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Have SimplifyBinOp dispatch Xor, Add and Sub to the corresponding methods

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(they had just been forgotten before).  Adding Xor causes "main" in the
existing testcase 2010-11-01-lshr-mask.ll to be hugely more simplified.

llvm-svn: 122245
This commit is contained in:
Duncan Sands 2010-12-20 14:47:04 +00:00
parent 4781534e1c
commit f72cfa961d
2 changed files with 31 additions and 7 deletions
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32
lib/Analysis/InstructionSimplify.cpp
View File

@ -11,7 +11,9 @@
// that do not require creating new instructions. This does constant folding
// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
// ("and i32 %x, %x" -> "%x").
// ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
// simplified: This is usually true and assuming it simplifies the logic (if
// they have not been simplified then results are correct but maybe suboptimal).
//
//===----------------------------------------------------------------------===//
@ -229,8 +231,9 @@ static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
/// SimplifyAddInst - Given operands for an Add, see if we can
/// fold the result. If not, this returns null.
Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD, const DominatorTree *) {
static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD, const DominatorTree *DT,
unsigned MaxRecurse) {
if (Constant *CLHS = dyn_cast<Constant>(Op0)) {
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
@ -252,6 +255,7 @@ Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
// X + (Y - X) -> Y
// (Y - X) + X -> Y
// Eg: X + -X -> 0
Value *Y = 0;
if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) ||
match(Op0, m_Sub(m_Value(Y), m_Specific(Op1))))
@ -274,10 +278,16 @@ Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
return 0;
}
Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD, const DominatorTree *DT) {
return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit);
}
/// SimplifySubInst - Given operands for a Sub, see if we can
/// fold the result. If not, this returns null.
Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD, const DominatorTree *) {
static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD, const DominatorTree *,
unsigned MaxRecurse) {
if (Constant *CLHS = dyn_cast<Constant>(Op0))
if (Constant *CRHS = dyn_cast<Constant>(Op1)) {
Constant *Ops[] = { CLHS, CRHS };
@ -317,6 +327,11 @@ Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
return 0;
}
Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD, const DominatorTree *DT) {
return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit);
}
/// SimplifyAndInst - Given operands for an And, see if we can
/// fold the result. If not, this returns null.
static Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
@ -826,6 +841,13 @@ static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
switch (Opcode) {
case Instruction::And: return SimplifyAndInst(LHS, RHS, TD, DT, MaxRecurse);
case Instruction::Or: return SimplifyOrInst(LHS, RHS, TD, DT, MaxRecurse);
case Instruction::Xor: return SimplifyXorInst(LHS, RHS, TD, DT, MaxRecurse);
case Instruction::Add: return SimplifyAddInst(LHS, RHS, /* isNSW */ false,
/* isNUW */ false, TD, DT,
MaxRecurse);
case Instruction::Sub: return SimplifySubInst(LHS, RHS, /* isNSW */ false,
/* isNUW */ false, TD, DT,
MaxRecurse);
default:
if (Constant *CLHS = dyn_cast<Constant>(LHS))
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {

6
test/Transforms/InstCombine/2010-11-01-lshr-mask.ll
View File

@ -5,14 +5,16 @@
define i32 @main(i32 %argc) nounwind ssp {
entry:
%tmp3151 = trunc i32 %argc to i8
; CHECK: %tmp3162 = shl i8 %tmp3151, 5
; CHECK: and i8 %tmp3162, 64
; CHECK-NOT: shl
; CHECK-NOT: shr
%tmp3161 = or i8 %tmp3151, -17
%tmp3162 = and i8 %tmp3151, 122
%tmp3163 = xor i8 %tmp3162, -17
%tmp4114 = shl i8 %tmp3163, 6
%tmp4115 = xor i8 %tmp4114, %tmp3163
%tmp4120 = xor i8 %tmp3161, %tmp4115
; CHECK: lshr i8 %tmp4115, 1
; CHECK-NOT: shl i8 %tmp4126, 6
%tmp4126 = lshr i8 %tmp4120, 7
%tmp4127 = mul i8 %tmp4126, 64
%tmp4086 = zext i8 %tmp4127 to i32