[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
Chris Lattner
lattner at cs.uiuc.edu
Tue Aug 2 12:17:09 PDT 2005
Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.360 -> 1.361
---
Log message:
Update to use the new MathExtras.h support for log2 computation.
Patch contributed by Jim Laskey!
---
Diffs of the changes: (+15 -22)
InstructionCombining.cpp | 37 +++++++++++++++----------------------
1 files changed, 15 insertions(+), 22 deletions(-)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.360 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.361
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.360 Wed Jul 27 01:12:34 2005
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Tue Aug 2 14:16:58 2005
@@ -46,6 +46,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/InstVisitor.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Support/PatternMatch.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
@@ -361,19 +362,6 @@
return false;
}
-// Log2 - Calculate the log base 2 for the specified value if it is exactly a
-// power of 2.
-static unsigned Log2(uint64_t Val) {
- assert(Val > 1 && "Values 0 and 1 should be handled elsewhere!");
- unsigned Count = 0;
- while (Val != 1) {
- if (Val & 1) return 0; // Multiple bits set?
- Val >>= 1;
- ++Count;
- }
- return Count;
-}
-
// AddOne, SubOne - Add or subtract a constant one from an integer constant...
static ConstantInt *AddOne(ConstantInt *C) {
return cast<ConstantInt>(ConstantExpr::getAdd(C,
@@ -934,9 +922,11 @@
return BinaryOperator::createNeg(Op0, I.getName());
int64_t Val = (int64_t)cast<ConstantInt>(CI)->getRawValue();
- if (uint64_t C = Log2(Val)) // Replace X*(2^C) with X << C
+ if (isPowerOf2_64(Val)) { // Replace X*(2^C) with X << C
+ uint64_t C = Log2_64(Val);
return new ShiftInst(Instruction::Shl, Op0,
ConstantUInt::get(Type::UByteTy, C));
+ }
} else if (ConstantFP *Op1F = dyn_cast<ConstantFP>(Op1)) {
if (Op1F->isNullValue())
return ReplaceInstUsesWith(I, Op1);
@@ -1039,9 +1029,11 @@
// if so, convert to a right shift.
if (ConstantUInt *C = dyn_cast<ConstantUInt>(RHS))
if (uint64_t Val = C->getValue()) // Don't break X / 0
- if (uint64_t C = Log2(Val))
+ if (isPowerOf2_64(Val)) {
+ uint64_t C = Log2_64(Val);
return new ShiftInst(Instruction::Shr, Op0,
ConstantUInt::get(Type::UByteTy, C));
+ }
// -X/C -> X/-C
if (RHS->getType()->isSigned())
@@ -1072,9 +1064,8 @@
}
uint64_t TVA = STO->getValue(), FVA = SFO->getValue();
- unsigned TSA = 0, FSA = 0;
- if ((TVA == 1 || (TSA = Log2(TVA))) && // Log2 fails for 0 & 1.
- (FVA == 1 || (FSA = Log2(FVA)))) {
+ if (isPowerOf2_64(TVA) && isPowerOf2_64(FVA)) {
+ unsigned TSA = Log2_64(TVA), FSA = Log2_64(FVA);
Constant *TC = ConstantUInt::get(Type::UByteTy, TSA);
Instruction *TSI = new ShiftInst(Instruction::Shr, Op0,
TC, SI->getName()+".t");
@@ -2777,9 +2768,10 @@
// If we have a signed (X % (2^c)) == 0, turn it into an unsigned one.
if (CI->isNullValue() && isa<ConstantSInt>(BO->getOperand(1)) &&
BO->hasOneUse() &&
- cast<ConstantSInt>(BO->getOperand(1))->getValue() > 1)
- if (unsigned L2 =
- Log2(cast<ConstantSInt>(BO->getOperand(1))->getValue())) {
+ cast<ConstantSInt>(BO->getOperand(1))->getValue() > 1) {
+ int64_t V = cast<ConstantSInt>(BO->getOperand(1))->getValue();
+ if (isPowerOf2_64(V)) {
+ unsigned L2 = Log2_64(V);
const Type *UTy = BO->getType()->getUnsignedVersion();
Value *NewX = InsertNewInstBefore(new CastInst(BO->getOperand(0),
UTy, "tmp"), I);
@@ -2789,6 +2781,7 @@
return BinaryOperator::create(I.getOpcode(), NewRem,
Constant::getNullValue(UTy));
}
+ }
break;
case Instruction::Add:
@@ -3638,7 +3631,7 @@
if (match(Op0, m_And(m_Value(), m_ConstantInt(AndRHS))))
if (AndRHS->getRawValue() &&
(AndRHS->getRawValue() & (AndRHS->getRawValue()-1)) == 0) {
- unsigned ShiftAmt = Log2(AndRHS->getRawValue());
+ unsigned ShiftAmt = Log2_64(AndRHS->getRawValue());
// Perform an unsigned shr by shiftamt. Convert input to
// unsigned if it is signed.
Value *In = Op0;
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