mirror of
https://github.com/RPCS3/llvm.git
synced 2025-02-24 04:32:09 +00:00
Re-re-land: Teach CorrelatedValuePropagation to reduce the width of udiv/urem instructions.
Summary: If the operands of a udiv/urem can be proved to fit within a smaller power-of-two-sized type, reduce the width of the udiv/urem. Backed out for causing performance regressions. Re-landing because we've determined that these regressions were noise. Original Differential Revision: https://reviews.llvm.org/D44102 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328096 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Justin Lebar
parent
2f0ad89dc4
commit
0be6cf599c
@ -58,6 +58,7 @@ STATISTIC(NumCmps, "Number of comparisons propagated");
|
||||
STATISTIC(NumReturns, "Number of return values propagated");
|
||||
STATISTIC(NumDeadCases, "Number of switch cases removed");
|
||||
STATISTIC(NumSDivs, "Number of sdiv converted to udiv");
|
||||
STATISTIC(NumUDivs, "Number of udivs whose width was decreased");
|
||||
STATISTIC(NumAShrs, "Number of ashr converted to lshr");
|
||||
STATISTIC(NumSRems, "Number of srem converted to urem");
|
||||
STATISTIC(NumOverflows, "Number of overflow checks removed");
|
||||
@ -432,6 +433,48 @@ static bool hasPositiveOperands(BinaryOperator *SDI, LazyValueInfo *LVI) {
|
||||
return true;
|
||||
}
|
||||
|
||||
/// Try to shrink a udiv/urem's width down to the smallest power of two that's
|
||||
/// sufficient to contain its operands.
|
||||
static bool processUDivOrURem(BinaryOperator *Instr, LazyValueInfo *LVI) {
|
||||
assert(Instr->getOpcode() == Instruction::UDiv ||
|
||||
Instr->getOpcode() == Instruction::URem);
|
||||
if (Instr->getType()->isVectorTy())
|
||||
return false;
|
||||
|
||||
// Find the smallest power of two bitwidth that's sufficient to hold Instr's
|
||||
// operands.
|
||||
auto OrigWidth = Instr->getType()->getIntegerBitWidth();
|
||||
ConstantRange OperandRange(OrigWidth, /*isFullset=*/false);
|
||||
for (Value *Operand : Instr->operands()) {
|
||||
OperandRange = OperandRange.unionWith(
|
||||
LVI->getConstantRange(Operand, Instr->getParent()));
|
||||
}
|
||||
// Don't shrink below 8 bits wide.
|
||||
unsigned NewWidth = std::max<unsigned>(
|
||||
PowerOf2Ceil(OperandRange.getUnsignedMax().getActiveBits()), 8);
|
||||
// NewWidth might be greater than OrigWidth if OrigWidth is not a power of
|
||||
// two.
|
||||
if (NewWidth >= OrigWidth)
|
||||
return false;
|
||||
|
||||
++NumUDivs;
|
||||
auto *TruncTy = Type::getIntNTy(Instr->getContext(), NewWidth);
|
||||
auto *LHS = CastInst::Create(Instruction::Trunc, Instr->getOperand(0), TruncTy,
|
||||
Instr->getName() + ".lhs.trunc", Instr);
|
||||
auto *RHS = CastInst::Create(Instruction::Trunc, Instr->getOperand(1), TruncTy,
|
||||
Instr->getName() + ".rhs.trunc", Instr);
|
||||
auto *BO =
|
||||
BinaryOperator::Create(Instr->getOpcode(), LHS, RHS, Instr->getName(), Instr);
|
||||
auto *Zext = CastInst::Create(Instruction::ZExt, BO, Instr->getType(),
|
||||
Instr->getName() + ".zext", Instr);
|
||||
if (BO->getOpcode() == Instruction::UDiv)
|
||||
BO->setIsExact(Instr->isExact());
|
||||
|
||||
Instr->replaceAllUsesWith(Zext);
|
||||
Instr->eraseFromParent();
|
||||
return true;
|
||||
}
|
||||
|
||||
static bool processSRem(BinaryOperator *SDI, LazyValueInfo *LVI) {
|
||||
if (SDI->getType()->isVectorTy() || !hasPositiveOperands(SDI, LVI))
|
||||
return false;
|
||||
@ -441,6 +484,10 @@ static bool processSRem(BinaryOperator *SDI, LazyValueInfo *LVI) {
|
||||
SDI->getName(), SDI);
|
||||
SDI->replaceAllUsesWith(BO);
|
||||
SDI->eraseFromParent();
|
||||
|
||||
// Try to process our new urem.
|
||||
processUDivOrURem(BO, LVI);
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
@ -460,6 +507,9 @@ static bool processSDiv(BinaryOperator *SDI, LazyValueInfo *LVI) {
|
||||
SDI->replaceAllUsesWith(BO);
|
||||
SDI->eraseFromParent();
|
||||
|
||||
// Try to simplify our new udiv.
