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[SILOptimizer] Remove Identity instructions - Peephole in SimplifyInstruction #5633

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Merged
merged 1 commit into from
Nov 3, 2016
Merged

[SILOptimizer] Remove Identity instructions - Peephole in SimplifyInstruction #5633

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11 changes: 11 additions & 0 deletions lib/SILOptimizer/Analysis/SimplifyInstruction.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -477,9 +477,20 @@ static SILValue simplifyBuiltin(BuiltinInst *BI) {
switch (Builtin.ID) {
default: break;

case BuiltinValueKind::SExtOrBitCast: {
const SILValue &Op = Args[0];
// extOrBitCast_N_N(x) -> x
if (Op->getType() == BI->getType())
return Op;
}
break;

case BuiltinValueKind::TruncOrBitCast: {
const SILValue &Op = Args[0];
SILValue Result;
// truncOrBitCast_N_N(x) -> x
if (Op->getType() == BI->getType())
return Op;
// trunc(extOrBitCast(x)) -> x
if (match(Op, m_ExtOrBitCast(m_SILValue(Result)))) {
// Truncated back to the same bits we started with.
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22 changes: 22 additions & 0 deletions test/SILOptimizer/sil_simplify_instrs.sil
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Expand Up @@ -96,6 +96,28 @@ bb0(%x : $Builtin.Word):
// CHECK: return %0 : $Builtin.Word
}

// Simplify trunc((x)) -> x with same type
sil @fold_trunc_n_to_n : $@convention(thin) (Builtin.Int64) -> Builtin.Int64 {
bb0(%x : $Builtin.Int64):
%trunc = builtin "truncOrBitCast_Int64_Word"(%x : $Builtin.Int64) : $Builtin.Int64
return %trunc : $Builtin.Int64

// CHECK-LABEL: sil @fold_trunc_n_to_n
// CHECK-NOT: builtin
// CHECK: return %0 : $Builtin.Int64
}

// Simplify sext((x)) -> x with same type
sil @fold_sext_n_to_n : $@convention(thin) (Builtin.Int64) -> Builtin.Int64 {
bb0(%x : $Builtin.Int64):
%trunc = builtin "sextOrBitCast_Int64_Int64"(%x : $Builtin.Int64) : $Builtin.Int64
return %trunc : $Builtin.Int64

// CHECK-LABEL: sil @fold_sext_n_to_n
// CHECK-NOT: builtin
// CHECK: return %0 : $Builtin.Int64
}

class IntClass {
@sil_stored var value: Builtin.Int32 { get set }
init(value: Builtin.Int32)
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