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[Reassociate] Canonicalize constants to RHS operand. 

llvm-svn: 222005
This commit is contained in:
Chad Rosier 2014-11-14 17:05:59 +00:00
parent 477e42a6fb
commit f8b55f1bc5
4 changed files with 24 additions and 19 deletions
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29
llvm/lib/Transforms/Scalar/Reassociate.cpp
View File

@ -176,6 +176,7 @@ namespace {
private:
void BuildRankMap(Function &F);
unsigned getRank(Value *V);
void canonicalizeOperands(Instruction *I);
void ReassociateExpression(BinaryOperator *I);
void RewriteExprTree(BinaryOperator *I, SmallVectorImpl<ValueEntry> &Ops);
Value *OptimizeExpression(BinaryOperator *I,
@ -331,6 +332,20 @@ unsigned Reassociate::getRank(Value *V) {
return ValueRankMap[I] = Rank;
}
void Reassociate::canonicalizeOperands(Instruction *I) {
assert(isa<BinaryOperator>(I) && "Expected binary operator.");
assert(I->isCommutative() && "Expected commutative operator.");
Value *LHS = I->getOperand(0);
Value *RHS = I->getOperand(1);
unsigned LHSRank = getRank(LHS);
unsigned RHSRank = getRank(RHS);
// Canonicalize constants to RHS. Otherwise, sort the operands by rank.
if (isa<Constant>(LHS) || RHSRank < LHSRank)
cast<BinaryOperator>(I)->swapOperands();
}
static BinaryOperator *CreateAdd(Value *S1, Value *S2, const Twine &Name,
Instruction *InsertBefore, Value *FlagsOp) {
if (S1->getType()->isIntegerTy())
@ -2070,18 +2085,8 @@ void Reassociate::OptimizeInst(Instruction *I) {
// FAdd and FMul can be commuted.
unsigned Opcode = I->getOpcode();
if (Opcode == Instruction::FMul || Opcode == Instruction::FAdd) {
Value *LHS = I->getOperand(0);
Value *RHS = I->getOperand(1);
unsigned LHSRank = getRank(LHS);
unsigned RHSRank = getRank(RHS);
// Sort the operands by rank.
if (RHSRank < LHSRank) {
I->setOperand(0, RHS);
I->setOperand(1, LHS);
}
}
if (Opcode == Instruction::FMul || Opcode == Instruction::FAdd)
canonicalizeOperands(I);
// FIXME: We should commute vector instructions as well. However, this
// requires further analysis to determine the effect on later passes.

2
llvm/test/Transforms/Reassociate/2006-04-27-ReassociateVector.ll
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@ -3,7 +3,7 @@
define <4 x float> @test1() {
; CHECK-LABEL: test1
; CHECK-NEXT: %tmp1 = fsub <4 x float> zeroinitializer, zeroinitializer
; CHECK-NEXT: %tmp2 = fmul <4 x float> zeroinitializer, %tmp1
; CHECK-NEXT: %tmp2 = fmul <4 x float> %tmp1, zeroinitializer
; CHECK-NEXT: ret <4 x float> %tmp2
%tmp1 = fsub <4 x float> zeroinitializer, zeroinitializer

8
llvm/test/Transforms/Reassociate/canonicalize-neg-const.ll
View File

@ -3,7 +3,7 @@
; (x + 0.1234 * y) * (x + -0.1234 * y) -> (x + 0.1234 * y) * (x - 0.1234 * y)
define double @test1(double %x, double %y) {
; CHECK-LABEL: @test1
; CHECK-NEXT: fmul double 1.234000e-01, %y
; CHECK-NEXT: fmul double %y, 1.234000e-01
; CHECK-NEXT: fadd double %x, %mul
; CHECK-NEXT: fsub double %x, %mul
; CHECK-NEXT: fmul double %add{{.*}}, %add{{.*}}
@ -64,7 +64,7 @@ define i64 @test4(i64 %x, i64 %y) {
; Canonicalize (x - -0.1234 * y)
define double @test5(double %x, double %y) {
; CHECK-LABEL: @test5
; CHECK-NEXT: fmul double 1.234000e-01, %y
; CHECK-NEXT: fmul double %y, 1.234000e-01
; CHECK-NEXT: fadd double %x, %mul
; CHECK-NEXT: ret double
@ -76,7 +76,7 @@ define double @test5(double %x, double %y) {
; Don't modify (-0.1234 * y - x)
define double @test6(double %x, double %y) {
; CHECK-LABEL: @test6
; CHECK-NEXT: fmul double -1.234000e-01, %y
; CHECK-NEXT: fmul double %y, -1.234000e-01
; CHECK-NEXT: fsub double %mul, %x
; CHECK-NEXT: ret double %sub
@ -88,7 +88,7 @@ define double @test6(double %x, double %y) {
; Canonicalize (-0.1234 * y + x) -> (x - 0.1234 * y)
define double @test7(double %x, double %y) {
; CHECK-LABEL: @test7
; CHECK-NEXT: fmul double 1.234000e-01, %y
; CHECK-NEXT: fmul double %y, 1.234000e-01
; CHECK-NEXT: fsub double %x, %mul
; CHECK-NEXT: ret double %add

4
llvm/test/Transforms/Reassociate/fast-ReassociateVector.ll
View File

@ -1,10 +1,10 @@
; RUN: opt < %s -reassociate -S | FileCheck %s
; Don't handle floating point vector operations.
; Canonicalize operands, but don't optimize floating point vector operations.
define <4 x float> @test1() {
; CHECK-LABEL: test1
; CHECK-NEXT: %tmp1 = fsub fast <4 x float> zeroinitializer, zeroinitializer
; CHECK-NEXT: %tmp2 = fmul fast <4 x float> zeroinitializer, %tmp1
; CHECK-NEXT: %tmp2 = fmul fast <4 x float> %tmp1, zeroinitializer
%tmp1 = fsub fast <4 x float> zeroinitializer, zeroinitializer
%tmp2 = fmul fast <4 x float> zeroinitializer, %tmp1