|
||||
processUDivOrURem(BO, LVI);
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
@ -595,6 +645,10 @@ static bool runImpl(Function &F, LazyValueInfo *LVI, const SimplifyQuery &SQ) {
|
||||
case Instruction::SDiv:
|
||||
BBChanged |= processSDiv(cast<BinaryOperator>(II), LVI);
|
||||
break;
|
||||
case Instruction::UDiv:
|
||||
case Instruction::URem:
|
||||
BBChanged |= processUDivOrURem(cast<BinaryOperator>(II), LVI);
|
||||
break;
|
||||
case Instruction::AShr:
|
||||
BBChanged |= processAShr(cast<BinaryOperator>(II), LVI);
|
||||
break;
|
||||
|
||||
95
test/Transforms/CorrelatedValuePropagation/udiv.ll
Normal file
95
test/Transforms/CorrelatedValuePropagation/udiv.ll
Normal file
@ -0,0 +1,95 @@
|
||||
; RUN: opt < %s -correlated-propagation -S | FileCheck %s
|
||||
|
||||
; CHECK-LABEL: @test_nop
|
||||
define void @test_nop(i32 %n) {
|
||||
; CHECK udiv i32 %n, 100
|
||||
%div = udiv i32 %n, 100
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test1(
|
||||
define void @test1(i32 %n) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %n, 65535
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: udiv i16
|
||||
%div = udiv i32 %n, 100
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test2(
|
||||
define void @test2(i32 %n) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %n, 65536
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: udiv i32 %n, 100
|
||||
%div = udiv i32 %n, 100
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test3(
|
||||
define void @test3(i32 %m, i32 %n) {
|
||||
entry:
|
||||
%cmp1 = icmp ult i32 %m, 65535
|
||||
%cmp2 = icmp ult i32 %n, 65535
|
||||
%cmp = and i1 %cmp1, %cmp2
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: udiv i16
|
||||
%div = udiv i32 %m, %n
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test4(
|
||||
define void @test4(i32 %m, i32 %n) {
|
||||
entry:
|
||||
%cmp1 = icmp ult i32 %m, 65535
|
||||
%cmp2 = icmp ule i32 %n, 65536
|
||||
%cmp = and i1 %cmp1, %cmp2
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: udiv i32 %m, %n
|
||||
%div = udiv i32 %m, %n
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test5
|
||||
define void @test5(i32 %n) {
|
||||
%trunc = and i32 %n, 65535
|
||||
; CHECK: udiv i16
|
||||
%div = udiv i32 %trunc, 42
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test6
|
||||
define void @test6(i32 %n) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %n, 255
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: udiv i8
|
||||
%div = sdiv i32 %n, 100
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
101
test/Transforms/CorrelatedValuePropagation/urem.ll
Normal file
101
test/Transforms/CorrelatedValuePropagation/urem.ll
Normal file
@ -0,0 +1,101 @@
|
||||
; RUN: opt < %s -correlated-propagation -S | FileCheck %s
|
||||
|
||||
; CHECK-LABEL: @test_nop
|
||||
define void @test_nop(i32 %n) {
|
||||
; CHECK udiv i32 %n, 100
|
||||
%div = udiv i32 %n, 100
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test1(
|
||||
define void @test1(i32 %n) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %n, 65535
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: urem i16
|
||||
%div = urem i32 %n, 100
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test2(
|
||||
define void @test2(i32 %n) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %n, 65536
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: urem i32 %n, 100
|
||||
%div = urem i32 %n, 100
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test3(
|
||||
define void @test3(i32 %m, i32 %n) {
|
||||
entry:
|
||||
%cmp1 = icmp ult i32 %m, 65535
|
||||
%cmp2 = icmp ult i32 %n, 65535
|
||||
%cmp = and i1 %cmp1, %cmp2
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: urem i16
|
||||
%div = urem i32 %m, %n
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test4(
|
||||
define void @test4(i32 %m, i32 %n) {
|
||||
entry:
|
||||
%cmp1 = icmp ult i32 %m, 65535
|
||||
%cmp2 = icmp ule i32 %n, 65536
|
||||
%cmp = and i1 %cmp1, %cmp2
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: urem i32 %m, %n
|
||||
%div = urem i32 %m, %n
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test5
|
||||
define void @test5(i32 %n) {
|
||||
%trunc = and i32 %n, 63
|
||||
; CHECK: urem i8
|
||||
%div = urem i32 %trunc, 42
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @test6
|
||||
define void @test6(i32 %n) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %n, 255
|
||||
br i1 %cmp, label %bb, label %exit
|
||||
|
||||
bb:
|
||||
; CHECK: urem i8
|
||||
%div = srem i32 %n, 100
|
||||
br label %exit
|
||||
|
||||
exit:
|
||||
ret void
|
||||
}
|
||||
|
||||
; CHECK-LABEL: @non_power_of_2
|
||||
define void @non_power_of_2(i24 %n) {
|
||||
%div = urem i24 %n, 42
|
||||
ret void
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user