast<Constant>(CA->getValues()[i]);
- if (Val == Old) Val = New;
- Values.push_back(Val);
- }
-
- Replacement = ConstantArray::get(CA->getType(), Values);
- } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
- std::vector<Constant*> Values;
- Values.reserve(CS->getValues().size());
-
- for (unsigned i = 0, e = CS->getValues().size(); i != e; ++i) {
- Constant *Val = cast<Constant>(CS->getValues()[i]);
- if (Val == Old) Val = New;
- Values.push_back(Val);
- }
-
- Replacement = ConstantStruct::get(CS->getType(), Values);
- } else {
- assert(0 && "Unexpected/unknown constant type!");
- }
-
- // Now that we have a suitable replacement, recursively eliminate C.
- replaceConstantWith(C, Replacement);
-
- } else {
- // If it is not a constant, we can simply replace uses of Old with New.
- U->replaceUsesOfWith(Old, New);
- }
-
- }
-
- // No-one refers to this old dead constant now, destroy it!
- Old->destroyConstant();
}
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