diff options
| author | Ficture Seven <FICTURE7@gmail.com> | 2020-08-05 02:52:33 +0400 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-08-05 08:52:33 +1000 |
| commit | ee22517d92c48eab9643b6fc8ce4dac2b7e95f57 (patch) | |
| tree | 5df92a3e83f9daafba44ad11862683af8185ffaf /ARMeilleure/CodeGen/Optimizations/Optimizer.cs | |
| parent | a33dc2f4919f7fdc8ea9db41c4c70c38cedfd3df (diff) | |
Improve branch operations (#1442)
* Add Compare instruction
* Add BranchIf instruction
* Use test when BranchIf & Compare against 0
* Propagate Compare into BranchIfTrue/False use
- Propagate Compare operations into their BranchIfTrue/False use and
turn these into a BranchIf.
- Clean up Comparison enum.
* Replace BranchIfTrue/False with BranchIf
* Use BranchIf in EmitPtPointerLoad
- Using BranchIf early instead of BranchIfTrue/False improves LCQ and
reduces the amount of work needed by the Optimizer.
EmitPtPointerLoader was a/the big producer of BranchIfTrue/False.
- Fix asserts firing when assembling BitwiseAnd because of type
mismatch in EmitStoreExclusive. This is harmless and should not
cause any diffs.
* Increment PPTC interval version
* Improve IRDumper for BranchIf & Compare
* Use BranchIf in EmitNativeCall
* Clean up
* Do not emit test when immediately preceded by and
Diffstat (limited to 'ARMeilleure/CodeGen/Optimizations/Optimizer.cs')
| -rw-r--r-- | ARMeilleure/CodeGen/Optimizations/Optimizer.cs | 114 |
1 files changed, 109 insertions, 5 deletions
diff --git a/ARMeilleure/CodeGen/Optimizations/Optimizer.cs b/ARMeilleure/CodeGen/Optimizations/Optimizer.cs index 06118bfd..438010a2 100644 --- a/ARMeilleure/CodeGen/Optimizations/Optimizer.cs +++ b/ARMeilleure/CodeGen/Optimizations/Optimizer.cs @@ -2,6 +2,8 @@ using ARMeilleure.IntermediateRepresentation; using ARMeilleure.Translation; using System.Diagnostics; +using static ARMeilleure.IntermediateRepresentation.OperandHelper; + namespace ARMeilleure.CodeGen.Optimizations { static class Optimizer @@ -42,13 +44,25 @@ namespace ARMeilleure.CodeGen.Optimizations Simplification.RunPass(operation); - if (DestIsLocalVar(operation) && IsPropagableCopy(operation)) - { - PropagateCopy(operation); + if (DestIsLocalVar(operation)) + { + if (IsPropagableCompare(operation)) + { + modified |= PropagateCompare(operation); - RemoveNode(block, node); + if (modified && IsUnused(operation)) + { + RemoveNode(block, node); + } + } + else if (IsPropagableCopy(operation)) + { + PropagateCopy(operation); - modified = true; + RemoveNode(block, node); + + modified = true; + } } node = nextNode; @@ -88,6 +102,91 @@ namespace ARMeilleure.CodeGen.Optimizations while (modified); } + private static bool PropagateCompare(Operation compOp) + { + // Try to propagate Compare operations into their BranchIf uses, when these BranchIf uses are in the form + // of: + // + // - BranchIf %x, 0x0, Equal ;; i.e BranchIfFalse %x + // - BranchIf %x, 0x0, NotEqual ;; i.e BranchIfTrue %x + // + // The commutative property of Equal and NotEqual is taken into consideration as well. + // + // For example: + // + // %x = Compare %a, %b, comp + // BranchIf %x, 0x0, NotEqual + // + // => + // + // BranchIf %a, %b, comp + + static bool IsZeroBranch(Operation operation, out Comparison compType) + { + compType = Comparison.Equal; + + if (operation.Instruction != Instruction.BranchIf) + { + return false; + } + + Operand src1 = operation.GetSource(0); + Operand src2 = operation.GetSource(1); + Operand comp = operation.GetSource(2); + + compType = (Comparison)comp.AsInt32(); + + return (src1.Kind == OperandKind.Constant && src1.Value == 0) || + (src2.Kind == OperandKind.Constant && src2.Value == 0); + } + + bool modified = false; + + Operand dest = compOp.Destination; + Operand src1 = compOp.GetSource(0); + Operand src2 = compOp.GetSource(1); + Operand comp = compOp.GetSource(2); + + Comparison compType = (Comparison)comp.AsInt32(); + + Node[] uses = dest.Uses.ToArray(); + + foreach (Node use in uses) + { + if (!(use is Operation operation)) + { + continue; + } + + // If operation is a BranchIf and has a constant value 0 in its RHS or LHS source operands. + if (IsZeroBranch(operation, out Comparison otherCompType)) + { + Comparison propCompType; + + if (otherCompType == Comparison.NotEqual) + { + propCompType = compType; + } + else if (otherCompType == Comparison.Equal) + { + propCompType = compType.Invert(); + } + else + { + continue; + } + + operation.SetSource(0, src1); + operation.SetSource(1, src2); + operation.SetSource(2, Const((int)propCompType)); + + modified = true; + } + } + + return modified; + } + private static void PropagateCopy(Operation copyOp) { // Propagate copy source operand to all uses of the destination operand. @@ -143,6 +242,11 @@ namespace ARMeilleure.CodeGen.Optimizations || operation.Instruction == Instruction.CompareAndSwap8); } + private static bool IsPropagableCompare(Operation operation) + { + return operation.Instruction == Instruction.Compare; + } + private static bool IsPropagableCopy(Operation operation) { if (operation.Instruction != Instruction.Copy) |